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Brian R
Crazy Horse

USA
1672 Posts

Posted - 17 Feb 2015 :  9:17:12 PM  Show Profile  Reply with Quote
I am looking at different cams because I can not stand another summer listening to the comp XE.

Looking at Lunatti 10510704lK. Has anyone here used it? It is similar to the XE but apparently doesn't slam the crap out of your valves and thus is much quieter.

I would love to hear your experiences.

Thanks

Edited by - Brian R on 17 Feb 2015 11:46:34 PM

RayK
Cochise

USA
925 Posts

Posted - 18 Feb 2015 :  02:55:06 AM  Show Profile  Reply with Quote
What is your intended use?

1969 Firebird 461, #62 iron heads, Comp roller, Performer RPM, Q-Jet Turbo 400 w/ Continental converter. GM 8.5" 10 bolt with 3:73 gears.11.50's@ 119+ MPH
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Bill Boyle
Horse Feathers (Charter Member)

USA
4793 Posts

Posted - 18 Feb 2015 :  08:03:05 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
What XE cam do you have right now that you speak of. You may have referenced it before--just can't remember what it is.

I'm not a fan of the XE grinds and shied away from the XE 274 when my old 270H showed excessive lobe wear. Bob Kaplan sold me his NIB 276H-10 Comp Cam; it's a lot of cam in a street 406. That might be something to consider in your bigger cid engine.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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fbird1969
Sitting Bull

170 Posts

Posted - 18 Feb 2015 :  08:16:08 AM  Show Profile  Reply with Quote
Harold Brookshire stated that the ramps on the voodoo closed only a little over 10% faster than GM stock, compared to 40% faster by the XE.

Dual Energy cams also have an easier ramp than the XE and Voodoo line.

I was considering the VooDoo262 (219/227, 112) for my 400 build but I may shy away and move to the 265DEH for fear of wiping a lobe on my daily driver. Does anyone have experience with these?
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 18 Feb 2015 :  08:36:55 AM  Show Profile  Reply with Quote
Engine: 461, Edelbrock Heads - flow at 310, RARE Oversized RA Maninfolds, 2 1/2 dual exhaust, Cliff Quadrajet,3:55 rear, Turbo 400 tranny, 4200 lb 71 Lemans Sport Convertible. Compression is 9.3:1

COMP Xtreme Energy XE274H 230/236@.050?? 110LSA

Lunati 10510704LK. 233/241 at .050, .504/.527 on the lift, 110 LSA

Use: No real race, just a cruiser with a lot of punch. I am happy with the performance of the XE, just can no longer stand my engine sounding like a worn out piece of junk with 120k miles on it. It has to go. Really not looking for more performance and don't really want less performance. Also, the lope of the XE is just fine. I do not want to have a kidney buster and can not afford a roller setup.

Bill - I can't find the specs on your Cam anywhere - including Comp...?

Thanks

Edited by - Brian R on 18 Feb 2015 08:47:40 AM
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tjs44
Cochise

USA
411 Posts

Posted - 18 Feb 2015 :  10:19:27 AM  Show Profile  Reply with Quote
Why not just contact a pontiac vendor like Dave at SD for his recomend?They deal with these builds almost daily.The cost of a custom cam is virtually the same price as a shelf cam.Most shelf cams are ground on 110s and I have found 112-114 work better in street engines.Tom
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Chicagogoat
Cochise

USA
823 Posts

Posted - 18 Feb 2015 :  10:30:31 AM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
Brian, that voodoo cam is comparable to your current XE274. I'm running the next size bigger cam and biggest in the Voodoo line that has 241/249 dur @.050 and more lift on my 463 with ported KRE D's in conjunction with Rhoads lifters. I can tell you that it has a moderate idle more tame than an XE284 on a 6x 455 combo I had years ago. It has excellent throttle response and eye opening top end despite the Rhoads which can hamper that deal. But it does give a nice compromise for us street guys with power brakes.

Are you sure your CR is 9.3:1? I'm not sure how unless you have dished pistons.

Pure Pontiac: learn it, live it, love it!
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 18 Feb 2015 :  10:38:36 AM  Show Profile  Reply with Quote
Dished piston. I dealt with 2 different 400's running high compression for years. Got sick of constantly tuning and adding gallons of toluene to every tank. I should not have gone this low considering the aluminum heads, but man is it nice never worrying about octane. Lost some power, but it is still a torque mule.
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Bill Boyle
Horse Feathers (Charter Member)

USA
4793 Posts

Posted - 18 Feb 2015 :  1:57:34 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Sorry Brian, I left out a letter. It's the 276AH-10. The part number is: 51-309-4
and is referenced by Comp in their drag race family of cams: drag race hydraulic flat tappet cam

Comp Description: Hydraulic-Bracket race with heavy car. 2500-3000 stall, 9.5 compression, more gear, choppy idle.

RPM Range: 2000-6000

228/236 @ .050" intake/exhaust

.520" on both valves lift with 1.65 ratio rockers

110 LSA set at 106 intake centerline

Exhaust closes at 28 ATDC and Opens at 76 BBDC
Intake closes at 64 ABDC and Open at 32 BTDC



"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 20 Feb 2015 :  08:13:10 AM  Show Profile  Reply with Quote
Thanks All
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Cliff R
Cochise

USA
535 Posts

Posted - 22 Feb 2015 :  07:25:17 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
The cam should be chosen based on the CID, compression ratio, head flow, drivetrain specs, and use of the vehicle.

A 230 @ .050" cam is NOT a big cam in a 455 build. Get away from the 110LSA grinds and push the LSA out to 112 or even 114. Get away from the XE lobes, they are WAY too aggressive and seating velocity too fast. They not only produce a lot of noise, they are tough to tame at high rpm's, and we've seen a lot of high rpm issues with them as the valve train harmonics play a big role with that deal past 5000rpm's or so.

9.3 to 1 CR isn't a deal breaker for the 455, the SD 455's were lower than that, and can manage pretty big cams and make great power without a lot of compression.

From what I've seen on the dyno here, you are NOT fully utilizing 310cfm head flow with 274 degrees seat timing. I've built 455's with unported E-heads and bigger cams with 300 degrees seat timing and they are pretty much done by 5000 rpm's or so.

The low SCR does play a big role with cam choice, as a "big" cam, especially one on a tight LSA is going to idle poorly, sluggish off idle, and not very efficient in the "normal" driving range. That's why we ALWAYS increase the SCR considerably with these engine builds, as it allows us to use a larger cam with less negatives for street use.

Lunati cams don't use the XE style lobes. Following Harold's cam design logic they keep seating velocities no greater than most stock cams, as he did with the Ultradyne lobes. This makes for less noise, and improved valve train stability at high rpm's as well.

The old 231/239 (288/296, 231/239) Ultradyne cam would be a good choice for what you are doing. I'd have it ground on a 112LSA, not 110 to improve idle quality and low speed manners. It still isn't big enough to fully utilize the head flow available, the larger 247/255 grind (304/312, 247/255) would actually be a much better choice, but trumped by the relatively "low" SCR.

Lunati may have those lobe profiles, and Bullet as well, to do a custom grind......Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Feb 2015 :  08:28:51 AM  Show Profile  Reply with Quote
From the old UltraDyne catalog...

Hydraulic Flat Tappet Cam
296/304 239/247 @.050 0.507"/0.530" 110 LS

Hot Street / Bracket cars, 3500 converter or 4-speed

Harold would normally grind it with a 110 lobe separation. Bullet can make it custom with a 112 if desired. However remember the wider LS will reduce overlap and reduce cranking compression, something to consider with a low compression ratio.


http://www.bulletcams.com/
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Cliff R
Cochise

USA
535 Posts

Posted - 22 Feb 2015 :  08:47:32 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
Steve, reducing overlap raises cranking compression, all else being equal. It also improve vacuum at idle speed, spreads out the power curve, pushes peak torque (max VE) a little higher in the rpm range, and improves top end charge some.

