Lew Palmer wrote:
>
> OK, folks. I have another mystery.
>
>
>
> I've been finishing the restoration on a J2 for a fellow club member.
> Unfortunately, I did not assemble the engine, and the person that did
> apparently had no clue on how valves are adjusted on triple-M engines.
> Therefore, when the head was assembled, there was insufficient (read NO)
> clearance on the intake valve on #4 cylinder and precious little on the
> exhaust valve. A compression test showed around 95 pounds on each of
> cylinders 1, 2, and 3, and zero on #4.
>
>
>
> Hoping to discover it was only the tight valves causing the problem, I
> then removed the cam shaft so that all valves should have been closed.
> To my surprise, #4 cylinder now showed about 45 pounds. To my further
> surprise, #1, 2, and 3 now read between 45 to 50 pounds.
>
>
>
> What would cause a normally operating cylinder (with valves opening and
> closing properly) to show 95 pounds pressure and that same cylinder to
> show 45 pounds with both valves closed?
>
>
>
> Please help clear up the fog from my brain and give me a hint of what
> I'm missing.
>
>
>
> Regards,
>
> Lew Palmer
>
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