on a 350 chevrolet, how easy should the pushrods be able to turn with your thumb and finger while the valves are closed. the engine is around a 75- 76 if that makes a difference, and the cam is stock. should they turn freely, or have a little resistance?? thanks, Art
also, should there be any play in the rocker arm? should I be able to move the rocker arms around, like side ways at all?
If the valve is closed back the rocker off to no play (or tighten it) then give it another 1/4 to 1/2 turn. When properly adjusted if you have fingers like Jim or me, you will be able to turn them but your hands may not be that strong. I know that my wife could turn mine when they were adjusted properly, she often checks my work and has since we were kids, but young engineer that she works with wasn't able to do so.
thanks guys, there is alot of play in the rockers now. kinda like a solid lifter or even more. would this cause the backfiring, and hard to start, and no power on exceleration??
If the valves are all out of wack adjustment wise it can do all of those things. Def a loss of power and would make a hell of a racket.
As hyd lifters flatten and wear out it shows in the push rod slop as well. I always set them to where they spin in my fingers and then 1/4 turn to set them in the hyd lifter travel. Make a couple of passes with the wrench. Obviously doesn't apply to solids. Backfiring and power issues sounds like timing issues, valves need to be properly adjusted to set timing though. Also make sure you aren't 180 out.
I never worry about whether or not I can spin them. I set hydraulics so the rocker just does not have any slack, then usually half turn preload on the nut. On chevys, that is.
The question to me would be why so much lash (so loose) ... If it is a high mileage engine the lobes may be starting to wear off of the cam, and t hat will cause backfire , power loss etc.
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