Tighter LSA, or moving the lobes closer together increases overlap, and bleeds off more cylinder pressure at cranking and lower rpm's. It also narrows up the power curve slightly, and pulls peak torque down some in the rpm range.

Tighter LSA cams typically idle with more "authority" or "attitude", producing a "thumpy" exhaust note. They also pack more power into a narrower rpm range lower in the rpm range, so often "feel" pretty responsive and powerful. Wider LSA cams produce a broader more "locomotive" like power curve, with no real rush of power anyplace.

I use, and prefer wider LSA grinds for my engines here, at least for the long strokes, 4.21 and greater. I often move the lobes in some (tighter LSA) for the shorter stroke engines......Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Feb 2015 :  09:14:02 AM  Show Profile  Reply with Quote
Not sure where I got that information, I copied my notes on hand. Sorry for any confusion.


Lobe Separation Angle

Here's where we get into some meaty stuff, so stay with us. If you look at the lobe graph, you can see the relationship of the intake and exhaust lobes. One of the variables that make cam designing such a challenge is the relationship of the intake to the exhaust lobe. The number of degrees between the intake and exhaust lobe centerlines establishes what is called the lobe separation angle. As an example, many Crane street camshafts are built using a 112-degree lobe separation angle. This means there are 112 camshaft degrees between the exhaust and intake centerlines. This can be determined from a cam card by adding the exhaust and intake centerline numbers together and then dividing by 2. So if you add a 111-degree exhaust and a 113-degree intake lobe centers and divide by 2, you'd get a 112-degree lobe separation angle. Keep in mind that often the intake centerline and the lobe separation angle will be the same number, but they represent completely different functions.

Valve overlap is a function of both duration and lobe separation angle. If the lobe separation angle remains the same but you increase the duration, the amount of overlap will also increase. Overlap is the time, measured in crankshaft degrees, when the exhaust valve and intake valves are both open. Overlap helps improve engine performance by starting the intake cycle before the exhaust cycle has ended. As overlap increases, this tends to make the idle quality more erratic, or lumpy, while improving midrange and top-end power. This is a very complex subject that we'll just touch on here, but even slight changes in overlap and intake opening and closing points can make a big difference in engine performance.


Comp Cams info on Lobe separation....

Chart here that shows what happens with a change:

http://www.compcams.com/Pages/413/cam-timing-lobe-separation-angle.aspx
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Feb 2015 :  09:22:40 AM  Show Profile  Reply with Quote
Camshaft Lobe Phasing
A Look Inside The Interesting World Of The Overlap Chronicles

http://www.superchevy.com/how-to/95298-camshaft-lobe-phasing/


By narrowing the Lobe Seperation Angle 'LSA' for a given lobe duration, the overlap increases, but the cylinder pressure can be increased as well.

Source:

http://www.wallaceracing.com/cambasics.htm

If you move the lobes closer to each other, the LSA gets smaller/tighter and the overlap is increased. When looking at different cam profiles for an engine, you will always (almost always) see the LSA listed. While this is a very important consideration, the valve overlap is often forgotten. A profile with a tight LSA will also have more overlap and this is what you should be thinking about when picking a cam, but that?s for a different article.

http://www.austincc.edu/wkibbe/camtheory.htm


Edited by - Steve C. on 22 Feb 2015 09:58:29 AM
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Feb 2015 :  10:08:35 AM  Show Profile  Reply with Quote
Additional information here if interested. Again, more often than not my posts are just fodder for conversation around the coffee table, and not necessarly a recommendation by me.

http://www.tildentechnologies.com/Cams/CamPerformance.html

Summary
The most important cam design parameters are the four timing events or equivalently the advance, intake and exhaust duration and lobe separation angle.
Once the four timing parameters are established, the cam should be designed for maximum lift
A quick opening and closing cam will provide better low end performance than one that is slower opening.
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Cliff R
Cochise

USA
535 Posts

Posted - 22 Feb 2015 :  10:09:47 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
Yes, that can happen IF you shorten up the seat timing and advance the intake lobe so it closes sooner.

Tighter LSA does increase dynamic compression, making it happen lower in the rpm range, narrower torque curve, and peak torque occurring earlier. So even if you loose some cranking pressure, dynamic pressure is likely to be higher earlier in the rpm range.

This fact also INCREASES octane requirements, as the improved cylinder filling at lower rpms increases cylinder pressure, once again all else being equal. With that fact in mind, lowering the SCR then installing a cam with tighter LSA and shorter seat timing, with earlier closing intake can actually make the engine MORE octane sensitive, than going to higher compression, larger cam, wider LSA and later closing intake.

So the proverbial "brick wall" at 9.5 to 1 SCR for pump gas becomes complete and utter NONSENSE. I just about want to puke when I follow posts on the subject and read that statement.

I've had quite a few customers come to us with new engine "builds" where they lowered the SCR, smaller cam on tighter LSA, only to have it pound like SLEDGEHAMMERS on pump gas with "normal" timing and fuel curves in it.

The worst ones in the last 6 months have been a 455 with an XE256 cam in it, and two other 455's with the XE262 cam in them, and one poor soul that put a 204/214/112 "generic" Melling cam in one at 9.5 to 1 CR.

You'd think by the year 2015 and all the good info we have out there these days, that no one would fall into that deal.....FWIW.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.

Edited by - Cliff R on 22 Feb 2015 10:11:16 AM
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Feb 2015 :  11:50:40 AM  Show Profile  Reply with Quote
Just for conversation only, not a recommendation here in response to the original poster, or his requirements.

Note Lee Atkinson's cam used in his 455 here:

Ultradyne, 231/239 intake / exhaust @ .050"; advertized duration 288/296 intake/ exhaust; .526" lift intake / .550" lift exhaust; 108 LSA
http://www.pontiacstreetperformance.com/psp/rebuild45500.html

Lee later changed to another UltraDyne cam but a solid flat tappet and worked with Bullet Racing cams to develop it. He went to 247/247 at .050", note a single pattern cam. And again a tight 108 lobe separation. He picked up about 4 mph and about 2-tenths ET. And he reported the drivability was about the same as with the 'smaller' hydraulic flat tappet cam with less duration. It has been noted many times that you can, and normally should, run more duration with a solid flat tappet cam vs a hydraulic flat tappet cam. Example, Comp hyd flat tappet lobe 5203 with 230 degrees at .050 and Comp solid flat tappet lobe 6055 with 236 degrees at .050 both have the same 241 degrees duration delivered 'at the valve' on a spintron machine at .050 lift with a 1.5 rocker ratio. Here the solid flat tappet cam has an additional 6 degrees intake duration.

