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Miles
Sitting Bull

Canada
138 Posts

Posted - 21 Oct 2017 :  5:33:38 PM  Show Profile  Reply with Quote
Anyone have an idea what duration a mechanical roller camshaft would need, to have the same at the valve duration of a hydraulic roller camshaft? I'm assuming if the rockers are lashed as to specs the valve would start moving later with a solid lifter than if a hydraulic lifter was used due to the rotation needed to take up the valve lash. If a hydraulic roller with a duration of say 238 is compared to a solid roller of 238 duration will the solid have less duration at the valve and by how much?
Hmm I'm having trouble wording this. What duration solid camshaft would one need for the same duration at the valve as a 238/244 hydraulic roller?

Steve C.
Crazy Horse

1672 Posts

Posted - 21 Oct 2017 :  5:55:55 PM  Show Profile  Reply with Quote
There is no pat answer, too many variables involved. Many say 10 extra degree or more. Here with the Comp XE lobe family it is 6 degrees based on Spintron testing...

http://psp.aquacomp.net/topic.asp?TOPIC_ID=4569&SearchTerms=%27at,the,valve%27

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Steve C.
Crazy Horse

1672 Posts

Posted - 21 Oct 2017 :  6:02:53 PM  Show Profile  Reply with Quote
Somewhat related material...

Dyno Shootout: Solid Roller Vs. Hydraulic Roller

http://www.stangtv.com/tech-stories/engine/dyno-shootout-solid-roller-vs-hydraulic-roller/

Solid vs. Hydraulic Roller Camshaft Shootout! Engine Masters Ep. 10

http://www.hotrod.com/articles/solid-vs-hydraulic-roller-camshaft-shootout-engine-masters-ep-10/

Edited by - Steve C. on 21 Oct 2017 6:12:32 PM
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Steve C.
Crazy Horse

1672 Posts

Posted - 21 Oct 2017 :  6:33:13 PM  Show Profile  Reply with Quote
Same amount of duration for a hyd roller as a solid roller ?

Note the comments from Mike Jones about comparing hyd rollers and solid rollers here:

http://speedtalk.com/forum/viewtopic.php?f=1&t=21475&start=0


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Miles
Sitting Bull

Canada
138 Posts

Posted - 22 Oct 2017 :  09:26:06 AM  Show Profile  Reply with Quote
Interesting. I'd like to know how they pressurized the oil when they tested the hydraulic lifters. Something to do with a "spintron machine"? So according to their results it would take a 244 duration solid to have the at the valve duration of a 238 hydraulic, if the solids were lashed at 16 thou.

I found the article "the science of lifters, rolling forward" on the comp site. An article from the magazine " Rolling Thunder", but it was only the first page of the article and I couldn't find the rest. Will you email me the article?
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Steve C.
Crazy Horse

1672 Posts

Posted - 22 Oct 2017 :  11:59:02 AM  Show Profile  Reply with Quote
A commonly held belief is that high valvespring pressure at high engine speeds can push the oil out of the hydraulic lifter creating pump-down. This is possible from internal clearances that directly affect the lifters bleed-down rate. From Spintron research results, the engineers at Comp Cams actually see the running valve duration decrease as RPM increase due to this increased inertial loading. The faster the cam spins, the harder it hits the "shock absorber", and the lifter loses some valuable duration as a result.

From that article it would suggest if you are considering the use of a Comp Xtreme Energy solid roller street lobe you would use 244 degrees intake duration over a XE hydraulic roller lobe with 238 degrees intake duration. Comp solid roller lobe number 4856 is rated with 244 degrees @ .050". That said, I'm not aware of a XE hyd roller lobe with 238 degrees duration at .050" tappet lift. But then these are just numbers and only theory here.

This brings up the question if you would in fact consider a XE solid roller cam at or near that 244 degrees duration. If so then I'll give you my .02 cent opinion, I'd call Lunati and ask if they will custom grind you a solid roller cam using a Pontiac journal diameter with their Voodoo lobes with the specs below. Important, just keep in mind that Comp rates their XE solid roller lobes advertised duration at .015" tappet lift and Lunati will rate theirs at .020" tappet lift. So evaluating the advertised duration between the two will not be apples-to-apples. But if Lunati will provide you with their duration at .015" tappet lift then I will suggest it will have shorter seat timing than the Comp lobe. And the one degree difference in .050" duration between the two is a moot point. The Lunati Voodoo cam has more valuable valve lift to make up for it, 0.578" vs 0.503". Also if interested Lunati can custom grind the cam with any lobe separation desired rather than the 110 listed here.

Voodoo specs.

