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350 Rebuild idle problem


Gareet
12-09-2003, 11:53 PM
I just got my 1994 z-71 back together. I did the trans and the engine. The problem I am having is that once we got it back together we realized that we had the valves to tight because we had no compression. So after backing the valve adjustment down about 3/4 of a turn it fired right up. But the engine will only stay running if I have my foot on the gas. We have good vaccuum, and spark. It runs strong when I keep my foot on the gas a little. We timed it with the ETS disconnected then plugged it back in. We played with the timeing some and weren't able to get it to idle on its own. Any help would be greatly appreciated

Stock pistons
Stock intake
Stock heads
Lunati 00016LK cam. 1500-5200 rpm range
Stock computer
Stock exhaust manifolds.

I'm not sure if the valves are to loose. we had 150psi compression on all 8 cylinders. I didn't hear any lifter pinging. and the rocker arms weren't clattering. Also the check engine light does not come on. So i'm confident all my sensors are working.

GMMerlin
12-10-2003, 09:17 AM
I would check the valve lash first and make sure it is adjusted properly.
thighten the rocker nuts til all lash is removed then turn nut 1 full turn

With the engine at #1 tdc, adjust intake 1257 and exhaust 1348
turn engine to #6 tdc, adjust intake 3468 and exhaust 2567

This should take care of the valve problem

Gareet
12-10-2003, 12:39 PM
When we had the motor out of the truck on the stand we tightened the valves this way.
I tightened the nut until I couldn't turn the pushrod with my fingers, then went 3/4 of a turn. That gave us the problem of the valves being open all the time "to tight". so we losened them all up while it was in the truck, and went back through and tightened them till the pushrod started to "drag".
I could still move then pushrod but there was some friction on it. Then I went a half turn more when I reached that point. One thing I should note is that when we had the motor on the stand there was no oil pressure. Now that we have had it running and had oil all the way to the top of the motor I'm wondering if that will change how we have to adjust those things.

I gotta ask this to. As far as the "lash" your talking about is that up and down movement of the pushrod, turning the pushrod, or if the rocker arms move side to side?

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