When I built my last 462 pump gas engine with Edelbrock heads it ended up with a lousy 9.7 static compression ratio, by mistake and not by design. At the time I talked with Chris Mays at Comp Cams about my specific combo and drivetrain, my performance desires AND the situation with the low compression. For those not familiar Chris is a top dog and a well known cam designer at Comp Cams. I also talked with tech at Bullet Racing about my situation. In conjunction with the low compression both agreed with my intention on a single pattern cam and a tight 108 lobe separation. I went with a 254/254 degree solid roller cam on a tight 108 LS. That might appear like a lot of duration but keep in mind with a solid roller cam you can run a ton more duration over a hydraulic flat tappet cam and have similar driveability. I also had about a 80-85 percent exhaust-to-intake flow ratio on my cylinder heads, that also effected my choice in a single pattern cam.
That and my car at the time years ago was limited street use, with 3.73 gears and a loose converter.... and the rowdy idle was music to my ears :) And my goal was a legitimate 10-second street car.

http://www.pontiacstreetperformance.com/psp/rebuild455sc2003.html

Edited by - Steve C. on 22 Feb 2015 12:27:14 PM
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Feb 2015 :  12:03:53 PM  Show Profile  Reply with Quote
Years ago I asked Harold at Ultradyne when he was posting on PY about the subject of a single pattern vs. a dual pattern cam. Here was his reply:

There are two different items at work here.
1.---On most cylinder heads, whenever I have around a 75% exhaust-to-intake ratio, I use an 8 degree bigger exhaust cam. If the ratio is under 70%, I use 12 degrees, and around 80%, only 4. Whenver the ratio gets around 85%, single pattern cams seem to work as good as anything. Rarely do reverse-pattern(intake bigger than exhaust) cams work.
The two times they do, blown alcohol and turbo-charged, are both for putting heat into the engine or the exhaust.
2.---At the same time, it depends upon what you want the engine to do. Single pattern cams have better bottom-end, dual pattern cams have better top-end. At low RPM, the longer power stroke of a single pattern cam puts more torque into the crank. At high RPM, the most important thing is getting exhaust gas out of the engine. You can't get more charge in if old exhaust gas is still in the chamber. This is why the torque curve makes a sudden down-turn at peak horsepower. The exhaust cam has suddenly become inefficient about getting the old exhaust out, and some gas is retained and trapped, and the intake cannot fill completely because of this extra exhaust gas hanging around.
So, for the best overall power curve, on the average you want a dual-pattern cam, and around 8 to 10 degrees more exhaust. However, if a lot of bottom-end is your goal, or you have heads with a high exhaust/intake ratio, a single-pattern cam will work better.
Was this confusing enough? This is based on 30 years(1972-2002) of cam design and application...
Let me know if you have further questions...

UDHarold
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Cliff R
Cochise

USA
535 Posts

Posted - 23 Feb 2015 :  06:39:26 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
"The exhaust cam has suddenly become inefficient about getting the old exhaust out, and some gas is retained and trapped, and the intake cannot fill completely because of this extra exhaust gas hanging around."

Good point, and why what we install AFTER the cylinders heads also becomes a BIG player in this deal.

I remember quite a few years ago when I was drag racing my Ventura with the old iron headed 455 in it, and switched from 2.5" head pipes to 3", and no other changes. I was rewarded with nearly .2 seconds ET at the track and almost 2 mph! I was already using a dual patter camshaft with 9 degrees more exhaust duration than intake duration.

So it's not always just about the camshaft, as intake and exhaust systems are a player here as well.

FWIW, I've done a LOT of camshaft testing, and we installed a 247/254 @ .050" cam in a 455 once on a 108 LSA. It was "roudy" for sure, and one of the hardest hitting 455 engines I've ever worked with. That engine "felt" much stronger than any other 455 I've test driven to date. EXPLOSIVE power in the mid-range, literally felt like you hit the engine with a 250 shot of nitrous. It also idled like a Pro-Stock engine, sounded really good.

Even so, we replaced than cam with a custom ground HR cam from Dave at SD, on a 112lSA and nearly the same .050" specs. We also had Dave port the cylinder heads to 260cfm at the same time. Before the changes the best ever runs for the 69 FB that engine was installed in were 12.28 @ 112mph.

With the new HR cam on a wider LSA and ported head, and NO OTHER CHANGES the car has went 11.30's at 119mph! Even better than that, it idles pretty smooth, makes a LOT more vacuum at idle, and has a smooth/flat power curve. It actually "feels" a LOT slower if you were driving the car and evaluating the performance by the "seat of your pants". This simply happens because the new power curve is more "locomotive" like than like a shot of nitrous. It just pulls hard everyplace, and no rush of power anyplace.

Important for the reader here is that how an engine behaves at idle, off idle and in the "normal" driving range is pretty important when it comes to enjoying your car on a daily basis. Cams with really "tight" LSA's might sound great at a car cruise or in the staging lanes a the track, but we can run just as quick and even quicker using engines that have much better street manners and more user friendly on a daily basis.....FWIW.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.

Edited by - Cliff R on 23 Feb 2015 06:41:10 AM
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Steve C.
Crazy Horse

1672 Posts

Posted - 23 Feb 2015 :  08:17:45 AM  Show Profile  Reply with Quote
Note my numbers reported regarding Lee's cam change was off a bit. Here is what he said yesterday....

I ran an UltraDyne 288/296 HFT for many years in my 455. It was on a 108, and my best performance came with shifting it around 5300.

I later replaced it with an UltraDyne 280/280 SFT, also on a 108. It ran best shifting at 5900.

The HFT had MUCH better power off the line, my converter flashed to 32-3300rpm, and I could get 1.53 60' times with 3.42 gears.

The SFT was softer off the line 1.59-.61, but ran 3mph and .2 quicker in the 1/4 mile.
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Cliff R
Cochise

USA
535 Posts

Posted - 23 Feb 2015 :  08:31:07 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
A slightly larger cam will do exactly what he saw, soften up the bottom end power and pick up some top end charge. A SFT also does not experience the losses that can occur with a hydraulic cam at high rpm's.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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cortcomp
Coyote

USA
5335 Posts

Posted - 23 Feb 2015 :  12:12:53 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
"So the proverbial "brick wall" at 9.5 to 1 SCR for pump gas becomes complete and utter NONSENSE. I just about want to puke when I follow posts on the subject and read that statement."

Before this turns into another "cam war" thread, i just want to throw three cents in:

1) Jim Hand's book is what started the 9.5 myth. More people follow that book like a bible and that's why it's widespread. Maybe have him print a retraction and people will start to move to higher compression setups? The exact phrase is in there, and that you only give up a little power by lower compression to the 9.5 safe zone (which you do, all else equal. Of course we know that when you up compression, things shouldn't be equal. you change cams and other things to get a lot more from the motor without a lot more risk.)

2) Your car runs strong; if i recall, you have aluminum heads and a roller setup correct? The XE and other "fast ramp" cams you hate are in low comp, iron headed, Hydraulic Flat setups. Like 10% of the cost of your setup. You're not making 10x the power though. Laws of diminishing returns and all that.

3) The basics it always comes back to for you, is "Swap heads to higher compression and get a better cam." You've run the numbers, you have the experience, and that works. Now, for the budget guy (of which there are more of than aluminum heads/roller/thousand dollar head prepping job guys), i have yet to get an answer to this question (and again, the answer may be out there, but no one has answered it) :

If you have a 462 with 6x-4 or 6x-8 heads, what cam would you run that would run faster than the fast ramp tight lsa cams? Not talking about valvetrain noise, no switching heads. For a 9.3-9.5 motor, what cam will put up better numbers? (So what cam in the 462 will make more than 450HP/500 ft lbs, all before 5200rpms)

If you find that cam (and lose the valve noise), then you'll be a rich man getting all those XE converts, because that's why they're buying them. Aluminum heads are still too much, rollers are too much, and smog parts like large chamber heads are WAY more available.

Seriously, you can do a total "right" rebuild under 4-5K or literlally swap cams and intakes and some minor work for 1-2k total over a stock smogged 455 that had udner 250 horeses, and get 450HP. I know a lot of people hate those cams, but no one seems to have a better option FOR THAT MARKET, and that market is large.

Same with e-carbs, make a better carb, out of the box, mass produced, that will run on most motors decently, under $400 and you'll be rich. It's not that the e-carb (or fast ramp cams) are OMG amazing, it's that they just do decently and that's enough for most people who aren't running the track but want more than the factory gave them.