Advertised Duration (Int/Exh): 273/279
Duration @ .050 (Int/Exh): 243/249
Gross Valve Lift (Int/Exh): .578/.585
LSA/ICL: 110/106

I would also recommend using Crower solid roller lifters with the HIPPO (Hi-Pressure Pin Oiler) option. If interested there is a new set for sale at a good price on the PY board. Also keep in mind the Pontiac valvetrain mass will require more spring pressure to adequately control the valves than what the typical Lunati tech person might suggest with their Voodoo lobes. Do your homework in that specific area of concern.

My e-mail is listed in the Contact Info on this site. Provide me with your e-mail address and I'll forward a scanned copy of that article.


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Edited by - Steve C. on 22 Oct 2017 12:03:30 PM
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tjs44
Cochise

USA
411 Posts

Posted - 22 Oct 2017 :  1:34:31 PM  Show Profile  Reply with Quote
I can tell you from experience after running solid rollers with 200 on the seats set at 6 thou on one of Daves Old Faithful,hyd roller cams and then putting Comp hyd roller lifters on it with 160 on the seats that the came at once acted bigger.The idle was more aggressive.I could not tell much diff on acceleration with the butt dyno.
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Miles
Sitting Bull

Canada
138 Posts

Posted - 22 Oct 2017 :  3:33:40 PM  Show Profile  Reply with Quote
I wonder how the test would have gone if the hydraulic roller had a more comparable lift to the solid roller? The 4873 is 0.376 and the 3315 is only 0.335. Maybe a 3111 which has a lift of 0.3735.

I can tell you from experience, I've gone through two sets of the Comp hydraulic rollers, just wont hold oil. I'll never put another set in again. I know someone's going to say there are hundreds of them out there running great with no problems, but what is an acceptable failure rate? 1%, 5%, 10%. I personally know others who have also given up on them. Two sets of junk are enough for me.
I hope I don't sound too bitter.
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Steve C.
Crazy Horse

1672 Posts

Posted - 23 Oct 2017 :  09:27:35 AM  Show Profile  Reply with Quote
Tom's hydraulic roller cam acted bigger when he changed from using solid roller lifters to hydraulic roller lifters.

This brings up the subject of duration Vs. lash with a solid roller lifter on a hydraulic roller lobe. Below it shows the change in effective duration at the valve from different valve-lash settings on a Comp Cams Xtreme Energy No. 3315 hydraulic roller lobe profile. It assumes 1.5:1 rocker arms.

Duration at the valve indicated under the lash column

0.004" 0.008" 0.012"

0.006" 279.7 273.6 268.6
0.020 262.5 258.9 255.6
0.050" 240.9 238.6 236.5
0.200" 183.2 181.9 180.6


Sorry for the way the numbers came out.
Example, at 0.050" valve lift the duration
at the valve is 240.9 degrees with 0.004" lash.
With 0.008" lash the duration is 238.6 degrees.
With 0.012" lash the duration is 236.5 degrees.

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Edited by - Steve C. on 23 Oct 2017 09:59:25 AM
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tjs44
Cochise

USA
411 Posts

Posted - 23 Oct 2017 :  09:34:08 AM  Show Profile  Reply with Quote
The latest hyd rollers from Comp are made by a diff mfg.They are made in Los Angeles.Comp changed mfg because of poor quality control by their past source.I have one set of the old with no issues and 2 sets of the newest with no issues.And yes there are hundreds out there in pontiacs with no issues.Like most things you only hear from people with problems and not from the ones that dont.Shaver engines is who does their lifters now.Tom
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Steve C.
Crazy Horse

1672 Posts

Posted - 23 Oct 2017 :  11:00:50 AM  Show Profile  Reply with Quote
A local friend replaced the Comp XE 242/248 solid roller cam in his street car with the Old Faithful hydraulic roller cam with 6 degrees less duration, and used his Crower solid roller lifters along the same solid roller valve springs (about 180 lbs seat pressure). At the track it ran about the same, but he did add a bit of weight to the car along with the change so it was not exactly apples-to-apples testing. But he felt it was quieter than the solid roller with the necessary tight .005-.006" lash required. He also reports a little better idle because of the wider 112 lobe separation, that could be expected.


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Miles
Sitting Bull

Canada
138 Posts

Posted - 23 Oct 2017 :  1:13:30 PM  Show Profile  Reply with Quote
You are correct, I haven't said a thing about my push rods, but they work as they are supposed to. Most people don't get too excited when they pay good money for a product and it works, When they pay good money and it doesn't work as advertised, then it is a different story. Yours work, I'm happy about that, maybe I'm just unlucky.

