Hey guys,

We built an '05 GTO with a built engine, L92 heads, 76 intake.
We used the stock rocker arms that came with the L92 heads and the stock rocker bolts.
The car has a mild cam, lower compression than stock and a procharger, 600+hp.

About 2 weeks after the engine was running fine, #2 intake rocker broke and I just wrote it off as a weak part. Now 3 weeks later, #6 rocker arm bolt broke.
Nothing sounds consistant about what parts are breaking and all clearances are right.

Anyone else have this issue? Should I just assume the bolt was weak or maybe reused too many times?
It broke off in the head, so that sux!

thanks,
allen

edit: are there any stock rocker arms I should go for, I know there aren't any bolts available from ARP?
thanks again,
allen

 

if it was me, i would start to suspect something isnt aligned right...
as for how to check that rocker arm alignment.... ya got me...i donno. but its the same head for both... maybe the rocker holder pedestal strip isnt in the correct position?

 

I'm not sure how to align it, everything is stock replacement. The rockers just sit on the head and you torque them down.
Wear pattern on the valvestem looks good, nothing hitting the valve or rockers, hmmmm.

any suggestion would be appreciated!!

allen

 

And you are using the L92 rocker supports?

 

over tq on the bolt can cause this, and a bent pushrod/valve can also be suspect.
good luck

 

Agreed, you need them if they aren't on there.

 

The L92's are the only supports that will fit, so yes, they are on there.
If were talking about the same part, I don't think it would run, right, lol?

I checked for a bent pushrod, it's still good.

Maybe just a bad bolt. Hopefully it stays together.

Are there any aftermarket rocker arms available?

thanks for the input guys,
allen

 

Are you using factory valves or after market? The reason I ask is GMHT had a article where they found the after market valves required the valve guide to be enlarged slightly because of too tight of fit. Said it could bind if gotten too hot. This could cause the problem you have. The article was on L92 heads on a GTO & things they did to the heads before assemble.

 

Ya, we checked that. I think that was an issue with camaro valve covers, the LS2's are ok, at least on this car. Thanks for the suggestion though.

The car is running great, again, we'll see if it holds up.

This happening just makes me think there might be something going on. Two different issues, both related to the intake side.

thanks,
allen

 

I got my L92 rockers upgraded by Harland Sharpe and they included new bolts.

I believe they are grade 8. Maybe the new style bolts will help.

Bob K.

 

great, do you have pics or pn's? i'll get some.

thanks,
allen

 

Send a PM to Nasty N8. He can get you the info that you need.

He sets up the transactions with Harland Sharpe. BTW, everything went very smooth for my rocker upgrade.

Bob K.

 

Are you using a stress gauge while you torque down your bolts?

We just got a sprint car engine in our shop, and the previous engine builder never used one, so he wasn't getting the correct tq reading on his rod bolts. Engine blew up twice this season for the same basic reason. Bolt torque failures.