Adjusting Valves: Engine On or Off?

Discussion in 'General Ranchero Help' started by colnago, Mar 14, 2019.

  1. colnago

    colnago In Fourth Gear

    Messages:
    412
    Location:
    Ridgecrest, CA
    I was just wondering everyone's favorite way of adjusting the valves on their 260/289/302/351 engines. Engine running, loosen 'til it clatters, tighten 'til it stops? Engine off, spin the pushrod while tightening the rocker 'til you can't spin the pushrod, then add 1/2 - full turn? Other? I have some minor clattering, so I will try to adjust the valves this weekend. The engine is in the car, if that matters.

    Joseph
     
  2. TestDummy

    TestDummy In Maximum Overdrive SILVER MEMBER

    Messages:
    22,189
    Location:
    C'Ville
    I've done the spin the push rod method, which is a lot less messy. My old machinist, Phil Wilson, a legend in Michigan, taught me that, so why would I deviate. Do it with warmed up engine, for sure. He said to warm it up, do one side. Warm it up again and do the other.
     
  3. colnago

    colnago In Fourth Gear

    Messages:
    412
    Location:
    Ridgecrest, CA
    How much more do you tighten the nut after you can't spin the push rod?

    Joseph
     
  4. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    571
    Location:
    Palm Coast, FL
    Actually, you are looking for "zero lash" which means no gap between the pushrod and rocker arm. So once the pushrods get some resistance (spin them while you tighten) go 3/4 turn more with a stock engine. I just did my 289 valve lash and the instructions with my Edelbrock cam told me not to pre soak the lifters in oil, then adjust to zero lash and add 1/4 turn.

    If you tighten them until you can no longer spin the pushrod you run the risk of over tightening the rocker arms which may prevent the valves from ever completely closing.

    I have tried the engine running method.. it was a mess. Ill never do that again. LOL.
     
    Last edited: Mar 14, 2019
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  5. Dyno

    Dyno In Third Gear

    Messages:
    175
    Location:
    Croydon, Pa
    engine off this can be done in car or on engine stand . Intake opens and just starts to shut adjust that cylinders exhaust. Exhaust just starts to open adjust intake. Just get the lash out ( no movement rocker) then give half turn tighter.
    Will feel drag if trying to turn push rod, but can still over tighten if lifter is collapsing. If you can see lifter top look for .04-.06 plunger depress below lock ring.
    Oh this is for hydraulics not solids.
    Agree engine running a mess ! Did it that way before I learned better.
     
  6. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Messages:
    8,472
    Location:
    Everett, WA
    The only time it wasn't a mess is when I used the little spring clips on the backside of the rockers (on a Chebby SB), and the drain holes were completely clean. Having said that, it still got oil on the exhaust, causing copious amounts of smoke.
     
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