devilfish

I follow this system for Adjust Lifter Preload/lash.
https://www.corvetteforum.com/techti...=142&TopicID=5

BUT I think some of my hyd lifters is bottom out?
On some rockers I can turn 1 full turn after zero lash without trouble, and thats fine
On some others just 1/4 turn before I start to press down the valve. ?!
That must mean that those lifters is fully depressed when I set zero lash? Or does that mean the lifters are harder to compress then the vavle springs?
Thanks

CFI-EFI

What is means, is that you missed the zero lash point, and tightened them beyond zero lash. Rather than twist the push rods between my fingers, I prefer to jiggle them up and down to accurately locate zero lash. Try again.

RACE ON!!!

devilfish

Will give it a try thanks.

I heard about collapsed lifters, that could not be the case here also?

1987vette

I just when thru adjusting mine and the nuts holding rocker down should be all down about the same amount - if you had a collapsed lifter I would guess that the nut would be a noticible difference

JAKE

I agree, you got crossed up somewhere and tried making an adjustment when the lifter WAS NOT on the base circle of the camshaft lobe.

I've said this many times before, insuring that the lifter is on the base circle of the lobe is the most important step.

Whether you choose 1/8, 1/4, /1/2, 3/4 or 1 full turn of preload is a personal preference call (I prefer 1/2) but no matter which one you choose, the lifter HAS to be on the base circle.

Don't go off the deep end and start thinking things like collasped lifter, etc. Just return to square one, TAKE YOUR TIME, and make sure you've properly identified which is intake and which is exhaust.

After you've correctly done this a few times it'll become second nature, like riding a bicycle. Remember how "hard" it was the first time you got on one? What about now?

Jake

conv90

Jake, is it true that if you are at TDC (stroke event) on # cyl you can be sure to have the INTAKE valves closed (lifter in the base circle) on
1-2-5-7
and EXHAUST valves closed (lifter in the base circle) on 1-3-4-8

Then, when a full turn of the engine is made (at TDC on cyl #6)

you can be sure to have the INTAKE valves closed (lifter in the base circle) on
3-4-6-8
and EXHAUST valves closed (lifter in the base circle) on 2-5-6-7.

This is true only with cams with stock or NOT overlap or on all Chevy engines with all cams?
-Beppe-

CFI-EFI

I don't think that is the cause of the problem, here. When the final, 1/2 or 1 turn of preload was being taken up, and the valve started to open, that is the proof that the starting point for the adjustment, was well beyond "zero lash".

Yes! It IS the problem, here. You collapsed the lifters by going past the zero lash point, before you started to adjust the preload. Don't panic. It's very unlikely that you've done any damage. Just back off on the adjustment and start over.

RACE ON!!!

JAKE

Think about it this way.

Let's look at the BIG picture here.

You've got a person who is unfamilar with adjusting the preload on hydraulic lifters. Yet, it's expected that he'd be able to correctly identify the intake and exhaust rockers sixteen (16) times on two different sides of the engine without making a mistake.

That's a receipe for a mistake to happen. Remember, it only takes one (1) to be set incorrectly for the engine to run badly. That's why I don't recommend using the procedure you find in some of the service/shop manuals. It's just too confusing for the uninitiated and too prone to causing an error.

K.I.S.S. Start at the front and work your way back to the rear one is by far the simplest way to tackle the chore. After one side's done, go over to the other side of the engine and, again, start at the front and work your way back. Doing it that way, all you'll have to remember is EIIEEIIE.

That's the way it's recommended in the cam catalogs and, in addition, that's how you set valve lash with a mechanical cam. Ever tried setting valve lash on a mechanical cam with the engine running? LOL

The procedures in the manuals is written with the mechanic in mind who knows his/her around an engine. Sure. if he knew what he was doing he could use that procedure and set all 16 much quicker, but if he knew what he was doing he wouldn't be posting here, right? No offense intended.

Jake

CFI-EFI

And even easier than remembering Ee Ii Ee Ii Oh (from Farmer in the Dell?), all one has to do, is to see if the valve in question lines up with an intake or exhaust, manifold runner. Duck soup.

RACE ON!!!