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ChadS
05-15-2004 10:33:05
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Re: Re: Re: setting valvles with a compression gau in reply to redcub, 05-14-2004 20:15:25
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Valve lash can, and does affect cyl pressure. too loose of gap, you lose all your camshaft specs, lift and duration is lost when they are too loose. Too tight, and the valves are held open and creates a leak, and eventually will burn the valve. I would say that the one low pressure cyl is not broke in all the way. new engines,,,, the more they run, the better they get, Breaking the engine in without a dyno, takes a bit longer than usual, the best way to break it in is to work the engine to establish a true seat in pattern in the rings. keep running it, it will pump up with the others in no time. Yes, this method will help all the cyls,, but you will fight it because the pressure is fluctuating so much due to break in, that you wont get an accurate reading at this time. Magic number for IH valve lash is .013to .014. on my 460, I took the old combine engine out, rebuilt the head, and put it together. It was famous for burning valves, so that was why we stopped using the combine, anyways,,, I was setting the valve lash at stock settings, and ran it, it was 135psi. It has 3-9/16 bore firecraters in it. it was also 64 hp or in that area, I eneded up at .012 on the exhaust, and .014 on the intakes, on this engine that is where it made peak cyl pressure, it is now at 155 to 160psi, just by a valve adjustment! I had to rejet the carb, and the timing to complimet the pressure increase, on pump gas 94 octane it is 73hp at 540. engine is a 263ci. Not bad at all for an engine that has not been rebuilt on the bottom end! ChadS
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