Discussion Forum - Northstar Chevelle Club

Some place I saw a spec for the rocker arm adjusting nut torque but can't find it now. I would find one that requires much more torque or buy new.

Well I am back from my CA fishing trip and ready to installed the nut and rocker arm to get the car up and running.  I threaded the nut on the rocker arm stud just to see how tight it goes on.  I think when it get the the installed position it feels more loose then when first threading on the top of the stud.  I am thinking maybe the stud also need to be replaced.  Is this a possible issue rather than the nut.  I have some almost new studs I could  replaced the stud with and then a new or reconditioned nut. 

I think I should also check the lash on the other nuts on cylinder 2,4,6, and 8.  Do I need to remove the nuts and push rods and start all over or can I just tighten the nuts until the push rods won't spin and then tighten the nuts one addition turn as it states in the service manual for 66?  The push rods spin now in the adjusting position for the valves to be adjusted along with the #2 exhaust.

-- Edited by jim larson on Sunday 23rd of June 2019 01:39:08 PM

Lost in the 60s wrote:

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Sounds like the stud replacement is a good idea. That non-running setting of the rockers is just a good starting point for an engine that has been disassembled. It still needs to be running to get them set properly, in my opinion.

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thanks for commenting Mitch.  Well I replaced the stud and the re-punched  rocker nut and tried to adjust the valves by tightening the nut until the push rod will not spin.  Then 3/4 of a turn.  Must have done something wrong, runs poorly.  I am not sure what I did wrong or how to identify which cylinder is missing. I think at least 2 cylinders are missing.  Maybe I didn't have the engine rotated to #6 firing position properly.  I had the engine warmed up, maybe I shouldn't have done that.

 

So I am back to square 1, how do I make sure I am at the number 6 firing position., If rockers on 6 don't move as I come up to TDC?  I am on the passenger side and don't want to use the number 1 firing position as a starting point.  I will then set the lash on the appropriate valves, by rotating pushrod until it doesn't spin and turn 1/2 move turn. Then rotate engine one full turn.  Is that right (book says 1 turn)? After adjusting the lash by this method, the methods say to lossen nut until year hear tappet noise an then adjust 1/4, then1/8 until the noise disappears.  But I guess my ears are not that good or I don't know what I am listening for.  So can I just go with the 1/2  turn after the push rod will not spin?   By spin do they mean easily spin or after working at it for a while I can turn the push rod?

-- Edited by jim larson on Monday 24th of June 2019 06:32:26 PM

I have always found it's too easy to over-tighten the valves with the "spin" method. I always have the engine running. Without oil pressure, some of the lifter pistons will allow the push rod to spin until it bottoms in the lifter bore and then the valve won't close once pressure pushes the piston up again. I have a special valve cover cut in half to contain the oil and there are clips to put on the rocker to keep the oil from spraying out the push rod hole.

The part of your "method" you refer to above as turning out until a tapping sound and then tighten, is running. Once I have loosened until one clicks, I turn down slowly until it just stops and then continue 3/4 turn to center the piston in the lifter bore. Aftermarket lifters could require a different amount of preload...

Center mounting stud, small block cover. I have a big block cover here. We can find a day that you aren't fishing.... and run it up and go thru this with you.