adjusting rocker arms on 3.4L V6

I recently replaced the head gaskets on my 97 Chevy Venture (3.4L V6). When I put the rocker arms back on, I torqued them down per the instructions in my Haynes manual. At the time I was concerned because
some of the rocker arms seemed looser than others. When I started the van, I could hear a clacking sound. My uncle tells me I need to find out how to do a "valve lash" adjustment. What steps should I take when installing the rocker arms in this engine?
Thanks, -Stephen Smith
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until it starts to clatter (this is zero lash). Then SLOWLY tighten down 1/4 turn at a time until you have gone 1-turn. Do this on each valve.
To do it without the engine running, position the engine to fire #1 cylinder and back off the adjustment until the pushrod rotates freely. SLOWLY tighten the nut until resistance is felt (ths is zero lash) then SLOWLY tighten the nut 1-turn farther. Do this to exhaust on cyl. 1, 5, 6 and intake on cyl. 1, 2, 3. Then rotate engine into position to fire #4 cylinder and do exhaust on cyl. 2, 3, 4 and intake on cyl. 4, 5, 6.
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"Stephen" wrote

There is no "valve lash" adjustment on these engines. One of two things has happened. Perhaps 3 things. One, you mixed up the short and long pushrods (short pushrods go on the intake valves, long on the exhaust valves). If you did do this...and you run the engine for any length of time, you can do some major damage to the engine.
Two, you didn't get the rocker arm pedestal down into the cylinder head properly (both the head and rocker arm pedestal are notched, cylinder head is the female side, pedestal is the male side) and so even though you have the rocker arm torqued down, it's not actually all the way down.
Three, sometimes, it's completely normal for the lifters to either pump right up and when you start the vehicle, it seems as though there is no compression, or they "won't" pump up right away, and you end up with lifter noise until the engine warms up a bit. This is usually due to the coolant that has been running around in the engine oil. Dexcool makes a scummy brown sticky coating that gets all over the inside of the engine and the internal parts of the engine.
Hopefully for you, it's either 2 or 3.
Ian
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