Thread: Valve adjust on Small Block 350

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Just a short question:
supposing the engine has been run before, then how can I be sure that zero lash isn't already a bit further down than the fully expanded position of the lifter? In use, the lifter compresses a little bit and stays there. Do all hydraulic lifters have springs in them to decompress them as soon as the pressure exerted by the pushrod is gone?
How would I set the lifters in an engine that has been run, lifters full of oil, but I don't want the mess? Is that possible to do correctly without the engine running?

MadMax here is what we experienced.

All the lifters were not compressed, they where all extended, (full length). This is because of the springs in them, I believe.

When we tried to compress them they would not compress at all, not in the least bit!! The associated valve just opened. This meant we really couldn't discover the "lifter piston stroke". We shelved that idea and instead used the method by which we rotated the pushrod until it stopped turning (very obvious point) then added one turn. You have to be a little careful because this whole '1-turn' results entirely in the the valve projecting into the cylinder. You could have a valve ram a piston even with the engine not running. So if you feel a sudden increase in pressure while adding the turn STOP! note where you are and come back in 10 minutes for the rest of the 1-turn.

With number one at top dead center we were able to adjust all but 6 valves. We then turned the engine 1-revolution and were able to do 5 more. Then we turned the engine another few degrees until the last lifter was obviously down and did it.

What we discovered MadMax was that after about five minutes all push rods could be easily rotated with the fingers again. So they will leak down. Of course this means you need to be kind of time considering when adjusting the valves. If you take 5 minutes to creep up to the 'pushrod-doesn't turn, zero-lash point' that one valve WILL NOT actually be set to 'zero+1-turn' but will be more than one turn!

We may be turning the key today. I'll let you know how things work out.