[Rugratman]

I have heard this two way's, when tightening a cold engine lash.

#1 Turn the nut until the pushrod will not spin anymore in it's seat, basically finger tight nut.

OR.

#2 Turn nut so that the push rod will not travel up and down anymore, but still spins in it's seat.

Which way is correct?
Hydraulic cam.

[Tom Vaught]

Up and down

Lash is "clearance"

Torque required to eliminate rotational movement is a different story.

A hydraulic lifter only has a given amount of travel of the plunger in the mainbody. Finding zero lash and then 1/8th turn will put the plunger near the top of the travel. Setting the plunger based on no rotational movement will put the plunger at the lower end of the plunger travel if not making the lifter act like a solid lifter with no lash. Not good.

Solid lifters are set based on a cold setting by some smart tuners with an expansion rate developed over time due to temperature changes.

Tom V.

[goatmanmitch]

As I recently found out, making them too tight leaves the valves partially open resulting in poor compression, hard starts and very low power. That was when I learned that you don't tighten them until the pushrods either don't spin or spin with a lot of resistance.

[Rugratman]

Maybe I am doing something wrong.
I set them barely finger tight, as so the push rod has no up and down at all. Then added 1/2 turn on the nut's.
I am still getting a chatter out of them.

90 degree meathod of setting lash in order. Per Mr. Hand
Should I maybe do them one at a time? Hot vs. cold.?

[ChadH]

When I set mine I was twisting the pushrod until I felt a little resistance, then went 1/2 turn. Seemed to work perfectly. I too was wondering was the actual term/definition was!

[Schurkey]

If we're talking about hydraulic lifters, and the preload adjustment is by tightening the rocker pivot nut...DO IT WITH THE ENGINE RUNNING.

Almost impossible to screw up that way.

It can be kinda messy.

[johnsma22]

Like Schurkey said, adjusting hydraulic lifters with the engine running is fool proof. To deal with the mess, I cut the tops out of an old pair of cheap valve covers to contain the mess.

[LPete]

These clip on the rocker arms and work really well to keep the oil contained:

http://www.jegs.com/i/Mr.%20Gasket/7...FQY-Igodtns_UQ

[johnsma22]

Originally Posted by LPete

These clip on the rocker arms and work really well to keep the oil contained:

They do keep the oil from flying out of the holes in the pushrods, but only for stock stamped rockers. To the best of my knowledge they won't work with roller rockers. They also won't keep the oil from running over the edge of the valve cover rails.

[ponjohn]

I too wondered what the technical description of zero lash.

Maybe do one cylinder with the engine running to get an idea of the pushrod resistance.

[Schurkey]

Originally Posted by ponjohn

I too wondered what the technical description of zero lash.

No lash = no free play--zero clearance between rocker arm and pushrod tip; zero clearance between pushrod tip and pushrod seat in the lifter.

Preload also has no lash--but--you've begun to compress the lifter's internal spring.

Originally Posted by ponjohn

Maybe do one cylinder with the engine running to get an idea of the pushrod resistance.

I hope you're not talking about resistance to spinning the pushrod with your fingers--'cause that changes with the surface finish on the pushrod, the oil on your fingers, and how strong your fingers are.

DON'T spin the pushrod to determine lash. I'd be rocking the rocker arm by hand--if it's loose, you still have clearance. As the clearance goes away, the rocker will become more "stable" and just at the point of zero lash the only way to move it will be to open the valve, (good luck!) or compress the spring in the lifter body.

Truth is, there's only two ways I set preload on hydraulic lifters (assuming an adjustable rocker system)
1. New engine--intake manifold OFF so I can SEE the preload on the lifters.
2. Engine running so I can HEAR the lash disappear.