HELP, I have a 1991 Chevrolet Lumina with the 3

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1991 CHEVROLET LUMINA
291,868 MILES

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

1 Reply

HMAC300

MECHANIC
48,601 POSTS

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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