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Subject:<No subject>
From:John Rodgers
Date:Fri, 12 Nov 2004 18:56:54 -0600

Don Williams wrote:

> I did an overhaul this past summer on an 84 1.9 waterboxer engine. It
> seems
> to run like a charm but is gutless.

I had an aircraft engine rebuilt once.  Everything was good,
compression, ran good, etc. Problem was, in spite of the engine running
smooth like a champ, it  was gutless. Would barely produce enough power
to even get off the ground, much less fly away anywhere. This engine did
not have hydraulic lifters, but solid lifters, so I had the mechanic
perform what was know as a "Hot Valve Timing Check." That is with the
engine being in a cold state, the engine valve clearances were set as if
the engine were hot. The valve cleearance specifications for this were
provided by the engine manufacturer. Once that was done, the timing and
the valve opening and closing was checked using a degree marked device
mounted on the crankshaft. Turned out the valve timing was wrong, and
therefore the cam timing was out one or more teeth. . The intake valve
was opening late, and the exhaust valve was closing early. The
significance of this is that the fuel air charge going into the engine
was less than it should be, and the scavenging of the exhaust gases from
the cylinders was less than it should be. The final consequence of this
was a power loss.

There are a number of causes for power loss, if the compression is good.
Cam timing could be the problem here.

Hope this helps.

Regards,

John Rodgers
88 GL Driver