The Stovebolt Site Forums The Shop Area Engine Shop Thouroughly Confused (valves, lifters, rockers, blah, blah...)

Hey Folks,

I am working on a 235 from my '60 GMC to go into my '53 GMC. I have been searching the forums and now quite confused. With the help of a fellow 'bolter, the engine has been overhauled. Now I'm at the valve setting part. I lapped the valves and now the head is back on the engine. I was searching through the forums for the valve lash setting.
So first question, what is valve lash? I assumed that was the distance measured with a feeler guage between where the rocker and top of valve meet. Am I correct?
Second, at what point do you set that? Is it at TDC of the first piston? Cause with each rotation of the crank the valves are all over the place.
Third, I thought I just had standard solid lifters as the truck engines did. After my search, I am starting to think I might have hydraulic lifters from this here, "The top of a hydraulic lifter reveals a cup shaped disc held inside the lifter bore by a small snapring." My lifters didn't fall out when I flipped the engine over (as my 'bolter friend said they would). I could not lift them out and just considered myself lucky because that was one less thing to organize.
Fourth, I also read, "Tighten until the pushrod will not rotate, that will start the engine and then you can set the valves as its running." Is that the proper method, or should I use a feeler guage and measure "it"? (for lack of better word).
Whew, Thanks!

The young grasshopper,
Colin

Searched Here. here, and good stuff here.

1. Right! Valve lash is the distance between the rocker and the valve in closed position.

2. You have to set the valve lash at the power stroke at every piston, when the valves are closed.
That means you start with - lets say - 1(front) and then 5,3,6,2,4. You have to rotate the crank every time.

3. Make sure what lifters and what cam you have.
The cam card tells you the lash (mostly different) for exhaust and intake. For hydraulics there is a different approach - they are set to zero lash.

Here click is more than you ever wanted to know about valve setting and a step by step tutorial.

Have fun, Frank

"untill the push rod will not rotate" is too tight. when the engine as oil presure the hyd. lifters extend.
easy way to find top on any given cyl. when the rockers are switching from intake close and exhaust open, the opposite end of the firing order will be at top fireing point.

I am sure there is a tech tip somewhere on adjusting hydraulic lifters. Anyhow, if yours are hydraulic, you will want to follow the tip for hydraulics, not the one for solids.

What exactly do you mean by, "the engine has been overhauled"?

Thanks for all the info guys!

Frank, wow thanks! Where might the cam card be?

Richard, I mean that it has been diassembled. Everything but the cam and the crank removed. Then we measured the cylinders, crank (main and connecting rod), installed new connecting rod bearings, cleaned it all, painted it, lapped valves, assembled most of it, and now i'm trying to figure out how to set it all. With the measurements made, and the condition of everything, it appears to have been rebuilt about twenty thousand kilometers ago. It has a 6 thou bore, and ten under crank grind.

Chester, that could be a potential easy way to find TDC. What do you mean by "the opposite end of the firing order will be at top fireing point" ? So 1-5-3-6-2-4, when the exhaut valve opens on say piston #1, piston #(edit: I was going to say #3, however i'm wrong, and don't know what it might be)is TDC?

Thanks!
Colin