Edited by - cortcomp on 23 Feb 2015 4:22:56 PM
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Jim Hand
Buffalo

65 Posts

Posted - 23 Feb 2015 :  5:46:42 PM  Show Profile  Reply with Quote
Cortcomp,
No, I didn't start the "9.5" myth! I have ran at least 10:1 with iron heads and pump gas for at least 20 years. In fact, I wrote an extensive article on the benefits of optimum C R for the Pontiac boards in 1998 and it is posted here on Bill's board at
http://www.pontiacstreetperformance.com/psp/compression.html
You may want to read it carefully. I have always advocated higher CR for best performance but not so much to encourage detonation.

I have run 10.14 on 6X heads since 1999. My book actually states this: "Compresssion ratio is one of the most important parameters of any engine.
Adding compression adds power at all RPM in every case for engines up to about 11.5. You can make a low compression engine run "good", but never as good as if it had optimum compression ratio."

The book proceeds to discuss many of the factors that determine the "optimum" ratio for various combinations of parts and fuel quality. And remember the book was written in 2002-3, and most of us ran iron heads. And if you are not familiar with how my 4050# wagon ran with 6X heads that flow 265 max, 3./55 gear and factory style water pump and alternator, and a 234/244/112 cam with old fashioned "slow" lobes! I can assure you it ran very close to the "modern" setups that use ported Al heads and roller cams!

Jim Hand



Edited by - Jim Hand on 23 Feb 2015 7:31:53 PM
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Jim Hand
Buffalo

65 Posts

Posted - 23 Feb 2015 :  5:53:44 PM  Show Profile  Reply with Quote
Cort,
Switch over to the PY board at
http://forums.maxperformanceinc.com/forums/showthread.php?t=595840
for more info on my wagon. And we actually ran about a tenth quicker and 1 MPH more then that during the last two years we were able to run.

Jim Hand
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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 23 Feb 2015 :  5:55:19 PM  Show Profile  Reply with Quote
And regarding HR cams (one of my Pontiac engines has one) there is all of the crap with roller lifters failing (and taking out engines in some cases) a while back not to mention distributor gear nonsense (bronze...plastic...). Folks who spent a small fortune on certain HR cams to avoid HFT lifter problems (ZDDP reduction in oil...lifter factory burned down....Pennywise the clown put a hex on them...whatever) were rewarded with roller bearings coming apart, premature distributor gear failure and other maladies.

Then the "trick" became putting SR lifters on HR cams (this one actually appeals to me) but was, as is usually the case in this hobby complicated by confusing and contradictory information regarding oiling via restrictors, pushrods or specially made lifters which themselves restrict oil flow to the top end. OR, NOT to restrict at all.

The average guy (or as Cort says "budget guy") gets lost in all this and fears investing hard earned money when the outcome seems uncertain. That's a big reason why there are so many ho hum engine builds out there.

In the end those who have expertise in other things and can't do this stuff for a living must muddle through and do their due diligence, read, study and ask questions which unfortunately means PMing people on forums sometimes in order to avoid awakening the Ego Giants. Sadly, when the petty bickering starts, Internet forums become the victim and the members suffer as a result.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Jim Hand
Buffalo

65 Posts

Posted - 23 Feb 2015 :  7:09:31 PM  Show Profile  Reply with Quote
Guys,
Here is more info on my old fashioned, old technology car! Jump to PY at:
http://forums.maxperformanceinc.com/forums/showthread.php?t=728886
and scroll down to post 12. I reference PY because most of my photos/attachments are already posted there.

And Cortcomp, will reveal who did start the BS about 9.5 being the max CR with pump gas - Bruce Fulper! He started it back in the mid 90's both in HPP magazine and his web site. I don't know if it is still on his site as I never go there - don't want any resident cooties that might live there!!!!

Jim Hand

Edited by - Jim Hand on 23 Feb 2015 7:11:33 PM
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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 23 Feb 2015 :  7:12:20 PM  Show Profile  Reply with Quote

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5335 Posts

Posted - 23 Feb 2015 :  9:03:40 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I never stated that you never ran over 10:1, or that it doesn't work. Cliff references his hatred for anything under 10:1 compression as "low compression", and attacks it constantly. Sure, it's not as great as you're running with higher compression (Even the 8's compression factory engines weren't terrible, still fun to drive with the torque.), but again i ask, if you have a 9.5:1 455, what cam does anyone recommend to make 450HP? I KNOW Cliff's and your setups work, the numbers don't lie. I'm not contesting that.

However, they made good high compression heads from what, 68-69? And 12 years of low compression heads after that? There is a market for cams to liven up "low" compression motors, the numbers are there and they make money selling them, and for a majority of the engines, they must be working somewhat, i bet comp is making a killing.

As far as referencing your book, page 28, dishing and detonation:

"A dish 3 inches in diameter and .090-inch deep will provide about 9cc gain in combustion chamber volume. This is the amount needed to drop the compression of a 400 from 10.5:1 to about 9.2:1, ideal for a restored stock engine that needs to run on modern pump gas"

Page 73, Heads section (where you also mention you successfully run 10.1:1, a point i mentioned i was aware of above):

"It is possible to run good compression, such as 10.1:1, on pump gas, if you are willing and able to assure all other factors are correct and appropriate. For most, a safer compression ratio would be 9.1 to 9.5:1. Even lower compression is suggested if you plan to drive a lot and buy gas of unknown quality at random locations. But again, the difference between 9:1 and a 10:1 ratio on most engines can mean approximately 6% in total power."


So, in summation:

1) I don't dispute your or Cliff's results with high comp setups, that wasn't even part of what i was saying above.
2) There are way more low comp motors than high comp motors around, 8 years of production difference will do that. Those guys need cams too!
3) Taking a sub 250HP motor and getting it to 450HP with a camshaft swap and a mild head porting job isn't terrible. Sure, it's not what you guys are running, but it's not running like a chevy 305 either.
4) As a newbie, reading your book, it looks like you advise staying under 9.5 (or lower!) for street cars.



A TON of new members come through here every year with low comp setups who can't or don't want to buy high comp heads. They want some more punch and are OK not hitting 500HP. WHAT CAM DO YOU GUYS RECOMMEND TO THEM?! That part never gets answered, and they leave once the arguing starts, and there's the same 10 of us still here.

It's like when people complain about the budget, or the government, or a war, etc. What's the solution? I don't know but i'll complain about how wrong what everyone is doing now!

back to the beginning of the thread, i stated i thought a lunati would be that solution, and i'd love someone to post hard results.

Edit: I want to point out AGAIN that i NEVER said 9.5 was "the max", or that higher compression wouldn't run faster or wasn't safe, or that jim or cliff were liars about their setups or their setups didn't perform.

I just wanted to point out that reading the book as a newbie (which i did and was), that's the impression you get. Also, that not running as fast as possible doesn't make a car a dog or terrible or a waste of money. Some people are just ok with running decent, which i feel these cams achieve, and better than stock looking at the dyno results.


Edited by - cortcomp on 23 Feb 2015 9:11:54 PM
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cortcomp
Coyote

USA
5335 Posts

Posted - 23 Feb 2015 :  9:15:46 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
In response to Phil:

"The average guy (or as Cort says "budget guy") gets lost in all this and fears investing hard earned money when the outcome seems uncertain. That's a big reason why there are so many ho hum engine builds out there."

EXACTLY that! I was that guy, i know those guys, THOSE ARE MOST GUYS. And what I don't think many pros get, MOST guys are happy with good enough! It's only the most determined, maybe, 10% that chase that power further to where cliff and jim are.
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Cliff R
Cochise

USA
535 Posts

Posted - 23 Feb 2015 :  10:29:44 PM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
WAY too much of "who said this" and "I thought they meant that" going on with this thread....IMHO

Anyhow, and what more important to the readers. If you want to make optimum power on pump gas, it's NOT going to be done by LOWERING the static compression ratio then installing a smaller cam with quick ramps on a tight LSA. That's all I'm saying now or have ever said about this subject. Matter of fact, going that route can actually make a lower SCR engine have higher octane requirements than a much higher compression engine with a better cam selection.

