Question about vavle train geometry and rocker shaft buttons

[robk46]

New engine with 100 miles on it. Wiseco .020 forged pistons, new Sealed Power lifters and 204/214 cam. Stock pushrods and rocker shafts. Making valvetrain noise up top, louder at idle speeds with no load than in gear. You can barely hear it in gear.

1. The heads were shaved .008, do I need to measure anything?

2. Some of the rocker shaft buttons are loose. I can wiggle them in the hole quite a bit, would this cause a noise?

The car runs great otherwise. No popping or stuttering when accelerating. 15lbs of vacuum in gear at idle, 25PSI of oil pressure in gear at idle with 10w30 oil.

This is only my second rebuild, and I'm really nervous. These cars can really stress you out.:frown:

 

[MSDGN]

Well you have a different cam and the heads were shaved...and you're using stock pushrods...you need to get a pushrod checker...measure...and get new pushrods the correct length...you want about .030-.040 preload on the lifters...other option is to get adjustable pushrods.

 

[robk46]

How do you measure preload?

 

[robk46]

Found a link. Lifter Preload

What about the buttons? Should I just replace them if they're loose?

 

[MSDGN]

There are a few ways...but I prefer to use a pushrod checker...can get one from Comp Cams...not expensive...the pushrod has calibrated marks on it...I think each full turn is .050...so you take the checker...insert between lifter and rocker...unscrew it...keeping track of how many turns to get to zero lash...which is when the pushrod won't go up or down anymore...then unscrew it another .030-.040...keep track of exactly how many turns plus any partial turns it took to get there...screw it back down...remove it...unscrew to same point...that's the length pushrod you need...you could also get adjustable rockers but may still need new pushrods...do a search to find other ways to measure preload...as for the buttons being loose...that's not right...they should not be loose in the holes...if you're going to continue using the stock rocker shaft I would replace the buttons...they should go in real tight...I had to tap mine in with a hammer...

 

[robk46]

Will this one work?
http://store.summitracing.com/partdetail.asp?part=CCA-7703-1&autoview=sku

 

[robk46]

Would .008 inches really matter that much?