1991 CHEVROLET LUMINA
291,868 MILES
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HELP, I have a 1991 Chevrolet Lumina with the 3.1 Liter V6. The timing chain broke on me. I brought some new replacement cylinder heads with new valves installed. My questions are.

1. I have install the timing chain with the timing marks on the camshaft & crankshaft sprockets at the 12 o’clock position with the number #1 piston at the top of the cylinder wall, is this correct?

2. Once I install the cylinder heads and torque them down, Could you tell me STEP-BY-STEP how to adjust the valves?

I don’t want any more bent valves once I get the engine put back together and start the engine up.

Thank You,
Bill Hewitt
Oct 26, 2012 at 2:19 PM
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the timing marks should face each other pic enclosed.

VALVE CLEARANCE ADJUSTMENT

NOTE: If valves and seats are reconditioned, adjustable rocker arm studs must be installed. Adjustment procedure is for adjustable rocker arm studs only. Engines
with original rocker arm studs are not adjustable.

1. Bring No. 1 cylinder to firing position and align timing marks on front cover and harmonic balancer. Adjust exhaust valves on cylinders No. 1, 2 and 3 by backing off adjusting nut until valve lash is felt at pushrod.
2. Tighten adjusting nut (while rotating pushrod) until all valve lash is eliminated. Tighten adjusting nut an additional 1 1/2 turns. Repeat adjustment on intake valves for cylinders No. 1, 5 and 6.
3. Turn engine one revolution to cylinder No. 4 firing position. Adjust exhaust valves on cylinders No. 4, 5 and 6. Adjust intake valves on cylinders No. 2, 3 and 4.

you sholdn't need the adjustable rocker studs, but if you can't get enough adjustment you' will, bu tyou shold be ok.
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Oct 26, 2012 at 2:25 PM