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Need help with 1967 L-79

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  • Joe #39538

    Need help with 1967 L-79

    My 67 327/350 runs smoothly but is very under powered. Yesterday I did a compression test.

    I ran the engine for about 5 minutes then pulled the plugs. The plugs have less than 1000 miles on them. All had blackened electrode ceramics, and the plugs were wet with what appears to be oil on them.

    I held the carb open while doing the test. The compression test revealed six cylinders with a compression of 150. Cylinder #6 was 140 and cylinder #8 was 110. When I tuned the car up last spring, plug #8 was fowled.

    Today we put oil in cylinder #8 and re-did the compression test and it was still at 110. This seems to indicate that the rings are not the culprit?

    Also today, we pulled the valve covers and found the left head to appear normal with the inside of the valve cover clean end your typical oil in the low spots on the head.

    The right side was another story: There is water (coolant?) pooling in the lower left part of the head above #8. There are also drops of water (coolant?) on the last four lifters above #8 & #6. Inside the valve cover are whitish deposits which look like mayonnaise at the end of the cover over #8. A pressure test of the coolant system doesn't show any leakage. The oil on the dipstick looks normal though about 1 quart down since last year. (It has about 1000 miles on it).

    The left head is #3890462 H166 and the right head is 3890462 H176.

    The fellow that was lending me his leak down tester has not come through so I am still waiting to do the leak down test.

    My question is what is that liquid and why is it there? I thought that it could be condensation, but only on one side and only over the poorly performing cylinder?

    Any ideas out there?
  • Clem Z.
    Expired
    • January 1, 2006
    • 9427

    #2
    Re: Need help with 1967 L-79

    water could be coming up a head bolt hole from a blow or leaking head gasket.

    Comment

    • Jim T.
      Expired
      • March 1, 1993
      • 5351

      #3
      Re: Need help with 1967 L-79

      Joe your 67 L79 not running well and all spark plugs coated black could be attributed to the carburator over rich problem. Having a Holley, on my L79 I know how easy a little back fire can ruin the power valve. A quick test can usually pinpoint a bad power valve which will enrich the the fuel mixture when it is not needed. At the front of your Holley primary air inlet is a vertical tube. This is the vent for the front fuel bowl. Start your L79 and remove the air cleaner. With the choke off and at normal idle speed put a finger over the vent tube for the front fuel bowl. If the engine dies right away this verifys that the power valve is not holding vacuum and needs replacement. If the power valve is good the engine will also die, but it takes a longer time.

      Comment

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