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Rearwheelmaniac
Tribal Scout

USA
19 Posts

Posted - 22 Apr 2020 :  11:23:49 AM  Show Profile  Reply with Quote
Hey guys.

New thread for me, new question from me. So im experimenting with a Lunati 10510704 in my 455. Basically I am looking at making sure I have the components to make this work.

Lunati recommends a spring (73949) Closed 120# @ 1.65", Open 319# @ 1.1". .950" coil bind.
Cam specs are .504/.527 presumably with 1.5 rockers - which i plan to use.
My math is 1.65" - .950"=.7 now what is a good rule of thumb for gap to minimize bind? .050"?
so 1.65"-.950"-.050"=.650 max lift.

If all that is correct. My next question is: I have a new set of Crower 68404's used for one summer. I have seen here and on other threads that the 68404's can be used with this cam but im trying to understand the math proving that.

Specs that I can find are:
open 282# @ 1.1" Closed 113 @ 1.60" Closed 96# @ 1.65"

Per Lunati's recommendations I cannot run the 68404 at 1.65" because the pressures will be lower. these are recommendations to sell their own springs. is there a way to find acceptable ranges for proper opening and closing events? I understand this is a faster ramp cam. I understand who designed them and blah blah. but there are people out there using this combo. If I dont have to use lunatis stronger springs id like to use these as they are barely used.

Steve C.
Chief PONTIAC

2141 Posts

Posted - 22 Apr 2020 :  1:10:24 PM  Show Profile  Reply with Quote
"Keep in mind that most cam manufacturers tend to recommend springs that are on the minimum side of pressure, often too weak. If you add 15-20 lbs for their suggested pressure you'll be pretty close to where you need to be. They tend to base their spring recommendations off of Chevy engines, I think. They don't take into consideration things like valve seat angle, and valve weight, etc."
Paul Carter

Paul has done a lot of dyno testing with Lunati Voodoo cams. Also as I've pointed out before on this site Paul also recommends more seat pressure than Lunati suggests in their catalog, this based on his testing.

Voodoo hyd flat tappet cams. 130-135 lbs seat pressure with valves that have 30 degree seats and 330-340 lbs open. Less with 45 degree seats, still shoot for 110-115 at least and no less than 320 open. That said it might depend on if it was for the 703 or 704 Voodoo cam because on one post he stated minimum 115-120 seat pressure with 45 degree seats. He also recommends to keep coil bind distance at 0.100" or less with the Voodoo hyd flat tappet cams. Also I highly suggest these pressures are minimum after run in. Always keep in mind a spring will more often than not lose a bit of pressure after initial use.

Paul's contact number (520) 409-7236

Of interest: https://www.hotrod.com/articles/how-much-valvespring-coil-bind-clearance-is-safe/

.

Edited by - Steve C. on 22 Apr 2020 1:15:52 PM
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Steve C.
Chief PONTIAC

2141 Posts

Posted - 22 Apr 2020 :  1:55:53 PM  Show Profile  Reply with Quote
The Crower 68404 is also a poor fit... IF in fact you have a verified 1.650" installed height. According to the Crower catalog on line at 1.650" it is rated with only 95 lbs seat pressure !! They list coil bind at 0.950". Do the math, with valve lift at .504"/.527" based on a 1.5 rocker ratio it too will be way too far from coil bind.


http://blog.crower.com/wp-content/uploads/2018/04/CrowerCat_CompleteGuts2018low.pdf
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Steve C.
Chief PONTIAC

2141 Posts

Posted - 22 Apr 2020 :  2:20:44 PM  Show Profile  Reply with Quote
I might add just because you might have a 1.650" installed height does not mean the springs must be installed at that height. I just used that dimension as example for the pressure and/or distance from coil bind. Also if you have springs that are used you should test them at the actual intended installed height with their intended retainers to check if and how much pressure they have lost with use.

Valve springs are probably the most stressed components of an engine.
Yet they are also one of the most oft-overlooked parts in the entire engine.

Edited by - Steve C. on 22 Apr 2020 2:28:11 PM
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Steve C.
Chief PONTIAC

2141 Posts

Posted - 22 Apr 2020 :  2:34:57 PM  Show Profile  Reply with Quote
The 68404 spring is rated at 1.600". However at 1.550" it might have about 128 lbs pressure, and at that installed height with .504" valve lift in theory it would be about .096" away from coil bind. That said, this is for conversation and not intended to cram a bunch of shims under the springs.

This does not represent any endorsement. And unless specified it is not based on personal experience and is offered for general interest only.


.

