non adjustable rocker arm noise

[GeorgeG.]

I need some schooling here. Here's a little back story:

I bought my Lightning a while back and I'm very certain I did not have this excessive rocker noise when I bought it. It has non-adjustable Cobra rr's Fast forward to last year...I had to remove one of the heads to remove some debris from a cylinder since I wasn't able to fish it out of the plug hole. I got it all assembled, torqued everything down according to specs and now I have some serious valve train noise on that side.

I plan to pull the valve cover and see if something came loose, other than that, could there be anything else that could cause it? There were not any shims when I removed the rockers either.

[Whiteboy]

ive seen a few sound like rocker arm noise on stock rockers ended up being bad bearing and not getting much oil to the heads

[0393gt]

Did you replace that head gasket? If not, its gotten too smashed and gave you the extra space.

[GeorgeG.]

yeah, new head gasket. I haven't pulled the cover yet due to todays gun gathering.

[blownragtop]

I have a 93 Lightning with the same Cobra roller rockers. On my truck’s heads the factory holes were not tapped completely so the supplied bolts were bottoming out giving false torque readings and not allowing adequate lifter preload. Retapped the holes with a bottoming tap and problem solved. Might want to check the end threads of the hold down bolts for signs of gnarling/damage. The previous owner may have over torqued the bolts to resolve this.

As an aside - GT40 heads installed on Cobra's went through an additional milling operation to raise the compression ratio. When you are dealing with a non-adjustable valvetrain little things like gasket compressed height and deck thickness begin to add up.

[GeorgeG.]

Thanks for the info, I'll definitely check this out.