comp cams 68-232-4 with pontiac springs

[kptuck]

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I have been on the hunt for some springs and retainers for my stroker to rule out possible valve float.  The easiest solution I have found is running pontiac springs out of a 94 - 2003 grand prix.  The pontiac springs are beehives and the valve stem is the same diameter as the Jeep stem.  The only issues I am encountering is running the Jeep 7 degree locks on the pontiac 8 degree retainers.  Has anyone done this and do you think it might cause a problem down the road??

I tested the pontiac springs at 1.650 which is the installed height with the set up.  The results were 95 lbs, so I tested at my open height which is 1.117 and the pontiac springs rated 255 pounds.  I called summit for specs on stock pontiac springs and got a spring bind number of 1.065 (i think)  I can verify this number in the morning. 

These beehive springs are in a ton of GM vehicles and I bought all the springs and retainers from pick n pull for $4.00.  I have access to high-end testing equipment so I was able to grab a couple extra springs and throw out the lowest pressures, but they were amazingly consistent.

Another observation is the the spring ID is rather tight on the stock Jeep head spring seat.  It goes on just fine, but you have to push it on, it doesnt sit loose.

Again is this an issue? does the Jeep engine count on the springs rotating at RPM or just the retainers?

Thanks

[dwg86]

The jeep locks are 8 degree. If you look up the mopar performance locks for the jeep 4.0, they say 8 degree.

[kptuck]

my mistake, I was up at 1:30 at night trying to post and switched the two numbers. The Jeep is 8 degree and the Pontiac is 7 degree. The question is if running the 8 degree locks in the 7 degree retainers is going to cause a problem? Sorry about that.

[gonridnu]

I believe LS1 valve locks are 7 degree locks and utilize the same beadlock style as the stock 4.0 valves. They do move the retainer up the valve about .015" which is easily compensated (if even needed) with a valve spring shim and still leaves enough of a valve tip protruding for the rocker to run on and not hit the retainer. That solves the lock problem nicely...

I have assembled many engines in the past where the retainer to spring is a tight "snap fit" and had no issues. That however does not mean it was correct. I recently saw some slow motion film of a valve spring and retainer done on Comp Cams spintron facility. The retainer when properly fitted with some clearance actually rolls around on the top of the spring. It's kinda like a quarter does when you spin it on a desk in the final moments before it stops and lays flat. This leads me to believe that interference on a retainer is a bad thing as it would not allow that motion to occur and would inhibit rotation fo the assembly.

That being the case I would have to say that interference at the base of the spring is probably not a great thing either. While it would likely "work" and not cause immediate issues the concern would be that it could not rotate, as you stated, and that the interference could create some heat that might lead to failure and there might possibly be a harmonic issue. Still I think it would probably go unoticed in our application.

I am very interested in what you have found. The spring rates sound very usable and possibly are even moreso with the LS1 keeper's slightly taller installed height. Machinng a little off the spring locater is not a big deal fro someone that is doing a ground up build....

[gonridnu]

I'm texting with a guy that is way smarter than me....he says if it is only one coil that binds and it does not scrub material off it should be OK and the spring will still try to rotate when the coils expand under compression. Multiple coils will heat up as they rub up and down the locater. He also said that if the spring cannot rotate it can lead to breakage. Sooooooo... how hard do they snap on the head and how many coils?

[kptuck]

OK, thanks for the input.

This morning I measured the "stock" 98 single groove locks for 8mm stems that I have on my Jeep. They came out as .465 on to and .395 on bottom. This corresponds with the LS-1 retainers very well which measured .470 top and .400 on bottom which should let the retainer move up a little as you stated.

SO, I installed the Pontiac springs and retainers, and used my "stock" locks. I torqued everything to specs and started the engine with the valve cover off. It took a few moments for the lifters to pump up and then oil started flying, which I was prepared for...

There is no additional noise so I installed the valve cover and started it again to let it warm up. Once warm I put it in low range and drove it around my shop at 3000 RPM to let everything "seat". I was nervous that I was going to have an issue. I then floored the engine and it ran up to 6000 RPM without missing a beat.

Feeling a little victorious but still nervous I drove back into the shop and pulled the valve cover. Retorqued the rockers and inspected the locks and retainers. Everything looks good. The valve train is quiet like before but I now have higher spring rates that let my cam work.

The Sealed Power direct replacement springs for the Pontiac I stole the springs out of is SLP-VS-1642.

The specs are 72 lbs at 1.70
233 lbs at 1.260
Bind at 1.065
330 lbs/inch

Mine installed at 1.650 with 95 lbs, and at 1.177 I have 255 lbs, according to the test equipment.

The spring definetly only has one coil touching the inner spring purch and though it is not easy to spin I beleive it will after a few miles. It pushed on with the effort from 2 fingers so maybe 5 - 10 pounds.

[gonridnu]

Just to be clear, what lock and retainer did you end up using? I'm on this like flies on.....uh.....a picnic:)

[kptuck]

I used the retainers and springs off a 97 grand prix. I used my locks off my 98 Jeep 4.0 0331 head.

The locks are suspect as I have had a head job done, so I measured them and tested the fit with the retainer against the stock pontiac locks and they are identical other than being single groove Jeep valve locks.

I now hit 6000 RPM and have no issues. (yet) Use this info at your own risk

[lil_red_wagon]

Do you know which valve spring it was in the 3.8? I'm showing 2 different ones available. I'm tryin to find the right one. Napa is the one showing 2 diff ones. Here is a link to them. http://www.napaonline.com/Search/Result ... 60+2060016 It actually shows the 3, but 2 of them are the same. I have access to some from a 95 Olds 3.8. I'm just not sure if they are the same one. The olds is showing a few differant springs which some are the smaller one of the grand prix. and some are even smaller.

[SilverXJ]

The SLP vs-1642 crosses over to the 3.1L and 3.4L engines, not the 3.8L engine.

Do you have the part number for the retainer you used?

[SilverXJ]

The GM part number for the retainers is 10166344. My machinist just put a set on his Dodge Dakota 5.2L head. Basically the same setup as ours. He did have to grind the inside of the few lower coils to get them to fit over the protruding head part. IIRC their cost was around $200 for the retainers and springs.

[lafrad]

Grind the COILS?!? as in, grind the SPRING to fit the head?

That sounds like a recipie for coil bind and all sorts of valvetrain failures. MUCH MUCH better to machine the head so the cast iron gets outta the way of the untouched spring.

[SilverXJ]

Grinding the inside of the coils slightly won't hurt anything. Don't see how that brings about coil bind. But, you are correct, its best to cut the head.

[lafrad]

Well, when the coil compresses, new pieces of steel are now lower and closer interfering with the cast iron head.

ALSO, grinding the spring steel weakens it at that point, causing the spring rate to be inconsistent and out of spec. I realize its minimal, but, spring failures are so catastrophic that I would NEVER take a chance with it.

[redrider2911]

I was planning on using the 3.8 springs but then also noticed that the part number given crosses to the 3.1 and 3.4, not the 3.8. Can anyone else verify this setup?

Kris