The other FACT here is that you are leaving a LOT of power on the table when you do this, as folks don't factor in that higher compression opens up the doors for a larger cam, and when correctly chosen it will idle as well as the lower CR/smaller cammed engine, then make a BUTT LOAD more upper mid-range and top end power.

The big problem with this deal is, that once you have built a "low" compression engine, it's a LOT more difficult to come along and find a "magic" cam for it to make up for all the lost power. So don't expect a long list of recommendations from me, or anyone else when you have went down that path.....FWIW.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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cortcomp
Coyote

USA
5335 Posts

Posted - 23 Feb 2015 :  10:43:11 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Agree with everything you say, except this part:

"Anyhow, and what more important to the readers"

What's important here, is there's a guy who started a thread with 9.3:1 compression and wants a cam change. And here we are saying he can't make any power without upping compression. Sure he could make more than if he stayed with 9.3, but he has 9.3.

The most important question to the readers then, is still, what cam do we give him? I'd honestly like to know too, i considered changing cams but i had other issues with the car and always wanted a 69, so i sold it. If i was gonna keep it that was my only complaint about the car (clacking noise), and it was well presented by XE fans before i made the change. (well, maybe swap the 3.90s out for 3.73s).
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Jim Hand
Buffalo

65 Posts

Posted - 23 Feb 2015 :  11:03:21 PM  Show Profile  Reply with Quote
Cort,
I understand your points. By coincidence, I had to delete some additional material on cams because we were already up to 70,000 words as opposed to the contracted 60,000! The Publisher thought the cam info that was published would be adequate for helping a wide variety of readers select a cam for their specific application. As they were paying the bill, I agreed.

Concerning your specific question about a cam, first I do not think or talk about peak HP numbers -thatt is why I never got involved in Bill's HP/CI deal. The power that matters is the power available in the RPM range you load the engine. Forget numbers such as 450. My recommendation for a modest but great running quiet and affordable 455 is the Summit 2801. It has the intake at 107 as compared to the noisy XE cams at 106 and the lobe separation at 112 rather then the rpm killing 110 of the XE. And it is made by the same folks that make most after market cams so quality would be similar assuming proper break-in. And it would work well from 8 CR up. While not a clone to a Pontiac 068 (due to timimg differences) it will make good power to at least 5000. I have seen this cam run high 12's in a 4000# car.

Same deal with a 400 - use the Summit 2800 - it will have the intake at 107 and also work fine at lower CR. It is very similar in duration to the Pontiac 067. Both cams have lobe design more similar to original, both for durability and minimum noise.

I pushed my car harder then most simply to show the high dollar stuff was not required to run really strong. And I don't care about image or cam sound - just go like heck when the big pedal is pushed!

And you don't need to apologize for anything - it is all good comments and questions (except suggesting I specified 9.5 as max CR on pump gas.) 9.5 probably is max in some cases but that is why I have written so much theory - to try to help folks understand and make better choices. And defining how to dish pistons is not the same as advising it is necessary in all cases.

In summary, my book tried to cover the waterfront and it simply is impossible to cover all situations. Thus, Rocky's newer book on primarily higher RPM, higher cost, and higher performance parts and procedures has been released by Rocky and CarTech.

Jim Hand


Edited by - Jim Hand on 23 Feb 2015 11:05:43 PM
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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 23 Feb 2015 :  11:25:46 PM  Show Profile  Reply with Quote
For reference and discussion purposes Cliff and others have offered suggestions and advice regarding cams for the 8.4:1 SD 455's which IMHO is certainly applicable and useful info. for other similar compression 455 builds (the cam doesn't care about beefier block, 4 bolt mains, dry sump provisions etc.) There IS the roundport difference however I view it as a performance low compression 455 when digesting the cam information.

Something to be gained here and these threads are such a valuable tool when discussions constantly evolve.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5335 Posts

Posted - 23 Feb 2015 :  11:34:21 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Thank you for the reply, and i think that addresses exactly what a lot of people are looking for.

Brian R, what are your thoughts on the summit cams? I have seen the 2801 and 2802 touted a lot, do you think that's what you're looking for?

I'm still interested in the lunati options, because i've read of others having good luck with them but no numbers posted, so i have no idea how they perform vs the summits or XEs.
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Cliff R
Cochise

USA
535 Posts

Posted - 24 Feb 2015 :  06:44:07 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
"For reference and discussion purposes Cliff and others have offered suggestions and advice regarding cams for the 8.4:1 SD 455's which IMHO is certainly applicable and useful info. for other similar compression 455 builds (the cam doesn't care about beefier block, 4 bolt mains, dry sump provisions etc.) There IS the roundport difference however I view it as a performance low compression 455 when digesting the cam information."

Thanks Phil, and you are correct. I'll expand on that a bit so the readers can understand how compression and cam choice effect the overall end result.

A couple of years ago, over on the PY board, a thread comes up there where a guy had just dyno'd his 455 Super Duty engine. It was mostly "stock" with good head work, minor port matching, etc, but nothing really crazy. He did take steps to raise the SCR some, which helps them out considerably when it comes to idle quality and power at lower rpm's, etc. Anyhow, he chose an XE274 cam for it, then puts up the dyno numbers. It was DONE by 4900rpms, yes, DONE. Didn't make much over 400hp from what I can remember, and barely over 500ft lbs torque, with peak torque occurring very early, around 3400rpms nearly as I can remember. The exactly numbers are not important, what happened next is.

I made some comments that he left a LOT of power on the table, and that a bigger cam on a wider LSA would have worked much better, made more power at every rpm, and opened up the doors for the big 455 to shine up past 5000rpm's. Of course over there I immediately got stoned for being the "Comp Cams XE cam basher". Then the OP comes on and said he was more than happy with the results, and only wanted an engine that made good low end power and could care less about power past 5000rpm's, was never going to race the car, blah, blah, blah.

That's all fine and dandy, but my comments were not to put a "big black cloud" over his project. I was pointing out that he built a Super Duty 455 and KILLED it's potential, ending up making no more than, if as much power as putting a 96cc set of "D" ports on a plain old 455 with flat top pistons and better cam choice in it. I've done exactly that, we built a 455 here with plain old 1974 #46 heads without any porting anyplace of any kind, not even a port match. I simply opened them up for 2.11/1.77 valves, good springs/retainers/screw in studs, and bolted them on a zero deck 2 bolt main 455 block. I chose the Crower 60919 cam with and put Rhoad's lifters and high ratio rockers on it. We were nicely rewarded with nearly 1hp/cid and over 500ft lbs torque across most of the loaded rpm range, making peak HP at 5400rpm's.

There are two important parts of my story to remember, or learn from. Installing a relatively "small" cam in a 455 Super Duty engine will NOT allow it to shine anyplace. It's a factory "hot rod" engine, just waiting for someone to deck/square it, tighten up the squish some, and install a better camshaft. Second, we can take a relatively "stock" 455 with untouched late model "D" port heads, and make GREAT power, without spending a lot of money anyplace. Once again, you've got to get the right cam in there to make it happen, then top it with Rhoad's lifters and high ratio rocker arms.

