What am I doing wrong?!?!?!?

[Fastbird93]

I CANNOT get my valves adjusted. NSA Pro Mag 1/6, 14011051 GM Guideplates, Comp R lifters.

I've tried zero lash, rockers were jumping off the valve stems (SA rockers at the time). I've tried 1/16, no dice. 1/8 turn, no dice. I just got done setting them to 1/4 turn past zero lash, and they're still making a hellacious clacking and snapping sound!!!!

I'm doing each cylinder at TDC by firing order. I've tried feeling for zero lash by the moving the pushrod up/down method, by the spinning method, and I've even gone as far as calling zero lash when the pushrod starts to get hard to spin instead of just starting to feel drag.

On cylinder number three for some reason when I spin the retaining nut down it doesn't resist as much with the rest of the set, but the lifters are NOT collapsed.


I can't really do a dynamic setting because of my OVC wires, as I'd be needing replacements real quick!

How quiet is a NSA/Guideplated setup supposed to be??

Anyone got any ideas???? This is driving me NUTS!!!!!

[Kevin - Blown 95 TA]

Did you replace lifters? Aftermarket ones bleed off sooner usually. Sometimes it helps to squirt oil into the holes or soak then overnight before putting them in the engine.

With the pushrods, you just want to take out the shake - spin can be deceptive since they might still be easy to spin past 0 lash, especially if the lifter bled down. Some of the lifters will bleed down more than others and give less feedback when they are at 0 lash. Don't want to overtighten them thinking you aren't at 0 lash when you are way past.

Also, are pushrods right length? if not then they can cause all kinds of problems. Check the pattern of the roller on the valve stem and make sure it stays the same across the top throughout it's range of motion (you might not get full range with bled down lifters and stiff springs).

Also make sure the underside of the rockers isn't hitting the retainer. Bad geometry, too big retainers, or overtightened rockers can cause this.

[Fastbird93]

Did you replace lifters? Aftermarket ones bleed off sooner usually. Sometimes it helps to squirt oil into the holes or soak then overnight before putting them in the engine.

With the pushrods, you just want to take out the shake - spin can be deceptive since they might still be easy to spin past 0 lash, especially if the lifter bled down. Some of the lifters will bleed down more than others and give less feedback when they are at 0 lash. Don't want to overtighten them thinking you aren't at 0 lash when you are way past.

Also, are pushrods right length? if not then they can cause all kinds of problems. Check the pattern of the roller on the valve stem and make sure it stays the same across the top throughout it's range of motion (you might not get full range with bled down lifters and stiff springs).

Also make sure the underside of the rockers isn't hitting the retainer. Bad geometry, too big retainers, or overtightened rockers can cause this.

I'm pretty sure the pushrod length is good, as the ONLY change from the previous motor was a move from 1.6 SA to 1.6 NSA rockers. Looking at it, this raised the stud ever so slightly since it's now sitting on a guideplate, but it can't make that much of a difference, can it??

The lifters are Comp R, and have less than 1K miles on them at the time of the motor replacement. I don't think I've got a collapsed one though.

I'm thinking of giving the running method a start tomorrow......about the only thing I can think of is they either need a good 1/2 turn (which comp doesn't seem to recommend) or the pushrods are too short, which would seem odd to me considering the heads were milled .010-.014 range, and the pushrods are stock length 7.200".

[Fastbird93]

Update:

Setup:
The Studs are ARP 7/16" studs.
Comp Pro Mag NSA 1.6 Rockers, 1305-16
Comp High Tech Chromemoly Hardened 7.200" Pushrods
GMPP 14011051 Guideplates
Custom One Off Joe Overton Cam

Geometry checks out fine, double checked yesterday with a pushrod length checker.

Some hindsight: On my initial attempts to set the lash, the car was cold, had not been warmed up or started for at least 24 hours. I would set each set of valves with each cylinder at Top Dead Center (TDC). I do know that they're going to be semi-loose as you rotate the crank around, but some showed to be loose to the point of 1/4-1/2 inch movement up and down, which doesn't seem right. Set the entire motor, start up, and get horrendous clacking. I ran it yesterday with a valve cover off, and you could actually visibly see 4 rockers on the driver side (only one without cover) moving up and down on the stud as the rocker was being actuated. I wasn't getting any oil squirting initially, but as the motor warmed up it started to squirt.

Yesterday, I tried to set the lash with the motor running. I didn't stand a chance. I just couldn't tell between all the clacking which rocker was making the noise. Gave up on that real quick.

Yesterday after the motor running attempt, I went through and did the GM Service technique of setting various Intake and Exhaust valves and then rotating the crank one turn and setting the others. Seemed like that was going along fine, and I set them to 1/8 turn. Started the car, and everything was too tight! The car would barely idle.

So, is it more advisable to try to set them with the motor warmed up or cold?? I know any of the three methods work, but am I missing anything???

[TraceZ]

I think I know what is wrong.

Depending on what stroke a cylinder is on, the valves will not always both be closed at TDC. You need to make sure the cylinder is at the top of it's compression stroke when setting the valves. If it is at the top of any other stroke, one valve will be open and you will not set lash correctly. That is why you had 1/4 to 1/2 inch gaps on some after you thought you had set them to 0.

What I'd do is use the starter to bump over the motor until you know both valves are closed by looking at the 2 pushrods. Then probe the spark plug hole with a plastic pen and turn the motor byhand until it is at TDC. Now you'll know for sure that both valves are closed and the cylinder is at TDC. You can now properly set lash on that cylinder to 0.

[Fastbird93]

I definitely KNOW I'm at the top of the compression stroke by watching the valves. I've been doing it cold, and comps recommendation is for doing it warm.

Trying again tonight.

[TraceZ]

I definitely KNOW I'm at the top of the compression stroke by watching the valves. I've been doing it cold, and comps recommendation is for doing it warm.

Trying again tonight.

I dont see any way there could be gaps as big as 1/2 inch after setting lash to 0 unless the cam was in the wrong position when you set them. It doent seem possible. I hope it works better for you tonight. I wish you the best. Let us know how it goes.

[Joe 1320]

Here's what I do, whether it is recommended or not is a different issue. I manually turn the motor with a breaker bar, setting each valve to the point of not being able to spin the pushrod between my fingers and I do this for at least several revolutions to make sure. I then move to the next valve and so on. It takes forever but I found this is a great starting place. I then start the engine and go through each valve again and take out any slack and add 1/4 turn past the point of silencing the rocker.

On engines with healthy lifters, cam, rockers and correct length pushrods, this has worked well for me for years.

[Fastbird93]

Yeah, I'm not at the point of being readily able to asjust them audibly with the motor running yet. This is the first time I've attempted to do these myself.

I may not get to them tonight, but I swear up and down that they WILL be set tomorrow, and I'll be posting good news about how my new motor feels being driven. I think I just need to take a day off and step back for a little while.