Nate's Z28 Project

[Fox Slaughter]

Gotta love the smell of a new engine.

[mcalus]

Yeah thats your knock sensor, should be on the passenger side. (about the same place)

[TylerT/AZ28]

why a full turn? that seems excessive.

[nascarnate326]

why a full turn? that seems excessive.

Thats what corvette forum said to do. Hard to find real specs vs someone's opinion.

[Fox Slaughter]

Read Shbox. Its suppose to be a 1/4 turn pass zero lash.

I found it easiest to do it while having the engine idling.
Have them tight so they don't click.
Loosen one until it clicks, tighten till it stops then 1/4 turn more.

[nascarnate326]

And other pages say one and a half turns- hot cam kit specific.

Are they different for the stock 1.5 vs these 1.6?

[Fox Slaughter]

To me zero lash is zero lash. All zero lash is, the point where there is no slack between the lifter, pushrod, rocker arm, valve stem. So the point at which the clicking stops is "zero lash" or you feel drag on the pushrod. Turning it a 1/4 turn is just to "lock it". To me going farther you are now putting it past zero lash and now will cause the valve to not seat fully, keeping it open. Which will lead to loss power and burning the valve.

Different valvetrains will take different amount of turns to get to zero lash, but zero lash is zero lash.

[birdie2000]

The turn past zero lash is to preload the hydraulic lifter. There is actually a preload spec for the lifter. For instance, for LS7 lifters (stock replacement for LT1 engines now) the spec is .060"-.100" with most people saying to aim for .080".

[Fox Slaughter]

The problem I see with preloading the lifter is that if they are brand new lifters it might work because they aren't pumped full yet, if you do it while running the lifter is pumped up so if you tighten them past zero lash you are now putting even more load on an already pumped lifter.

http://www.google.com/url?sa=t&rct=j...43828540,d.dmg

Crane Cams says to do the push rod spinning method, then a 1/2 turn.

[birdie2000]

You're supposed to let them soak submerged in oil overnight to reduce that. That 1/2 turn is adding preload to the lifter. Hydraulic lifters are intended to have a little preload.

That said, after setting the lash on a solid roller cam I don't think I'll ever go back to hydraulic. So much more straightforward.

[Fox Slaughter]

With that old school tool known as a feeler gauge?

[nascarnate326]

Guess I can back them off a half turn and if they are making noise tighten them up.

[Fox Slaughter]

Thats why I would do, but I tried setting mine with the engine off and I didn't like it when I started it. So I ended up doing the engine running method which I think is much better. Just lay a towel across the exhaust to catch oil and go to town, it literally takes like 10 seconds to do each one.

Clicking is a lot easier then telling, is that some drag or not?

[TylerT/AZ28]

i make sure they are tight and barely able to be spun with fingers while the engine isnt running so they dont get thrown out or whatever, once idling loosen them till its starts to click so much it sounds sdangerous then tighten till it stops then give your rest 1/2, 1/4 whatever else turn. your engine will fluctuate a bit while doing it, or at least my truck did and you can sorta tell by listening if the engine likes a quarter or a half or 3/4 of a turn.

[nascarnate326]

Ill check the pushrods to see if they spin. If I can get the motor mounts, power steering, and alternator done today that should finish up the motor.