Fast forward a few years. We built the 455 that went into a really nice 73 Formula Super Duty 4 speed car. The owner absolutely MANDATED no porting anyplace on the heads, intake, or exhaust manifolds. We gladly complied, but I MANDATED better rods and pistons, super tight squish, and cutting the heads down for closer to 9 to 1 compression. I also refused to install the flat cam he provided, and chose a custom ground HR cam instead. Not because there is anything wrong with flat cams, but this engine build came up right in the middle of the height of cam/lifter failure issues we were seeing a few years back, and going HR takes that deal out of the equation. Anyhow, we were kindly rewarded once again with nearly 1hp/cid, 540ft lbs peak torque, and over 500ft lbs torque across most of the loaded rpm range with peak HP at 5500rpm's.

We expanded on that same build a few years later with the same HR cam in a 455 HO build, the only difference was CNC ported heads, and were kindly rewarded with 480hp and over 550tq and moved the top end power up a few hundred RPM's. So we have significant experience with lower compression builds, and making great power from them.

Even with everything that we know, and do for the hobby, we continue to see folks dropping compression and going to short seat timing cams on tight LSA's. This can be a DEATH sentence, as we found out yesterday from a phone call to my shop. A dyno operator/engine builder pounded out the rod bearings on a "fresh" 455 he built right on the dyno. He build a 455 in typical fashion with 240cfm #96 heads for 9.5 to 1 compression (safe for pump gas). He then choses and installs a Comp XE cam with 224/230/110 specs. By his own words he "detonated it on the dyno" with "normal" timing/fuel curves in it. Even before he advanced the timing and "pinged" it, he as having trouble making any power and it was DONE at 4800rpm's. He told me in his own words that he has NEVER seen an engine drop power that abruptly, it just "quit pulling", and really wasn't making anywhere near the power they expected anyhow. It made just over 400hp and 500tq.

We had a long conversation about camshafts, CID, and compression ratios. Even though I played no part in that engine at any level, we came up with a larger cam choice on a much wider LSA.

Anyhow, I'll sit down now. I like to explain things by DIRECT example, we have many hundreds to chose from, and have used our testing, dyno, street and track, over many years to get to where we are today. I certainly don't know everything about this deal, but at this point in my learning curve, I certainly know was does NOT work well, so will avoid those parts, and methods of engine building and tuning.....FWIW.....Cliff


If you can read this, thank a teacher. If you can read this in English, thank a Veteran.

Edited by - Cliff R on 24 Feb 2015 06:46:10 AM
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 24 Feb 2015 :  08:51:33 AM  Show Profile  Reply with Quote
Guys,

Always great discussions on Cams and much appreciated.

At this point, I am not sure what is recommended by you guys for MY setup.

My original post:

I am looking at different cams because I can not stand another summer listening to the comp XE.

Looking at Lunatti 10510704lK. Has anyone here used it? It is similar to the XE but apparently doesn't slam the crap out of your valves and thus is much quieter.

I would love to hear your experiences.

___________________________________________________________
My second post:

Engine: 461, Edelbrock Heads - flow at 310, RARE Oversized RA Maninfolds, 2 1/2 dual exhaust, Cliff Quadrajet,3:55 rear, Turbo 400 tranny, 4200 lb 71 Lemans Sport Convertible. Compression is 9.3:1

COMP Xtreme Energy XE274H 230/236@.050?? 110LSA

Lunati 10510704LK. 233/241 at .050, .504/.527 on the lift, 110 LSA

Use: No real race, just a cruiser with a lot of punch. I am happy with the performance of the XE, just can no longer stand my engine sounding like a worn out piece of junk with 120k miles on it. It has to go. Really not looking for more performance and don't really want less performance. Also, the lope of the XE is just fine. I do not want to have a kidney buster and can not afford a roller setup.


Status: I know I should have gone higher compression and that I took a lot of potential out of my build. That said, the performance of the XE is pretty good on this car, I just hate the noise. Maybe the Crower, Maybe the Summit, Maybe the Lunatti - I just don't know. A little more power without vacuum and idle issues would be great, but the main thing is, I HATE DRIVING A SEWING MACHINE....

So: Stuck with a 9.3 compression on an otherwise fairly well built engine. Not about to rebuild the bottom end as the budget doesn't allow. Budget also doesn't allow for rollers. So at 9.3:1 compression, what is best? It seems that this is a gray area for all. It is a better ratio than 8.0:1 and not an optimal 10.5:1 setup. Just a middle of the road setup that I am not looking to beat physics with and also do not want LESS performance than what I have.

Wider LSA = Confused. Example 114. In the past I thought that would bleed off more compression and was great for higher compression engines at the possible risk of lowering vacume too much for power brakes. 110 LSA: Thought this meant less overlap so your compression loss was lessened - good for low compression. As I said, now confused by the above posts.

Cliff: Your wider LSA cam selections: If what I said above is true about LSA's, wouldn't a 114 or even a 112 LSA actually hurt my engine more than help? Not questioning you so much as questioning myself.

Jim: The Summit Cams: Aren't they more of an old school design which I thought had been put up on the shelf in place of more modern designs? If these are what you recommend, being who you are and your extensive experience, I bow to you and would go for it. Again - questioning my own perceptions and not your experience.

Cort: All great, just unsure here. The Lunatti looked like a good Cam until I started reading Cliff's response. It's a 110 LSA which I thought was good for the mid-level compression I am running. Now, perhaps it is too tight?


Thank you very much guys - all of this is great,

Brian

Edited by - Brian R on 24 Feb 2015 09:01:29 AM
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 24 Feb 2015 :  09:09:26 AM  Show Profile  Reply with Quote
quote:
Originally posted by Brian R

Guys,

Always great discussions on Cams and much appreciated.

At this point, I am not sure what is recommended by you guys for MY setup.

My original post:

I am looking at different cams because I can not stand another summer listening to the comp XE.

Looking at Lunatti 10510704lK. Has anyone here used it? It is similar to the XE but apparently doesn't slam the crap out of your valves and thus is much quieter.

I would love to hear your experiences.

___________________________________________________________
My second post:

Engine: 461, Edelbrock Heads - flow at 310, RARE Oversized RA Maninfolds, 2 1/2 dual exhaust, Cliff Quadrajet,3:55 rear, Turbo 400 tranny, 4200 lb 71 Lemans Sport Convertible. Compression is 9.3:1

COMP Xtreme Energy XE274H 230/236@.050?? 110LSA

Lunati 10510704LK. 233/241 at .050, .504/.527 on the lift, 110 LSA

Use: No real race, just a cruiser with a lot of punch. I am happy with the performance of the XE, just can no longer stand my engine sounding like a worn out piece of junk with 120k miles on it. It has to go. Really not looking for more performance and don't really want less performance. Also, the lope of the XE is just fine. I do not want to have a kidney buster and can not afford a roller setup.


Status: I know I should have gone higher compression and that I took a lot of potential out of my build. That said, the performance of the XE is pretty good on this car, I just hate the noise. Maybe the Crower, Maybe the Summit, Maybe the Lunatti - I just don't know. A little more power without vacuum and idle issues would be great, but the main thing is, I HATE DRIVING A SEWING MACHINE....

So: Stuck with a 9.3 compression on an otherwise fairly well built engine. Not about to rebuild the bottom end as the budget doesn't allow. Budget also doesn't allow for rollers. So at 9.3:1 compression, what is best? It seems that this is a gray area for all. It is a better ratio than 8.0:1 and not an optimal 10.5:1 setup. Just a middle of the road setup that I am not looking to beat physics with and also do not want LESS performance than what I have.

Wider LSA = Confused. Example 114. In the past I thought that would bleed off more compression and was great for higher compression engines at the possible risk of lowering vacume too much for power brakes. 110 LSA: Thought this meant less overlap so your compression loss was lessened - good for low compression. As I said, now confused by the above posts.

Cliff: Your wider LSA cam selections: If what I said above is true about LSA's, wouldn't a 114 or even a 112 LSA actually hurt my engine more than help? Not questioning you so much as questioning myself.