Edited by - Steve C. on 22 Apr 2020 2:36:50 PM
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Rearwheelmaniac
Tribal Scout

USA
19 Posts

Posted - 22 Apr 2020 :  3:26:54 PM  Show Profile  Reply with Quote
Yeah, I guess my point was, I have these 68404's installed on a set of 6x4s that had about 300 miles on them. They are set at 1.6". If I'm not using rockers to push it at least .050" from coil bind, is it ok to run them at 1.6" as opposed to 1.65" that lunati recommends. Obviously by doing this, spring pressures will be closer to the recommended tolerances.

the second caveat is I have a set of 96's obviously setup with the larger valves 1.77" valves, they have a set of comp springs once used with a solid lift TFX cam. It was only broken in with that cam. They were set at 1.65". I'd have to test the spring pressures but using those heads is a possibility. 2cc's isnt going to make or break my intentions.

quote:
Originally posted by Steve C.

The 68404 spring is rated at 1.600". However at 1.550" it might have about 128 lbs pressure, and at that installed height with .504" valve lift in theory it would be about .096" away from coil bind. That said, this is for conversation and not intended to cram a bunch of shims under the springs.

This does not represent any endorsement. And unless specified it is not based on personal experience and is offered for general interest only.


.


Edited by - Rearwheelmaniac on 22 Apr 2020 3:28:23 PM
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phil400
Crazy Horse

Canada
523 Posts

Posted - 22 Apr 2020 :  8:57:40 PM  Show Profile  Reply with Quote
I think you're confusing IH. Lunati recommends you install their spring at 1.65". If you want to run another spring like say a comp 995 they set up at 1.7 with 115lbs on the seat. You don't have to worry about making a different spring set up at the Lunati springs IH
You just need to get a spring that gives you the open and closed pressure you need at your IH and the safe distance from coil bind.

You can set any spring at any IH but it may not have the right pressure. It all depends on your actual IH

Measure your actual installed height then you cam pick a spring. If your already running the crower 68404 they set upnat 1.6 so that's probably your IH. You need to know your IH so you can then pick a spring that gives you the pressure you need.

Edited by - phil400 on 22 Apr 2020 9:00:00 PM
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Corncob2061
Crazy Horse

USA
669 Posts

Posted - 22 Apr 2020 :  9:57:30 PM  Show Profile  Reply with Quote
There are valve locks that move the install height up or down .050. Looks to me like you need a -.050 keeper and run the Crower 68404 springs at 1.55 if your at 1.6 now. If your at 1.65 your better off with the Lunati springs imho.


These are a 10* keeper. You may have 7* now.
https://www.summitracing.com/parts/cca-630-16

Edited by - Corncob2061 on 22 Apr 2020 10:01:05 PM
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Corncob2061
Crazy Horse

USA
669 Posts

Posted - 23 Apr 2020 :  1:13:26 PM  Show Profile  Reply with Quote
IRC, Max lift on a 68404 is closer to .580-.590 set up a 1.6 IH. Shimming it to 1.55 max lift would be closer .530-.540. Which is still under the 704s lift, the 68404 springs will work fine. There is very little difference between the spring Lunati recommends and the Crowers. IRC, the Lunati have a slightly higher spring rate. The installed height of the Lunati gives a little more room for a bigger rocker arm. The Crower springs do not have quite enough install height to run a bigger rocker arm when set up for more seat pressure, they run into coil bind. The spring rate itself is ok, I would have to look the spring rates up, IRC they are about 20 or 30 lbs per in different. Jay

Edited by - Corncob2061 on 23 Apr 2020 1:14:50 PM
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Rearwheelmaniac
Tribal Scout

USA
19 Posts

Posted - 25 Apr 2020 :  6:23:45 PM  Show Profile  Reply with Quote
Alright, I have a new question regarding this topic. On these 96 heads I have, I cannot seem to recall the exact model of springs I installed 13 years ago. I believe they were comp 995's. My only question that applies here is, when I look at these springs the inner springs are red. Can anyone tell me if the color coding is congruent with comp 995's?

Edited by - Rearwheelmaniac on 26 Apr 2020 9:23:31 PM
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Steve C.
Chief PONTIAC

2141 Posts

Posted - 27 Apr 2020 :  12:01:45 PM  Show Profile  Reply with Quote
The issue with Comp Cams valve springs it could have a color code and it might not. This per a actual conversation with one tech person at Comp Cams. Their source as it goes down the production line sometimes codes them and sometimes not. Also there is a very good chance they might have more than one source for the 995 spring, but this is only my opinion. This said the OPINION of the fellow I talked with suggests it might be yellow for the outer and orange for the inner.

Here is a example: https://www.summitracing.com/parts/cca-995-16?seid=srese1&gclid=Cj0KCQjwhZr1BRCLARIsALjRVQN83y8RZhqxGJRV0cHeJKToKVdM03WB6LmSKSmvvLoCdXdpWpkcIk0aAndTEALw_wcB

But CAUTION, the pictures often shown on various sales web sites may not be the actual picture of the product being sold. So take them with a grain of salt.

