SPDEMON

Hey guys,

I'm having a bit of trouble with the poly locks on my pro-form rocker arms loosening up after a few hundred miles. I Finally (after 400 miles break in over a span of 2 or 3 weeks) ran the new motor up to the shift point (6500) rpm, and now can hear what appears to be a loose rocker arm.

I had an issue with the engine builder leaving one valve unadjusted and it sounded just like this.

I've heard that the Ultra Pro Mags are the best.

I would prefer if these were to fit under a stock valve cover.

Can anyone confirm that they will either fit or I'll need custom covers?

93M6Formula

Yes they fit just fine. The only thing you have to do is trim the brace inside the cover that spans from side to side, but only the one towards the intake.

96capricemgr

iTrader: (1)

Why not fix the problem you have? The problem is not the rocker, maybe the polylocks. How are you tightening? Most of us go to zero lash, then say 1/4 turn(to endup at 3/8ths) on the nut, then lightly seat the lock, then give the lock and nut together a little more turn. Adjust how much preload to suit your wishes but basically preload the nut a little less than you want and do the final seaing together.

ProMagnum rockers need the stock covers to be trimmed a little bit, after that they fit. Really a minor mod.

SPDEMON

I went zero lash, 1/2 turn, plus another 1/8-1/4 turn on the lock. After doing some research on LS7 lifter pre load, I'll probably go zero lash plus 3/4 turn followed by another 1/8-1/4 turn on the poly lock.

The other reason is because they seem to be kind of noisy even when they are fresh off an adjustment.

However, I have also been reading that the LS7 lifters have had some failure issue in regards to the plunger collapsing. I noticed on the last adjustment that a couple of the valves seemed to have less pre load play that others, but I assumed it was due to the relation of the cam lobe at the time.

So I'll probably try one more time to adjust them, but after that, if I have any more problems, they're getting swapped for pro mags.

camar0corey

iTrader: (22)

I had just trimmed the braces down a bit for the promags, after this last rebuild I had to actually cut the upper bracing out for the ultra promags, they were beating the hell out of the upper bracing for some reason in my case.

Some days I really do consider adjustable guide plates.

SPDEMON

Yeah, I hear you man. Sometimes these self aligning rockers just don't seem like the best idea. Failure looks to be more catastrophic than with guide plates.

So I just got my ultra pro mags yesterday, guess I'll have to trim the valve covers. So fun! Lol. Fml.

BALLSS

a dremal with a cut off wheel makes very quick work on VC trimming of braces

96capricemgr

iTrader: (1)

Less time and less grit involved with simple tin snips.

SPDEMON

Good call, I was going to try that first and see if that would work before using a cutting tool that will make a mess with shavings etc....

chaney1974

I just got the pro magnum rockers and how much did you turn the locks past zero lash? I am at 1/2 turn and still have lifter noise? as for my valve covers I just flattened the brace and they clear now

shbox

I think the LS7 lifters are just noisy.

Fast355

^^^ Very real possibility

I am worried that I either have one of the bad comp cams or maybe just have noisy LS7 lifters. I replaced the stock lifters in my L31 with a set of GMPP LS7 lifters when my 215/220 @ .050 Comp cam went into my L31. Its been in there about 6,000 miles and my engine sounds like it has slowly been invaded by gremlins with ball peen hammers. It was very faint and has gotten progressively louder. I checked the valve lash not long ago and it stayed more or less the same. I have had Crane gold 1.6s on it for the last 30K or so and they have always been trouble free in adjustment and barely noticeable to me.

SPDEMON

It depends on which lifters you are using. If you're using LS7 lifters, or another lifter with very similar plunger travel depth, you can go 3/4 of a turn.

But, it does seem like LS7 lifters are pretty noisy, unless my fuel injectors (trickflow #30's) are making noise...

ACE1252

I have ARP polylocks and stock LT1 lifters(ordered from GM around 5 years ago).

I set the preload to 1/2 turn after zero lash. After the 1/2 turn preload, held the polylock in place with a boxed end wrench and tightened the center allen screw, with a socketed allen bit, to 30lb-ft. Don't move the boxed end wrench when tightening the allen.

I have not touched them in over 5 years. No trouble at all with polylocks coming loose.