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Discussion Starter · #1 ·
I had been adjusting the valve lash on a 350ci Chevy bored .60 over. When you turned the harmonic balancer, you could hear air releasing. Now it seems as though there is no more hissing from air release and nothing pops your finger off number one plug. Is this loss of compression and if so what would have caused it? I'm hoping it's a minor adjustment of some sort. Any help is appreciated. If you need more details please ask and I will try to answer. While adjusting the valves, I was TDC on #1 and tightened bolt till pushrod just barely turned...tightened a half turn. And then did the ones it calls for in the nova book to do while TDC on #1. Then rotated harmonic balancer around to TDC again and adjusted the other intake/exhaust the booke called for tightening the same way. HELP
 

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I take it you are running a hyd camshaft? Are you turning the engine over by hand using the balancer? If ithas plugs in it you should have quite a bit of resistance from compression. Are you sure youwere at TDC on the comprssion stroke? If you were at TDC on the exhaust that would throw the pattern you used off.
 

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Discussion Starter · #3 ·
I hope I'm running hydraulic cam.....the engine was built before I bought it and not sure what's in it as far as cam. I turned the engine over by hand using the harmonic balancer. I was checking for compression in number one as i rotated the balancer and that's when i noticed no matter which time the mark came around....no air came out. You could hear air releasing when you did it before...that don't even happen anymore. There was some resistance while turning the balancer.....but not a whole lot. I checked tonight and I have compression coming from #3 and #7....but no other plug holes.
 

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Sounds like the valve adjustment is wrong and the valves are being held open. I'd recommend doing it again. Take the rockers loose on number one and put your finger on the pushrod for the intake valve. Rotate the engine untill you feel the pushrod move up then completely down. Use a small wooden dowl and place it in the spark plug hole and SLOWLY rotate the engine untill you feel the piston hit top dead center (stops moving up), then adjust your valves. This will make sure your on the compression stroke.Also, the pushrods will still turn freely even though your tightening the rocker enough to collapse the lifter. When your adjusting the valves, you need to tighten the rocker nut untill the pushrod dosen't move up and down anymore, then add 1/2 turn. Your lifters are collapsed and holding your valves open causing the loss of compression. If you try to start the engine now and it fires you could damage your lifters, bend your pushrods, etc., so readjust your valves before trying to start it.
 

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ya it does sound like you gave it too much preload and now the valves are being held off the seats. In the Nova book, if we are talking about the same book, it also mentions you can use a .0015(I think that is the thickness) feeler guage to help you determine when you are at zero lash with the valve. Just tighten the rocker adjustment nut until you feel a slight drag on the feeler guage then set your preload on your lifter.

good luck. ;)
 

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Discussion Starter · #7 ·
It must have been the valves not adjust right. I loosened them all up and started over. Compression is back and sounding good. I hate doing things while bs'n with people. You tend to forget what you were doing. But ya get thru it. Thanks guys....
 
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