for those of you that have read some of my previous posts, you know that my RS has some issues. today i went out to see if i could try to correct them. my car makes a LOUD ticking noise and has a loss of power. i already had a shop work on it, and they ripped me off! my plugs and wires are okay, and i replaced the header gaskets and torqued down the header bolts.
i went to adjust the rockers today using the engine-running method, and right away i noticed that about 4 of them were real loose. i attempted to tighten them, and the bolts were already tight! (that shop i mentioned did a valve adjustment a month ago) i couldnt budge them! and the pushrod was rotating around because the rocker was so loose. but there was nothing i could do! what causes that? worn rockers? worn lifters? valves maybe? the previous owner modified that little 305 a lot though, so i have aftermarket (not sure specs) roller rockers, cam (not sure specs) and vortec heads, casting #10239906. are these heads made for a 350?, and is that contributing to my problem? please help and give me some answers. im desperate!

 

Well, you're not going to like this answer.
Get some way to manually turn the engine (not the harmonic balancer bolt) and measure the lash of the valves with a feeler gauge. Measure the clearance as if you were setting the lash on a solid cam motor and get back to us with your findings. This will give you an idea of valvetrain "health". The roller cam engine uses non-adjustable rockers.
If the can/lifters/rockers/valves are ok you shouldn't be able to get a feeler gauge between the rocker and the valve without backing off the rocker if the engine has been run in the last week. This sounds like you inherited a "cam-swap-gone-bad" engine.
Edit: pushrods rotating sounds like this is not a roller cam engine.

 

its the stock '91 305 shortblock.

 

Don't forget to add your words: "the previous owner modified that little 305 a lot though,"

 

so once i take these measurements, how do i correct this problem?

 

If there is excessive clearance (which means that the valve train is not tight at TDC compression stroke) you can pull the rocker & pushrod and check them against one that is tight. If there is no difference then you will have to pull the lifters and probably the cam. This ASSUMES that the oil presssure has been checked to be ok at idle with a gauge. If there is not excessive clearance then the noise problem is probably not valvetrain related.

 

supervisor I think when you said you can not adjust a roller cam you were thinking of a solid roller

You can adjust a hyd roller but anyway it sound like either you have a worn cam lobe or a collapsed lifter. I would first check all of the pushrods for straightness.

 

also check to make sure the rocker studs arent pulling out....tao

 

yeah thats the worst!

 

You said that you couldn't tighten the rocker nuts anymore? Sounds like the studs could possibly be pulling out.

Take off the valve covers and look at all the studs. Actually, if you have a long, flat-edge ruler or something, even better... put it across the studs, and see if any are taller than any of the others. Its an easy way to tell if one has pulled out some.

 

roller cam engines DO use adjustable rockers even if they are roller rockers. maybe not solid rollerlifter, but the hydraulic roller lifters use adjustables.


if you have roller rockers on there already, did you loosen the poly locks(if so equipped) before you tried to adjust them? if so, like previously stated, check pushrod straightness and if the studs are pulling out.

 

Excuse the brain fart. I had Gen 3 smallblock on the brain.
And solid roller lifters, by design, have to be adjustable at the rocker.

 

Not true. At least, not universally true. Many motors, like the Ford FE for example, had their valve lash adjusted by using different length pushrods. The valvetrain itself was not adjustable in any way from the factory. If you needed to change the lash, you used longer or shorter pushrods, because the rocker settings could not be changed.

 

thanks to all for the quick responses. i will investigate asap. im in the military and my wife is 9+ months pregnant, so i dont get all the wrenching time that i would like.i will make sure to update post with my findings.