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GMTechBernard, Shop Foreman - GM World Class Tech
Category: Chevy
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Experience:  GM
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1995 chevy blazer: a 4.3L Vortec engine code W...adjustment

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I have a 1995 chevy blazer with a 4.3L Vortec engine code W. Is there rocker arm adjustment? The book I have says there isnt to just tighten them to 20 lb ft. But when I did that it looked like it had all the valves open. I got everything back together and now I have no compression in any of the cylinders.

Hello! Two styles of rocker studs were used on the 4.3L engine. Since teh "screw in" style with postive stop shoulders is most common, thats probably the reason why you got those instructions. However, some heads still used the older style "press in" studs, which require the manual adjustment.


  • Rotate engine until mark on torsional damper is aligned with "0" mark on timing tab fastened to crankcase front cover. To ensure engine is at No. 1 cylinder firing position, place fingers on No. 1 cylinder valves as the mark on damper approaches the "0" mark on timing tab. If valves are not moving, engine is in the No. 1 cylinder firing position. If valves are moving, engine is in the No. 4 cylinder firing position and should be rotated one revolution.
  • With engine in No. 1 cylinder firing position, adjust the following valves:
      • Exhaust valves 1, 5 and 6.
      • Intake valves 1, 2 and 3.

    Back off adjusting nut until lash is felt at pushrod, then tighten nut until all lash is removed. This can be determined by rotating pushrod while turning adjusting nut. When all lash is removed, tighten adjusting nut 1 and 3/4 turns to center lifter plunger.


    Crank engine one full revolution until mark on torsional damper and "0" mark on timing tab are again in alignment. This is the No. 4 cylinder firing position. With engine in this position, adjust the following valves:


    • Exhaust valves 2, 3 and 4.
    • Intake valves 4, 5 and 6.

    I listed all the cylinders to be adjusted, because I don't know what head you removed. You only need to adjust the valves that are on the head you replaced.

    Edited by GMTechBernard on 10/31/2009 at 5:41 PM EST
    Customer: replied 7 years ago.
    Thankyou. since I have tried to start it already with the rocker arms too tight could I have bent the pushrods or damaged the lifters?

    Unfortunately, that is possible. I would remove the rocker arms, pressurize the cylinders to see if the valves are sealing and to inspect the pushrods. The lifters are usually the last item to get damaged.


    If all checks out, go ahead with the adjustment procedure and see how it does.

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