Seems to be a few Pontiac guys running solid rollers on a hydraulic roller camshaft. Any reason why they wouldn't use a solid camshaft? I know one guy who has solids on an OF cam but he did it as the hydraulic lifters failed, he already had the camshaft and didn't want to buy a new one. Is there some kind of an advantage to using solids on a hydraulic roller instead of a solid roller? As you can tell I'm not a camshaft expert.
tjs44, what was the reason you used the solid lifters on the hydraulic cam? If you don't mind my asking, I'm about to get a new camshaft and I'd like to get as much info from as many people as possible before I buy one.
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Steve C.
Crazy Horse

1672 Posts

Posted - 23 Oct 2017 :  1:45:06 PM  Show Profile  Reply with Quote
The subject of using solid roller lifters on a hydraulic roller cam has been beat to death over on the PY board. Do a search if interest. Be aware some hydraulic roller lobe profiles are not compatible with solid roller lifters. The common lobes used within the Pontiac community are the Comp Magnum High Lift hydraulic roller lobes with a tight .005-.006 lash.


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tjs44
Cochise

USA
411 Posts

Posted - 23 Oct 2017 :  8:19:43 PM  Show Profile  Reply with Quote
I first did the solid roller on a hyd roller about 15 or so years ago when Comp came out with their high lift Magnum cams.I bought a cam for my RA V engine and it came as a kit with hyd roller lifters springs and retainers.After getting the kit I asked if the were OK with the setup over 6000 RPMs.After a day or two they called me back and suggested that I send the kit back,keep the cam and they would send me solid roller lifters and springs to match and had me set them at 6 thou.I ran those combos for years with no issue even knowing it was a crutch.Years later when the hyd roller lifters got to whre you can make HP to 7000 and above I started moving back to the hyd rollers and never looked back.My 366 RA V NASCAR engine made HP to right at 6900 when the pull was stopped.Im sure it would have made more yet.I know longer build my own engines,I spec them out and have professional builders like Joe Sherman racing build them.I have never had a hyd roller lifter issue from Comp as long as I have been running them.We always run at least 150lb seat pressure with them,always run 10-30 Mobile 1.I have been building none traditional pontiac engines now for the past 20 plus years like 301 stroker short decks,303 stroker RA V SCCA engines,factory alu pontiac block and head engines.The newest Comp pontiac hyd roller lifter at this time is the only hyd roller lifter with the oil band in the proper location.All others are SBC with pontiac link bars.FWIW,Tom
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Miles
Sitting Bull

Canada
138 Posts

Posted - 24 Oct 2017 :  10:45:25 PM  Show Profile  Reply with Quote
Thank you for that reply, sounds like you used the solid to get more rpm not because any failure with the hydraulic units. What made you change from the solid to the hydraulic on the OF camshaft, because yon were informed of the higher rpm they can now reach or some other reason?
Thanks again.
Al
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Miles
Sitting Bull

Canada
138 Posts

Posted - 25 Oct 2017 :  08:00:17 AM  Show Profile  Reply with Quote
By the way, did you notice any increase or decrease in cylinder cranking pressure when you changed the lifters?
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Steve C.
Crazy Horse

1672 Posts

Posted - 25 Oct 2017 :  08:57:16 AM  Show Profile  Reply with Quote

"I did a back to back, same day dyno test with a 246/252 .400" lobe lift hyd. roller cam in a 468ci engine swapping from hyd. to solid roller lifters and there was no indication of valve float turning the engine up to 6200-6300 rpm, using the 99893 springs set up around 1.800". The solids showed 6-8 more hp over the hyd. above the torque peak."
Dave Bisschop

"I don't go out of my way to recommend people run solid roller lifters on hyd. roller cams, in fact less than 5% of the hyd. roller cams we sell end up with solid roller lifters on them, my personal preference is to run hyd. roller lifters."
Dave Bisschop


A fwiw, regarding using solid roller lifters on a hydraulic roller lobe and valve spring pressure. Based on many enquiries they indicate running additional pressure is not only common but many recommend doing so. That said, based on Dave Bisschop's dyno testing he has found it unnecessary. Below are some of my findings....

This stated from a nationally known engine builder:

"Seat pressure doesn't need to be anywhere near where a solid/solid combo needs to be. It needs to be somewhat higher than in a hydro/hydro combo but not anywhere near as high as a solid/solid combo. In other words, the heads need to be built to do this."

I contacted my Comp Cams Tech Rep regarding running solid roller lifters on Comp Magnum High Lift Hydraulic roller lobes 3122B & 3120B (Old Faithful cam) and his response was a minimum of 150 lbs seat pressure. I feel confident this recommendation was on after run in after the springs loose a bit of pressure, which is common.

I then contacted a well respected independent cam designer who frequently posts on the Speedtalk forum about the topic of running solid roller lifters on hydraulic roller lobes. I mentioned those specific Comp hydraulic roller lobes and informed him as to my Comp Rep's recommendation, his response:

"I don't know enough about the ramps used on those Comp lobes to be able to tell you what seat pressure you need. If they're gentle, 150# would be fine, if they're aggressive, it could take 180# on the seat. Some hydraulic roller cams have an opening ramp that's too aggressive to run with a solid roller lifter.You'll need to check with Comp, so you don't run into any issues."