Edited by - Steve C. on 27 Apr 2020 12:03:26 PM
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Rearwheelmaniac
Tribal Scout

USA
19 Posts

Posted - 28 Apr 2020 :  07:29:43 AM  Show Profile  Reply with Quote
Understood. They DO appear to be the same as the 995's, red stripe inner, and yellow stripe outer. I'll have the pressures checked before install. I am going to use these for my project as they were only used for break in on a solid lift cam. They are closer to the pressures I need at the recommended height. This also opens the door for longer rockers in the future.
quote:
Originally posted by Steve C.

The issue with Comp Cams valve springs it could have a color code and it might not. This per a actual conversation with one tech person at Comp Cams. Their source as it goes down the production line sometimes codes them and sometimes not. Also there is a very good chance they might have more than one source for the 995 spring, but this is only my opinion. This said the OPINION of the fellow I talked with suggests it might be yellow for the outer and orange for the inner.

Here is a example: https://www.summitracing.com/parts/cca-995-16?seid=srese1&gclid=Cj0KCQjwhZr1BRCLARIsALjRVQN83y8RZhqxGJRV0cHeJKToKVdM03WB6LmSKSmvvLoCdXdpWpkcIk0aAndTEALw_wcB

But CAUTION, the pictures often shown on various sales web sites may not be the actual picture of the product being sold. So take them with a grain of salt.


Edited by - Rearwheelmaniac on 28 Apr 2020 07:30:02 AM
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Rearwheelmaniac
Tribal Scout

USA
19 Posts

Posted - 28 Apr 2020 :  07:34:18 AM  Show Profile  Reply with Quote
Now... I am going to learn to degree this cam, decide on if I need an offset cam key, to around 104*. My only question now is, which heads...Bigger valves or better flow? 96 vs 6X. Thats a debate in and of itself. I'm not starting another cam debate. I'm running this cam and i'll report findings - thats where the knowledge really lies right? Will it detonate on premium. Do I run 9.5:1 or 10:1. will it matter? input is welcome on this specific cam/head setup. Thanks fellas.
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Steve C.
Chief PONTIAC

2141 Posts

Posted - 28 Apr 2020 :  09:54:02 AM  Show Profile  Reply with Quote
When you do check those 995 springs at their intended installed height on the heads do so with the retainer your going to use with them.
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Corncob2061
Crazy Horse

USA
669 Posts

Posted - 28 Apr 2020 :  1:47:45 PM  Show Profile  Reply with Quote
Depends what part of the world your in for matching up pump gas to compression. Just a guess, but the 6x-4 would have a compression very close to optimal. The 96 head have more cc volume. Yes they are suppose to be 96. Not unusual to find one that is closer to 100cc. I have a ported set of 96s milled to 87cc though. It depends on what was done to the heads. Which heads are nicer. 9.5 scr is a pretty good place shoot for in a 455 with the 704 and a stock d port head. May need some milling to get 96s close to that. The 6x-4 should be very close to 9.5. With porting, good induction, and exh, cam can work up at 10 scr on 93 pump gas in a 455. You better really know what your doing if you get close to 10:1.. Jay

Edited by - Corncob2061 on 28 Apr 2020 10:30:13 PM
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Rearwheelmaniac
Tribal Scout

USA
19 Posts

Posted - 29 Apr 2020 :  08:36:07 AM  Show Profile  Reply with Quote
I guess what I was looking for was to disregard chamber size, and shoot for - chamber geometry or flow rate or valve size.
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Corncob2061
Crazy Horse

USA
669 Posts

Posted - 29 Apr 2020 :  2:57:56 PM  Show Profile  Reply with Quote
...... 6X-4.......................,,,,..........96
...... 2.11/1.66....................... 2.11/1.78
Lift.....Int/Exh..........................,Int/Exh
0.1.....89/48............................. 76/50
0.2...141/101. .........................135/95
0.3...175/134...........................177/128
0.4...198/148............................199/148
0.5 ...205/153...........................206/161
0.6...205.155............................210/166
Stock..6X-4 has a gentler short turn radius on the intake, it will flow more below .3 lift. The shorter short turn on the 96 keeps the heads from going turbulent at the higher lifts above .5. The exhaust is about dead even if the 6x-4 has the small exh valve. A 1.77 bumps the exhaust flow up to above the 96.

IMHO, lower compression, 6x-4 is better. Higher compression with more lift the 96 would be slightly better.....

Edited by - Corncob2061 on 29 Apr 2020 3:01:49 PM
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