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wishbone

Dang! Did something wrong when checking compression...

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Howdy,

I recently bought a '39 LZ and was messing around this weekend trying to get it running for the first time in many years. I removed the spark plugs and sprayed some Sea Foam into the tops of the cylinders to let them soak for a few days before turning the engine over by hand. Then comes the weekend and I decide to give her a go...nothing. She's got spark and I'm feeding fuel to the carb via coffee can and gravity. Compression test is always early on my list of things. So then after 6 uneventful (but good) compression readings on the 7th I guess I must have screwed the tester too far in because the valve came up and hit the bottom of the tester. I heard it and felt it.....then of course, zero compression on that cylinder.

With a flashlight it looks like the valve is going up and down, but not as snappy or evenly as the others. What do you think I broke? The valve? I then went on to test the other cylinders on that side (very carefully) and got decent readings.

I know that I have to tear it down and do the necessary repairs, but thought I would ask around before hand to get some advice. This will be the first V-anything that I have worked on. Most of my amateur experience is with Hudsons.

Any advice and source for parts and tools would be Very helpful.

thanks, E

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By removing the intake you can check the springs and valve stems. That is easier the removing the head and you are going to have to remove the intake any way. Lee

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The spark plug holes are off center from the exhaust valves and I suspect the valve may have got bent when it contacted the tip of the tester. The valves can get real "sticky" on these 12's if they sit dormant for long periods of time so that might also explain the uneven action if the valve hadn't hit the tester.

If you can't get any compression you'll have to remove the head for a look-see. The intake manifold will have to be removed to get at the valve guide and keeper if the valve has to be replaced.

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Sounds like I have to do the deed and look in there. I talked with Merv Adkins today and he agreed. He also said that he might have some new and/or used valves if I need 'em.

thanks for your responses, Erik

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