Valve, retainer and spring weight all have to be taken into consideration when figuring out how much spring pressure is required for an application along with how aggressive the cam lobe is and how much rpm the engine needs to turn to optimize the combo.


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Miles
Sitting Bull

Canada
138 Posts

Posted - 25 Oct 2017 :  11:51:00 AM  Show Profile  Reply with Quote
Interesting, did you get those quotes from the PY site?
Do any of the people who run the solid/hydraulic combo give a reason why they have run that way? Tom said he was sent the solids by Comp, I know a guy who has due to hydraulic roller lifter failure, what is the reason for the others?
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Steve C.
Crazy Horse

1672 Posts

Posted - 25 Oct 2017 :  1:26:40 PM  Show Profile  Reply with Quote
Yes, as I mentioned the topic of running solid roller lifters on a hyd roller cam has been discussed a lot there. For the most part many if not all over there that are doing so are using a cam from Dave Bisschop.

Actual hydraulic roller lifter failures involving needle bearing issues is rare ! The valve lash, and the associated hammering effect, in conjunction with a solid roller lifter is a different ballgame.


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Edited by - Steve C. on 25 Oct 2017 1:30:23 PM
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Miles
Sitting Bull

Canada
138 Posts

Posted - 25 Oct 2017 :  2:06:40 PM  Show Profile  Reply with Quote
I personally don't know of any hydraulic roller needle bearing failures, just failures of the hydraulic portion of the lifter. Maybe the guts of the lifters were just made with poor tolerances or poor materials, or poor workmanship. Whatever the case, they just didn't work, not for long anyway. Reading what I could find on the PY site it seems some are going back to the hydraulics as they feel the problems with the lifters has been addressed. I don't want to take a chance again. Like I said, two bad out of two is my limit, I'll move to solids. I'd like to only buy one, so I'm getting all the info I can absorb.

Still like to know why they went hydraulic/solid in the first place. If there was no problem with the hydraulics why use solids?
And if using a solid roller lifter why not use a solid roller camshaft? Must be some reason or was it just a fad?
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tjs44
Cochise

USA
411 Posts

Posted - 26 Oct 2017 :  09:32:29 AM  Show Profile  Reply with Quote
In todays world if I wanted solids on the street it would be tight lash solid roller cam.I see no reason now to ever run solids on the street.I have 3 engines running at this time with Comp hyd rollers with no issue.In fact I have never had a issue with any of their hyd roller lifters although I do know they had quality control issues with past suppliers.IMO the Shaver hyd roller lifters sold by Comp are the best quality hyd roller lifters for our pontiacs.As said they are the only lifter with the proper oil band for our engines at this time.Tom
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Steve C.
Crazy Horse

1672 Posts

Posted - 26 Oct 2017 :  11:20:08 AM  Show Profile  Reply with Quote
And to somewhat reflect Tom's comment regarding Comp hyd roller lifters....

"Overall the hyd. roller set-ups have been very reliable and 95+% of the ones we've sold (well over a thousand at this point) are using Comp cams hyd. roller lifters and the 99893 springs and out of those we've had some issues with about 2-3% of the lifters. We have customers with tens of thousands of miles on their set-ups with no issues."
Dave Bisschop
2016


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Edited by - Steve C. on 26 Oct 2017 11:21:14 AM
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Miles
Sitting Bull

Canada
138 Posts

Posted - 27 Oct 2017 :  12:03:15 AM  Show Profile  Reply with Quote
Well what is being done for the 3%?
I must be in the 3%. But with me it's 100%, although I've only had two sets. I'd like to be one of the customers with 10,000 miles with no issues.
Just wondering, if someone who now uses the hydraulic rollers with no problems, had a couple of sets fail as mine did, would they be willing to take a chance on a third set going bad just because I said mine were good? 97% of customers are happy, the 3% are tired of the cost of replacement. And I suppose you hear more from the 3% than the 97%, but they may have more to B**ch about.
I think that topic is dead, I just wanted to know about the similarities in duration of solid and hydraulic roller cams.
I guess it's what side of the percentage scale you land on.
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tjs44
Cochise

USA
411 Posts

Posted - 27 Oct 2017 :  09:25:13 AM  Show Profile  Reply with Quote
You can just get a cam MFG lobe list and look at the duration at 50 and 200 and see what they are.This will give you a close idea of how it will act.Myself the duration at 200 is kind of the teller to me.It shows you when you need to look at a lifter bore brace when using a solid roller cam.200 lift at 200 duration is kind of the line in the sand.Good luck with your project.Tom
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