OK. I had the motor out of my 85 camaro because of a rusted through oil pan.

I changed the timing chain and oil pump and went with a set of reconditioned heads.

I put everything back together and here is the dilemma.

I followed the GM service manual on how to adjust the valves. Something like when #1 is in firing position you can set ### on one side etc. But the book said to spin the pushrod in my my fingers and tighten until it spins no more and then tighten an additional 1.5 turns.

Set all the valves that way. I spun the motor over with the fuel pump disconnected and the spark plugs out until I saw oil come out of the pushrods so I know the motor was primed.

I did a compression test and got ZERO compression for all cylinders!!!!

I loosened the rocker nuts back until I could spin the pushrods freely in my fingers with a little drag. No the compression jumped to about 140 psi per cylinder. This motor has about 165,000 miles on it so I know the rings are letting a little compression go by.

But the pushrods are loose to the touch. Will this "chatter waiting to happen" go away when the motor fires up? Are the lifters shot?

I checked chiltons manual and they recommended starting the motor with splash clips in place and setting the rockers that way....um, you can get the valve covers off with the intake in place. So are you supposed to remove the valve covers, reinstall the intake, start the car, set the valves, remove the intake, reinstall the valve covers and then reinstall the intake? That sounds kind of dumb, but this is GM.

 

umm, you CAN take the valve covers on and off with the intake on there....


anyhoo, thats how ive always done it....... except i didnt use thoes lil clips... i just used a cut valve cover..

 

recondition heads mean that they were milled, and you will need shorter pushrods.

Luckily undersized and oversized pushrods are common and cheap.

 

yeah but they usually take a couple of thousandths off the heads to clean them up.

Pushrods come in sizes of +0.100, +0.200

a couple of thousandths will not make much of a difference I wouldn't think

 

NONONONONO, NOT "Until the pushrod spins no more" BAD BAD BAD

You're *WAY* beyond zero lash if that's what you did. If you fire it up like this you'll wipe the cam. Back 'em off till they're free, tighten till you cannot wiggle the pushrod up and down AND feel 'drag' on the pushrod when spinning it from the pressure between the lifter and pushrod, turn additional full turn. Fire up motor, back each one off till it ticks, tighten until the ticking stops, then tighten additional 1/4 to 1/2 turn.

I don't know how you guys are finding these manuals with "How to destroy your cam" sections.. but yeek.

 

This is one of the things I like about the 3800 I'm swapping in, seat pushrods, torque to ___, turn an additional 90* & your done. I have never had to mess w/lossing/tightening rockers, & am blessed w/that . Karl's gonna come in w/his use air pressure to method.

 

The book is not allways the best source. The best and easiest way is to just set the valves close and then do the final adjustments with the engine running. A solid lifter motor can be done straight and simple but on a hydrolic system, it much easier to adjust them in with the motor running.

Matt

 

So far in my career, I have only dealt with solid roller cams...I never knew how hard hydraulics were to deal with.

Does anyone know how to get the valve covers off with the intake plenum still attached? there is so much crap to deal with.

 

Oh BTW, the book about how to wipe out a cam was the original GM Service Manual for 1985 Camaros that a dealership would have. Its about 1000 pages and the size of a large phone book.

 

It much easier if you hack a big hole/slot in a set of spare covers. Other wise it gets to be an oily mess.

more good news hugh??

Matt

 

Thanks for the idea, Gumby.. I think I'll do that whenever I get off my lazy butt to reset all of mine.. though I look forward to the rollers in my '88 far more than the flat hydros in the 86... fortunately both run so I won't be bothering with any initial settings...

 

For setting my valves on the 3.4 in the Firebird, I used the compression gauge method. It worked prefectly.
When I used the compression gauge method in the 3.4 in the Blazer I was met with valve train clatter. Why not?
Go tighten in quarter turns, keep reading compression. That's what's I'm gonna be doing in my Blazer soon.
Pre-load is the word.
140psi on a 165K motor is acceptable.

 

I think you better explain it more.
Do you just keep adjusting the valves until you get good psi??? What if you had a leaky ring?

Matt

 

I crank engine until I get highest cylinder compression reading.
Usually got 150 PSI on the Blazer 3.4. This engine I need readjust the valves. I will bump start to each cylinder position and feel push rod rotation from there. I hope it's only necessary to go 1/4-1/2 turn, each cylinder.
The Firebird. I had MAJOR trouble adjusting valves.
Finally did it by compression guage (registering 175/200 PSI each cylinder). When I registered highest compression, I was done adjusting valve.
Went back thru valve drivetrain to check all readings & checked again, then buttoned up valve covers, Firebird never touched since.
I do the "by feel pushrod" adjustment method on my Chevy 350, any day. For some reason, those V8's are easier to do.