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Any tips on setting valve lash?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 8_YOUR_H2, Jan 21, 2001.

  1. 8_YOUR_H2

    8_YOUR_H2 1/2 ton status

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    Hayes manual says to tighten the rocker bolt and eliminate pushrod lash then tighten 1/2 - 1 1/2 turns. This is kind of vague! I just tighten the bolt untill the pushrod doesnt have any more up and down movement then tighten another half turn, the pushrods dont have any movement nor do they spin around they are not moving at all. Does this sound right to you? BTW it is my 350 with hydraulic lifters
     
  2. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    mouse, one and a half turns is about a turn to much. when you put the pushrod in the proper place and with the valve closed, (for each particular cylinder).tighten down the nut on the rocker arm, while spinning the pushrod with your thumb and forefinger. tighten until the pushrod does not turn any more with your fingers, then go 1/2 turn to 3/4 of a turn. rotate the engine to get the other valves closed so you can adjust them properly........ another way is to run the engine and tighten the valves until they stop clanking or making noise then go 1/2 turn to 3/4 of a turn. by the way if you over tighten the nut on the rocker you can strip the lobe off the cam, so be careful....js
     
  3. Mr Red

    Mr Red 1/2 ton status

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    I found Chilton to be more accurate than Haynes. I used the procedure from AllData that's on a Popular Mechanics CDROM for my '86 305.

    Since you've got hydraulic lifters, I wouldn't worry about it unless you've removed the head, replaced lifters etc. My Chilton book for 1988-1998 says none of the engines need to have lash adjusted because they have hyrdaulic lifters.

    I'd leave 'em alone unless you have to do it. As the other post says, you could screw things up pretty good if you're not careful about overtightening or doing the wrong valve, in the wrong position.

    [​IMG]
    <font color=red>David, '86 & '91 K5</font color=red>
     
  4. Wheels

    Wheels 1/2 ton status

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    I found that the best way to adjust the lifters is to rotate the engine to get the opposing valve on that cylinder to be at full open. Adjust the valve (one that is closed on that cylinder) to .015" with a feeler gauge. Then turn the adjusting nut a full half turn to seat it. Then do this for each valve in each cylinder. This was the procedure that the CompCams tech line recommended, it is long and tedious but it works. The rotate the engine until the intake valve on cylinder X is open the adjust the valves on cylinder Y method always left mine chattering
     

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