Jim: The Summit Cams: Aren't they more of an old school design which I thought had been put up on the shelf in place of more modern designs? If these are what you recommend, being who you are and your extensive experience, I bow to you and would go for it. The 2801 is a LOT less cam than what I am running so I really don'
t get it. Would that mean I am "over-cammed" now? Again - questioning my own perceptions and not your experience.

Cort: All great, just unsure here. The Lunatti looked like a good Cam until I started reading Cliff's response. It's a 110 LSA which I thought was good for the mid-level compression I am running. Now, perhaps it is too tight?


Thank you very much guys - all of this is great,

Brian


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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 24 Feb 2015 :  09:59:42 AM  Show Profile  Reply with Quote
Brian, safe to assume Roundport E-heads? If so, that's why I brought up the SD 455 reference as it could apply here. Plenty of good cam recommendations for that engine and typically the compression is 8.4:1 or a bit higher if the engine was redone.

Fwiw I've run tight and wider LSA cams in L O W compression Pontiac's (as in 7.5:1 to 8:1) with good results. The tighter generally were more punchy off idle and pulled harder in a narrower range but ran out of steam earlier. The wider LSA cams were stronger across the board (I like the locomotive analogy) and pulled right up to the redline. I think an important consideration is that all cams aren't created equal.

Example: I had a Nunzi cam years ago with a tight LSA (110) in a 67 400 with 670 heads and it pulled my head off right up to the redline while the awful Crane cam it replaced had a wide LSA and pinged, had no power and gave me fits with pulling out tons of timing. It was the 80's however and I mistakenly allowed a speed shop "computer program" to recommend the crane cam while Nunzi just spoke to me on the phone and used a computer program in his head called "make it like a this". Those examples are probably not the norm however but do exist.

It would seem the XE cams are in a category of their own as there are other things going on with Comp pushing the envelope of cam lope design. My take on it is they have sacrificed some of the industry parameters that keep camshaft design at a certain reliability and noise level in order to provide more performance on paper. That may be an advantage in certain circles but it doesn't appeal to me or suit my needs.

I noticed that quite a few of the well respected "Ultradyne" cams are ground on a 110 too yet I see none of the complaints typically associated with XE cams. Point is, keep an open mind that many other factors can come in to play with cam design which has proven again and again to be a complicated yet fascinating subject. Since I don't have a masters degree in all things camshaft (I know enough to "get by") I rely on the experts who do this every day and have proven builds out there as shining examples.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 24 Feb 2015 11:18:22 AM
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Steve C.
Crazy Horse

1672 Posts

Posted - 24 Feb 2015 :  10:26:49 AM  Show Profile  Reply with Quote
fbird1969 stated: "Harold Brookshire stated that the ramps on the voodoo closed only a little over 10% faster than GM stock, compared to 40% faster by the XE."

Related, below are comments made by Harold Brookshire years ago regarding UltraDyne lobes (NOT Voodoo lobes). Note his comments on opening and seating velocity and about 'sewing-machine' sound that is directly related to the request by Brian.


"Although I have done only a few Buick cams, I have done an awful lot of Pontiacs and Oldsmobiles. Jim Butler, famed Pontiac engine builder, was my largest buyer of camshafts at UltraDyne, doing over $65,000 a year. He thought they worked very well, until the Recession of 2000 left us with an inability to keep him supplied.
As was said, I do all my cam designs as unsymmetrical cam designs. Although I design my hydraulics just like I do my roller profiles, The information I will give applies just to my hydraulic flat profiles.
Using Harvey Crane's Hydraulic Intensity formula, ALL my .842" tappet designs have an Hydraulic Intensity of 53.88 degrees.
This is the duration at .050" subtracted from the duration at .004", where the SAE has decided that hydraulic durations begin and end.
This Hydraulic Intensity of 53.88 is considered to be very aggressive, yet the cams do not have that 'sewing-machine' sound to them.
The opening side of the cam has a 45.26 degree equivalent Hydraulic Intensity, and the closing side is 62.50 degrees Hydraulic Intensity. The SEATING velocity of the valve is only 37% as fast as the OPENING velocity. This seating velocity is only slightly faster than GM uses on all their engines. At UltraDyne, I have had many hydraulic, as well as solids, go over 100,000 miles on the street. I keep the edge of the tappet about .018" away from the point of contact between the cam and tappet.
That 'sewing-machine' sound is caused by the valves hitting the valve seats too fast. The original High Energy cams, which I designed, produced that sound. I was shutting the valve at .0007"/*, only .0002"/* faster than GM. After hearing about the noise, a little thought made me realize the .0002"/* was only 40% faster than GM.
You do not have to shut the valve faster to keep the charge from getting out.
You have to design the cam so the charge, or inertia ram, is still filling the cylinder when you shut the valve.
Every cam I design, hydraulic, hydraulic roller, solid, solid roller, is designed using the same theory I have used for the past 29 years, and they all make excellent bottom-end torque for their duration."


Now with these comments from Harold in mind. At one time I thought the Voodoo lobes were the same as UltraDyne lobes, since then I have read from conversations on PY that they are not. Apparently Harold while at Lunati revised (some or all ?) lobe designs and developed the Voodoo line.
If you go to the Lunati catalog and look at the Lunati /Voodoo 10510704LK. 233/241 at .050, .504/.527 on the lift, 110 LSA. It is very similar to the XE274H cam being that it is a quick opening and closing cam. You can tell this by the rated or advertised duration in relation to the .050 duration, that and it has more lift. Unfortunately they do not list the 0.200" duration, this would help in comparison to the similar XE lobe.

Now look at the UltraDyne lobes here:
http://www.bulletcams.com/Masters/ultradynemasters.html

Note they appear to be not as 'aggressive' as the XE or Voodoo lobes when you look at the rated duration in relation to the .050 duration and/or valve lift. (plus the 0.200" duration)

My question, and I personally do not have an answer..... Is the Vooddo lobe significantly quieter than a XE lobe ? Apparently the original UltraDyne lobes are quieter but this comparison may not be apples-to-apples to a Voodoo lobe. Unfortunatly we do not have information on the opening and closing rates (velocity) regarding Voodoo lobes.

Edited by - Steve C. on 24 Feb 2015 10:56:02 AM
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cortcomp
Coyote

USA
5335 Posts

Posted - 24 Feb 2015 :  12:56:16 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Cliff:

So in summation (skipping the HR cams because Brian i think was looking to say hydr flat), you're recommend the 60919+rhoads+high ratio rockers for about the same power but more even across the loaded range?

A follow up question, how bad is the noise on the rhoads vs say the XE274? I know it's gone by like 3k rpms, but i spend most of my time around 2200-2500rpms. I thought about moving to a different cam with rhoads but didn't want to be back at the same annoying ticking sounding like a solid cam. I haven't driven a car with rhoads so i don't know how much more or less it sounds like the XE clacking.

Steve C.:

"At one time I thought the Voodoo lobes were the same as UltraDyne lobes, since then I have read from conversations on PY that they are not. Apparently Harold while at Lunati revised (some or all ?) lobe designs and developed the Voodoo line."

I wouldn't think Harold would make those statements then later change how he designed his lobes while at Lunati...that conversation is what made me think that the lunati cam ground near the same would give the same results (good or bad) as the cam he has, minus the clacking. That's why i felt, had i kept my car, maybe i'd throw the $200 at a cam swap with the lunati. I was pretty sure that it probably wouldn't feel different seat of the pants but the noise would be gone.



