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Bad valve

699 views 3 replies 4 participants last post by  steve t 
#1 ·
My 350 chevy started running rough after a burn out. Held a dollar bill up to exhaust and it sucked it in. Does this sound like a bad valve?
 
#3 ·
Doc here , :pimp:

Could be anything from a miss fire to a blown piston depending on how server it is..

Get a Vacuum gauge and Compression tester and do the BASICS first..run a vacuum test, manifold source, it should read between 17 and 21 lbs, Steady needle..flucutions in unison with a miss indicate Leakey valves / burned valves / seals..

Do a compression Test and leak-down, low numbers indicate the bad cylinder, norm is within 125 to 150 PSI..

Look at the plugs, are the oil/Gas Fouled? this is another indicator..

Causes could be anything from a fouled plug to a bad / mis adjusted rocker or bent push rod .. to Bad valves..only testing will tell you.

Doc :pimp:
 
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