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99 350 valve lash,,,, please help!

Discussion in 'Chevy C/K Truck Forum' started by nussford, Nov 28, 2011.

  1. nussford

    nussford New Member

    I got a 99 350 that I got hot, cracked heads. So Im on way bak together now but I was. doing the valve lash and noticed something odd. I did them all once rolled the engine back to tdc and the push rods was a little loose again, so I adjusted them again and, rolled it over to next set of valves and again loose. So adjusted them again and back to tdc and they was loose again, did this about 5 times until they stopped loosening up.does this sound right or what should I do.
  2. pilotj

    pilotj New Member

    Did you adjust them this way?
    With the engine in the number 1 firing position, adjust the exhaust valves for cylinders number 1, 3, 4, and 8 and the intake valves for cylinders number 1, 2, 5, and 7.
    Turn the valve rocker arm nut counter clockwise until the valve lash is felt in the valve pushrod.
    Turn the valve rocker arm nut clockwise until all the valve lash is removed. Zero valve lash can be felt by moving the valve pushrod up and down between your thumb and forefinger until there is no more up and down movement of the valve push rod.
    When all the valve lash is removed, then turn the valve rocker arm nut clockwise 3/4 of a turn.
    Turn the crankshaft clockwise 1 revolution until the alignment mark on the crankshaft balancer is aligned with the notch in the engine front cover tab.
    With the engine in the number 6 firing position, adjust the exhaust valves for cylinders number 2, 5, 6, and 7 and the intake valves for cylinders number 3, 4, 6, and 8.
    Turn the valve rocker arm nut counter clockwise until the valve lash is felt in the valve pushrod.
    Turn the valve rocker arm nut clockwise until all the valve lash is removed. Zero valve lash can be felt by moving the valve pushrod up and down between your thumb and forefinger until there is no more up and down movement of the valve push rod.
    When all the valve lash is removed, then turn the valve rocker arm nut clockwise 3/4 of a turn.

    I've always adjusted mine with the engine running. It makes a mess, but works better for me. Just get you lash close then fire it up.

    Start the engine and allow it to warm up. Begin to loosen one of the rocker arm adjusting nuts. You should hear the valvetrain just start to "clatter". Slowing tighten it down until the "clatter" just stops and then turn it 1/4 - 1/2 turn additional to set the plunger depth (lifter preload). Continue this procedure on all the valves. If you hear excessive noises or the vehicle runs rough you will be doing the procedure again. As stated above, if you have access to a mechanic's stethoscope, you can set the end at the top of the rocker stud to listen to the noise a loose adjustment makes, which will make finding "zero" lash easier.
    Just make sure youdon't have the lash to tight before you start it. Too tight can damage the cam/lifters or bend a pushrod
  3. nussford

    nussford New Member

    Yes I did adjust them like that, but when I came back around to #1 fire pos. They was alittle loose again so it took about 5 time to get them with no movement in the pushrod.couldn't turn with my fingers easily. So should I back them off a turn or so and try to start it and adjust them running. And no I don't have a scope. It is completely back together and I tried to start it and it hit almost instantly but no start, and wouldn't hit again until it set for a little bit.
  4. pilotj

    pilotj New Member

    Yep, back them all back off until loose and readjust. It shouldnt be so tight as to not be able to spin the push rods. Thats way to tight (compressing the hydraulic lifter). All you want to do is eliminate the up/down slack of the push rod, then 1/4 turn more. Get them all set like that, then fire it up to see if any are clacking and adjust again while running.
  5. nussford

    nussford New Member

    Alright ill try in the morning sometime,keep a eye on my thread so I can keep you helping me, I really appreciate the help.
  6. pilotj

    pilotj New Member

    Nussford, I'll be leaving town tonight. Won't be online again until tomorrow night. Feel free to text me though at any time. I'll send you the number in a private message

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