LT1 rocker arm question

[AI#97]

Those that have stuck with the LT1, I have a question about rocker arm adjustment...or more specifically, the lack of FIXED adjustment.

1. So this engine that Glenn built has about 45 hours on it and it is still putting out numbers within 10hp of what it did when he first dyno'd it. all good there.
2. I did have to put a new set of lifters in it as it ate a lifter at about hour 3 in it's life very shortly after we bought the car.
3. Glenn liked to run the valvetrain rather "loose" for my taste. say 1/4 turn or less of pre-load if I were to estimate it.
4. I prefer 1/2 to 5/8 of a turn of preload as it keeps the valvetrain quiet and much less chance for problems.
5. Lately, I've found that the rocker nuts aren't holding their settings for more than about 90 minutes of run time and backing off to nearly ZERO pre-load. PROBLEM.

So, I found this as a two part problem. first by chance while chasing a valve cover leak and two as false knock that sends the computer into limp and pulling 20 degrees of timing.

It is too late to switch to roller rockers for ECR...(rules question anyway though I've seen ford guys run them and I know tall valve covers have issue with the alternator)...so I'm left with finding new rocker nuts and running the valve train for the 4th time in as many months of running the car in fun events...this is getting old. What have you guys done to end this issue or have you just not had the issue?

Gracias. See you guys at ECR...noisy valvetrain and all. yeeeehhaaaawwww!!

[Supercharged111]

Yeah roller rockers aren't gonna happen. I set mine at a full turn of preload in 2015 and haven't looked back since. You either need replacement studs or better nuts. Or try some poly locks on stock rockers?

[AI#97]

Yeah roller rockers aren't gonna happen. I set mine at a full turn of preload in 2015 and haven't looked back since. You either need replacement studs or better nuts. Or try some poly locks on stock rockers?

I put some new nuts on and things got quiet. I am sure there is some wear on the studs that isn't helping.

Why a hard "not happening" on the roller rockers?

[Supercharged111]

I put some new nuts on and things got quiet. I am sure there is some wear on the studs that isn't helping.

Why a hard "not happening" on the roller rockers?

Because the stock stuff works fine. Roller rockers are an added expense. If we had guys all across the country galling rockers and nobody could get them to hold an adjustment that would be different.

[AI#97]

Because the stock stuff works fine. Roller rockers are an added expense. If we had guys all across the country galling rockers and nobody could get them to hold an adjustment that would be different.

Hmmm, are ferds allowed to have them? What about longtubes on an LT1?

[Fbody383]

What about longtubes on an LT1? Another no. Factory manifolds only. Still restricting from there anyway...

// or someone will correct me //

[Supercharged111]

Hmmm, are ferds allowed to have them? What about longtubes on an LT1?

The 5.slows can as the Cobras came with them stock, but they need to be the factory correct type. Only stock manifolds need apply for the LT1. There's no point in opening that up as they need to be restricted anyway.

[RichardP]

If only there was a place you could go to get all these answers yourself...

Richard P.

[AI#97]

If only there was a place you could go to get all these answers yourself...

Richard P.

You do realize coreys 4th Gen had long tubes right...?

[AI#97]

The 5.slows can as the Cobras came with them stock, but they need to be the factory correct type. Only stock manifolds need apply for the LT1. There's no point in opening that up as they need to be restricted anyway.

I keep restricting and lowering hp but torque stays North of 317.59avg. Soon will be in the 240's and have illegal torque so looking for other ways to get hp... But kill torque. Short of cutting a custom cam.... Lol!

[Supercharged111]

I keep restricting and lowering hp but torque stays North of 317.59avg. Soon will be in the 240's and have illegal torque so looking for other ways to get hp... But kill torque. Short of cutting a custom cam.... Lol!

We did bump the start RPM for Dyno pulls to 2500 in case that peak number is right at 2000 when you crack the gas.

[AI#97]

We did bump the start RPM for Dyno pulls to 2500 in case that peak number is right at 2000 when you crack the gas.

Yeah, that isn't helping! LOL!

Has anyone ever done a scientific "area under the curve" assessment of each engine type and posted it?

[marshall_mosty]

You do realize coreys 4th Gen had long tubes right...?
Cory's car (previous Matt's) never raced in legal CMC trim so the long tubes were never an issue. It obviously would need to be converted prior to racing for points/contingency.
Any quasi-legal car can "fun run" just to shake down while the driver gets the non-compliant issues sorted.

[AI#97]

Cory's car (previous Matt's) never raced in legal CMC trim so the long tubes were never an issue. It obviously would need to be converted prior to racing for points/contingency.
Any quasi-legal car can "fun run" just to shake down while the driver gets the non-compliant issues sorted.

We fixed that issue...that car got cut up and parted out. It will never offend anyone again. ;)

[michaelmosty]

We fixed that issue...that car got cut up and parted out. It will never offend anyone again. ;)
It never offended anyone. IIRC it only ran one event as a fun-run many years ago prior to Cory owning it.