hdtvned

I have a SBC 383 with hydraulic roller lifters, mild cam, roller rockers, stud girdles. I think I know the basic procedure, get the cam on its heel or base circle, spin pushrod while tightening adjusting nut, when resistance is felt stop then, tighten X amount of turns.
My question is how much resistance should be felt and then how much to tighten them. I have been told anywhere from 1/8 - 1 full turn.

Vinny P

I would call your lifter manufacturer and ask them how much preload they want. Generally, 1/2 - 3/4 turn is good, but ask them to be sure.

Ryan00TJ

iTrader: (8)

When you feel a slight resistance to the turning of the pushrod you are at zero lash. I would echo checkmate's idea to call the manufacturer and get their take on it.

What are the specs on your 383?

BillK

hd,
I dont like telling people to "turn" the pushrod until they feel resistance. On some new lifters, if your fingers are strong enough, you can go all the way until they bottom out before you feel any significant resistance.

I prefer to tell my customers to "jiggle" the pushrod up and down until you just get all of the free play out of the system. Then crank in your preload.

If you have not done many, its much easier if you do it before you put the intake manifold on. That way you can actually look at the lifter and see when you start to move the inner plunger.

Hope this helps,

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Ryan00TJ

iTrader: (8)

BillK, I like that idea. Jiggle it! I can see where it would make it easier for someone who has not adjusted valvetrains alot.

hdtvned

Cranes specs are .020 - .060 or from 1/2 to 1 full turn. Are these things that forgiving ? Last year I started with 1/2 and they were noisy at idle. 3/4 shut them up.
The jiggle the pushrod tip makes sense to me. I may be driving myself nuts over nothing. I wonder how much of the engines oil pressure is actually available to the lifters plunger vs the valve spring.
In other words is there enough to hang a valve open ?

the duke

You are fine. one turn is usually a bit much. I try for 1/2, and I've not had any problems.

When you check them, you have to make sure that the valve you are checking is 100% closed. As you go through checking them, the lifters will bleed down some, so you don't want to push them down too hard, or you will have them set too tight. The "jiggle" usually works very well.

I don't know what you mean by the difference between the oil to the lifter and the oil to the spring. The lifter is pressure fed. The spring is not. It gets the oil thats pumped up through the pushrod, so its an oil bath, not pressure.

mrhorsepower1

The correct sequence for valve adjustment is follows:

1.) Adjust Intake valve when the exhaust valve just begins to open. ( approx. .030 or so of the seat)

2.) Adjust Exhaust valve when the Intake is almost closed. (approx. .030 or so off the seat as well)

On Hyd. cams ( flat or roller) to properly set preload you will slowly adjust play out of pushrod. You can do this by spinning and jiggling pushrod as prior mentioned, as soon as you feel no play stop and I put a 1/2 turn preload into the lifter. 3/4 turn max

If you are running roller rockers on the engine you will want to lock the polylock with both the inner set screw and the hex adjusting nut. This will prevent the polylock from loosening. Do NOT lock with set screw only!

BillK

hd,
The lifter will definitely pump up and hold a valve open ..... if you get into valve float. That is what a hydraulic lifter is designed to do, take up any extra lash in the system. It is fairly rare in most lower rpm applications but it can happen. That is why most performance cams specify a small preload, 1/8 turn or so. That way if the valves do float, the lifter can only pump up a small amount. I would venture to say that in most marine applications it is not a real big issue. I generally go with 1/2 turn and have never had a problem'

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

hdtvned

Thanks all for the advise. It now makes sense, better yet it is done.
Again Thanks,
Ned