Brian R:

I can't speak to the LSA of the lunati or even vs the XE you have. Just researching a cam that would behave the same as the XE284 i had (and loved except the clacking), Lunati came up a lot. It would stand to reason that if you wanted to change nothing about your motor but the clacking, that you'd get a cam as close as possible. Of course if you're doing a swap, then maybe a different LSA would ALSO be an option. I kind of viewed the clacking and the LSA as separate issues, you could change one with or without the other, and the clacking was all i was chasing.
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 24 Feb 2015 :  1:21:18 PM  Show Profile  Reply with Quote
Cort - that's why I too have stayed away from the Rhodes option. No more noise...

The LSA question is still out there.

Cliff's options seem like they are for high compression only - maybe I am miss-understanding him.
It seems that there are benefits to the wide LSA but I don't see how they apply to my compression.
That is why I asked the question on the LSA - does it help me, hurt me, or just not matter....?

I am right in the middle...... The Lunatti still seems like it may be a suitable replacement to achieve similar performance on my build but the LSA and different opening/closing pattern still makes it a very different cam even if the numbers are close.

Mr P_Body - are you out there?

One last thing: I doubt this will ever see the track. I love the low RPM power around town that it gives and an occasional stomp on the highway. If it's all out of juice at 4500 to 5000, that's ok with me as I never rev any higher than that anyway.

Thanks again to all.

Edited by - Brian R on 24 Feb 2015 1:31:45 PM
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fbird1969
Sitting Bull

170 Posts

Posted - 24 Feb 2015 :  3:00:26 PM  Show Profile  Reply with Quote
quote:
Originally posted by Steve C.
My question, and I personally do not have an answer..... Is the Vooddo lobe significantly quieter than a XE lobe ? Apparently the original UltraDyne lobes are quieter but this comparison may not be apples-to-apples to a Voodoo lobe. Unfortunatly we do not have information on the opening and closing rates (velocity) regarding Voodoo lobes.



In another forum, IIRC, Harold said that he VooDoo cams were not a variation of the XE cams, but, "XE cams done right." Last night I ordered the 60902 for my engine, and I will be installing it in another month or two.

It is unique in that it has a 112 LSA and closes the intake a few degrees later than the XE262. I trust that Harold designed them to take care of the flaws that plagued the XE series; he seemed confident that he did.

If you're not in a hurry for a new cam, I will be posting how the voodoo performs in my 400 by around mid April. If you are, I would get the Voodoo 276. It's similar in duration to the XE274, but it also does come on a 110 LSA. I would check it out.
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 24 Feb 2015 :  4:19:48 PM  Show Profile  Reply with Quote
No rush at all. There's an 8 foot deep snow bank in front of the garage right now. I can't get within 15 feet of the Lemans......lol

Mid April is when I will be looking to do the work if it's not still snowing.. Please do post your results and thanks.
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Cliff R
Cochise

USA
535 Posts

Posted - 24 Feb 2015 :  7:21:41 PM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
As it relates to this topic and any other that I respond to, I stick to commenting on things that I considerable direct experience with.

I've never built a 455 with 310cfm heads and 9.3 to 1 compression. If I made a cam recommendation, it wouldn't be based on anything we've done here. I will say this much, having 310cfm head flow and using tiny cams with 274 degrees seat timing on 110LSA's with the ICL down at 106 isn't using any of the potential of the heads. Cams that small in a 455 are DONE by 5000rpms, and a stock set of "D" ports will flow a 455 to 5000rpm's before any porting is needed on them. So basically the combo is under cammed for the potential of the heads and CID.

If the objective here is only to replace the noisey cam and make similar power, the Lunati cam mentioned will certainly do that, as it's nearly the same everywhere as the one being replaced. It's also unlikely that it will make more power, as seat timing and lobe placement dictate engine power, and those cams as very close in all areas.

The 455 is still a HUGE engine, and if I inherited that engine I wouldn't hesitate for a second to put more cam in it, up around 290/300 seat timing, but on a wider LSA. I'd also with no hesitation run Rhoad's lifters on it, and high ratio rocker arms, to get the very most out of it. Ticking noise bothers me not in the least, I ran Rhoads lifters on the 60919 cam in my last 455 and never really noticed the noise, or at least it wasn't enough to worry about.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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Steve C.
Crazy Horse

1672 Posts

Posted - 24 Feb 2015 :  7:47:56 PM  Show Profile  Reply with Quote
Out of interest use this calculator:

http://www.wallaceracing.com/overlap-calc.php

Remember to use the advertised duration or rated duration for the input. Not the .050 duration for the differant lobes.

Example, note the differance with a 274/280 cam on a 110 lobe separation vs. a cam with 280/286 with a 112 lobe separation. Both cams have the same 230/236 at .050 duration.

Which one might be a 'better' fit in conjunction with a lower static compression ratio ?

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Chicagogoat
Cochise

USA
823 Posts

Posted - 24 Feb 2015 :  8:22:29 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
This is quoted from Harold the cam engineer himself just as his line of voodoo cams came onto the market about 7 or so years ago:

"The Lunati Voodoo cams are not old Ultradyne cams, although as designer of both there are certain similarities. Both are unsymmetrical, with aggressive opening sides and gentle seating ramps (to control seating noise).
The specs on the Voodoo's are set by Lunati's former sales manager as far as lift and duration. The shape of the curve is the way I design, the names Ultradyne and Voodoo aren't interchangeable."

Pure Pontiac: learn it, live it, love it!
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Chicagogoat
Cochise

USA
823 Posts

Posted - 24 Feb 2015 :  8:50:06 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
What I took from his post is that although he was contracted to design the Voodoo line of cams, all the specs of the cams are set by the marketing wizards at the company but with his famous lobes. I think what he was saying is that the Voodoo's aren't for everybody, so if a different lift, duration, or LSA profile is needed then a customer can refer back to some of his Ultradyne lobes.

I'll repeat what I said earlier the 241/249 @.050 Voodoo in my KRE D 463 with Rhoads has a moderate idle, obviously because if the lifters and its very quick to throttle up and excellent manners and drivablitity on the street. Also note I'm running a Victor and built 1000 cfm 4150 carb up top with 10.5:1 CR. What I've learned is that the gurus are right! Bigger stroke motors with high flowing Alum heads can take more cam not just duration and lift but wider LSA, and still be great down low with Rhoads and give more power all around with 1.65 rockers and .600+ lift since the heads make peak flow well past that. But I'm very happy with this set up and I wanna get my money's worth out of it another couple seasons before I select a bigger custom grind.

Pure Pontiac: learn it, live it, love it!
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Chicagogoat
Cochise

USA
823 Posts

Posted - 24 Feb 2015 :  9:09:16 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
Personally I'd never push CR past 10.75 on a big inch street motor with ported alum heads. It just so happens that most 455-474 bored and stroked Pontiacs with big chamber KRE or E heads with a zero deck and flat top pistons will get you in the 10.4-10.6:1 range, which is an ideal CR for the bigger cams. Any more and you'll need to mill the heads and reduce the chamber size a few ticks which I don't see any guys doing.

Pure Pontiac: learn it, live it, love it!

Edited by - Chicagogoat on 24 Feb 2015 9:10:54 PM
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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 24 Feb 2015 :  9:35:44 PM  Show Profile  Reply with Quote
Yep, that's about where my 455 w/KRE d-ports ended up: 10.3:1

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Steve C.
Crazy Horse

1672 Posts

Posted - 25 Feb 2015 :  09:48:35 AM  Show Profile  Reply with Quote
Paul Carter had good contact with Harold before he died recently. I asked Paul yesterday on the subject. His reply to me...

"Steve, the Voodoo lobes have the same closing velocity as stock GM. They are quiet. Harold split the duration on them as 57.5% on the opening side, and 42.5% on the closing side. Or there about. They open fast, and close slow."

Paul Carter
Carter Cryogenics
www.cartercryo.com
520-409-7236
Koerner Racing Engines
520-294-5758


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