How do you set the preload on Lifters.?

Question

Chevy 350ci

Answer 1

I also wanted to set mine without having to start the motor on very probably wildly out of specification lash.  The methods are basically correct as already listed.

Tons of extra info and diagrams at

http://www.autozone.com/addVehicleId,117...

Answer 2

Frank, Your going to hear other opinions about this but my 60's and 70's Chevrolet shop manuals explain it this way:

Remove the valve covers and place oil retention clips over the rocker arms at the end of the push rods. This is to reduce the oil from shooting out the hole drilled in the end of the rocker arm. Start the motor and back off the rocker arm jam nut till you hear a clattering sound. Very slowly tighten the jam nut till the noise disappears. Chevrolet recommends continuing tightening the jam nut another 1/2 -3/4 turn. *There is an alternative here. Noted drag racer Bill "Grumpy" Jenkins taught that after tightening the jam nut till the clatter disappears only pre-load 1/8 turn. The reason for this is you'll have an "almost" fully extended hydraulic lifter and it'll be less prone to hydraulic lifter "pump-up" at high RPM.

The first two answers are incorrect as the oil pump must first supply oil into the side o*****e of the lifter to pump the internal plungers up. If you do it their way the plunger in the lifter will be dry and collapsed. You'll wind up with an very inaccurate pre-load. Another thing to consider. When ever you remove a valve cover from a cold hydraulic lifter Chevrolet what's the first thing you notice? All the valves appear to be fully closed. That's because the oil inside the lifters has already blead-off through the side holes. As soon as you touch the starter, oil pressure enters the small side hole of the lifter extending the internal plungers.

Answer 3

on hydaulic cam=turn engine untill valve is closed and tighten rocker untill you cant spin push rod with your fingers yhen tighten another 1/2 turn.

on solid cam=valve closed use feeler gauge between rocker tip and valve stem usually .008 to .020 depending one application

Answer 4

Note that the following procedure is for preliminary adjustment only. Rocker Arms should be adjusted again once engine is running. Also, there is a spring inside the lifter. This is why when you prime the lifters, (in a pan of oil, no pressurization at play) the internal part of the lifter will come up after releasing pressure. This is why the adjusting nut must be backed out at the start of the procedure for each individual valve. The lifter internals will come up, even with the engine off. If this is as part of a rebuild, just install rockers on specified valves at #1 TDC, then the others after you rotate the engine.

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The valve lash adjustment procedure is for hydraulic lifters which are filled with oil either from previous use (old lifters on which the oil has not drained) or from priming before installation (new lifters or old lifters on which oil had drained while removed from the engine).

Crank the engine until the mark on the damper aligns with the TDC or 0 degree mark on the timing tab and the engine is in the No. 1 firing position. This can be determined by placing the fingers on the No. 1 cylinder valves as the marks align.

With the engine in the No. 1 firing position, the following valves can be adjusted:

V8 - Exhaust: 1, 3, 4, 8

V8 - Intake: 1, 2, 5, 7

Back out the adjusting nut until lash is felt at the pushrod, then turn the adjusting nut in until all lash is removed. This can be determined by checking pushrod end-play while turning the adjusting nut. When all play has been removed, turn the adjusting nut in:

1/2-11/4 additional turn (flat lifter)

3/4-11/4 additional turn (roller lifter V8)

Crank the engine 1 full revolution until the marks are again in alignment. This is the No. 6 firing position. The following valves can now be adjusted:

V8 - Exhaust: 2, 5, 6, 7

V8 - Intake: 3, 4, 6, 8

Answer 5

Once all push-rods and rocker arms are installed check for the lifters that are on the low side of the cam lobe, tighten the rocker arm until there is no play up and down. than tighten the nut 1/2 turn.