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  1. #1

    96 Challenger Exhaust Valves Carbon Buildup Not Equal

    I just cleaned the exhaust valves on the 96 Challenger I got last month. The front most cylinder had about 75% more carbon on the valve than the rear most valve. Also, the diaphragm on the rear most valve was not in place so it must not have been working to slide the valve up and down. I am wondering if all the extra buildup on the one cylinder means it is running too rich and if I should lean the carb for that cylinder a little bit? The spark plugs look a little oily on both sides and if anything the front most plug looks like it is running a little hotter than the rear plug (color inside is lighter.)
    Another thing I was wondering was if the prior owner didn't realize you can remove the front most valve if you remove it one part at a time unlike the rear one that comes off as a single assembly. Maybe he never cleaned the one in the front...
    Before and after photos. Does carbon like that effect performance?
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  2. #2
    Jeepster's Avatar
    Join Date
    Jul 2007
    Quebec, Canada
    For sure carbon like that affects the valve operation, plus if one of the diaphragm was not in wonder they don't have the same carbon on them if one may not be working properly.

    Prior to touch anything more, i would reassemble the cleaned RAVE valve, and run it like should only judge a combustion by the spark plugs not by a rave valve color. Run it with good functionning and clean RAVE valves first, then keep on eye on the spark plugs color...BTW i would put 2 brand new spark plugs also to have a good clean start....then you'll see the outcome.

  3. #3

    800 rave valves

    I would clean and properly ajust rave valves before messing with carbs.
    Also keep in mind that even when properly tuned, the rear cylinder runs hotter, which could expain less carbon build up. I would carefully inspect/rebuild fuel system and verify oil injection.

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