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Old 07-02-2016, 03:37 PM   #1
Scooby Newbie
Member#: 36325
Join Date: May 2003
Location: Gainesville, Florida
Default Junkyard EZ36D with leaky exhaust valves

Has anyone else had this problem? The #3 and #5 valves leak. #3 has about 10% leakdown while #5 is closer to 90%. Judging by the excessive valve lash on those cylinders I'd say its carbon keeping the valves from closing all the way. I tried to clean #5 off as best I could with a brass tube cleaner and the lash did decrease by a few thousandths, but it still leaks.

I've never had carbon problems of this nature, probably because I never run factory PCV setups. Do you guys think I should pull the head and clean it, or will the carbon come off when its run? The motor only has 40k miles on it so I doubt there's anything mechanically wrong.

Otherwise it has great leakdown: 4-6% on the other cylinders.

Thanks for any help.
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Grant is offline   Reply With Quote
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Old 07-23-2016, 11:47 AM   #2
Scooby Newbie
Member#: 451235
Join Date: Jul 2016

i know it sucks, but the best way to positively remove all the carbon around the valves would be to pull the heads and remove the valves for cleaning.
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Old 07-24-2016, 02:33 PM   #3
Scooby Newbie
Member#: 180769
Join Date: May 2008
Chapter/Region: NESIC
lots of junkers


Run it and feed it some seafoam once it's warmed up. The point of poppet valves in combustion engines are that they are self cleaning. The tapered seat and the rotation of the valve crush and sweep carbon off the sealing surface.
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