Looking at the rods that are still in there, they are very close to the bottom of the hole. On the holes of the two that I removed they show no sign of be out of round. As far as I can tell.

 

.12 difference. Is that 1/8?

That sounds like head removal.......If I'm doing that I'm just going to get new heads.

 

Would it make any difference with this spring issue if I put the the OE rockers back on? Or is it not worth fooling with? Just a thought.

 

I personally don't think you have a spring issue, would look elsewhere.

 

Thanks, I'm just trying to cover all the bases on my way down to the opti and then timing gears.

 

Not nescessarily. Don't panic yet. I'll let you know when it is time to puke
In the old days, chevy motors has an exhaust rotator installed. When it was removed, there would be a ton of space to make up with shims.
Although I have done many small block chevy heads, but I have not personally done a set of LT1 heads. I doubt there is a rotator, but who knows.

Anyhow, .125 is 1/8 inch, and you should not have more than .010-.020 from any 1 spring height to another (typically, much less).

If you truly have 1/8 inch difference, the first question is why?
Are the spring seats different thicknesses?
Is the thickness of the retainer different?
Are there shims under the seats on your head?
Normally, all retainers are identical, all seats are identical, and the shims are near identical.

If the retainers and seats are all the same, and there are no shims under the seats (or an equal thickness shims under each seat), then you have a problem.

As far as people telling you to look elsewhere, it sounds to me like you definately have a problem.
You have a cam than needs about 125 pounds on the seat, and you are likely at about 175 or more, based on the 1.78 height.
How much pressure can a hydraulic lifter take?
Depends on who you talk to. I have never run more than 150 pounds, because of fear.

It is certainly safe to say you have a huge amount more than you need (spring pressure).

 

Nope, no rotators on LT1 heads.

 

the only difference it would make is less power since the stock 1.5 rockers result in less lift at the valve than the 1.6s you have.

A bad opti doesn't drop 50-60hp without other noticeable symptoms...ie a really poor idle, missing under even light to moderate load, etc.

I think you need to re-measure the springs. A difference of 0.012" would be more believable and acceptable. A difference of 0.12" means the machinist should receive a pink slip And yes, .12 is nearly 1/8" (which is .125 ).

If you have a scanner that can record data and export to Excel (ie Autotap, etc), look at the knock counts and timing retard. I doubt you'll see much of either but you may see some. That alone won't explain the why the power is down to the levels you're seeing.

I'm going to guess the cam timing is off or the cam is toast as Pete suggests above.

Edit: One more thing....check and double check that the plug wires aren't crossed. Unlikely, but worth checking just in case.

 

[QUOTE=96GS#007;1572143175]


I think you need to re-measure the springs. A difference of 0.012" would be more believable and acceptable. A difference of 0.12" means the machinist should receive a pink slip And yes, .12 is nearly 1/8" (which is .125 ).

Worse than that, they are stock heads. It has to be a mismeasurement of the height, or the valve has receeded into the head big time.

 

Pretty sure the heads are stock.

 

I personally think the reason LE suggested I use these springs was because of future head work he was going to do for me. He was just trying to save me some money down the road. I want to get new heads this spring, probably AFR's so I most likely I won't need these springs for them.


Pete, my point is, can I just install springs that are in line with the pressures I need for the stock heads I have now and that will eliminate this issue as being the problem. If it's still there after another set I can proceed to look at other parts or the installation of other parts as being the issue.

I just need to know which springs and seals to buy to meet this seat pressure. I looked at Comp Cams site but all they have are beehives for the LT1. I would prefer a double spring just in case one breaks on me.

 

As far as I know they are. I would have thought the rwhp with the OE PCM would have been more if they weren't. 268 I think it was.

 

[quote=Pete K;1572143226]Ok, tomorrow I will remeasure just to make certain.

 

Sure you can. The question is what is your installed height? Height, and spring rate determine if a spring will be acceptable.
You need to know that and the od of the springs that fit your heads.
Then, you need to know the max lift of your cam.
With the above info, you can best determine which spring best fits your needs.
Don't let it overwhelm you. I know it is confusing, but valve spring set up just math. After the first couple of times, it gets easier.
Have you figured out what the discrepancy was with the 1/8 inch difference in installed height?

 

There are many on the CamaroZ28 forum running the same springs on stock heads/lifters as advised by LE. I have yet to read a problem with this setup from any of his customers. Rick Reeves on this forum is running practically the same camshaft and springs.

 

MATH..........not my forte. This gauge is marked in .50 increments so anything inbetween is a guess on my part. Perhaps I didn't tighten it up enough on one or the other. I will redo it tomorrow and try to do it the same on each one.

 

This is different. The OP has a huge problem he cannot figure out as of yet. To not check something because some others dont have the same problem would not be very responsible.

If something checks good, it can be crossed off the list, and move to the next item.

While everything you say above may be true, engine builders I work with would not run spring pressures that high. When we discuss it, they say "why the hell would someone put that much pressure to it?
Kinda like running 50 psi in a 35 psi tire. Who cares if it doesn't blow up? Why take the chance.

Anyhow, I did not post this to be combative in any way, so don't take it as such.
Mike has a problem, and it has always been my position to troubleshoot down the list. That is what I am trying to do. To sway him away from a possibility because the rumor is it works for others shall not help him.

 

The one I have is marked in .001 incriments. I wonder what one you have?

 

No offense taken Pete.

 

Thanks man
I do agree that it may not be "the" problem. I meant no offence as well.
I just wish I was closer to Mike. I actually enjoy degreeing a cam, and valve spring set up. Once you get the hang of it, it is easy as pie.
Pretty sure if one of the 2 was his problems, I would figure it out quick.