I am helping a friend who just bought a 100 sort out a few issues with SEVERE
dieseling and a sticking throttle. Her car is a BN1 converted to BN2 4-speed,
and the prior owner mounted a 100-6 top-pedal box to accomodate a hydraulic
clutch (presumably a BN4 bellhousing).
the throttle linkage was sticking rather severely because the rear brass ball
joint casing was hanging up on the original asbestos shielding (the pedal
pivot is at the top, and obviously displaces the horizontal linkage a little
downward). we've cut away enough of the shielding to eliminate this
obstruction, and can set the idle down to 700-800. i had hoped this would kill
off the dieseling, but does not. nor does lifting up on the pedal with your
toes to assure the throttle is fully back.
the dieseling is really bad. you have to engage in 4th and the car wants to
drive forward, even when not engine temp is not very high. I have read past
threads, and noted several 'usual suspects'...
1. idle speed (not a problem here)
2. choke cable adjustment
3. leaking throttle plate shafts
4. timing
5. too high compression
6. carbon buildup
is there an order in which i should check these to rule out contributing
factors? are there any other causes of dieseling you've encountered.
the engine runs vigorously and has great throttle response. by history from
the seller, there was an engine build in the 1970's by his P.O., but we don't
know if the head was shaved more than appropriate. if it is a compression
issue, would using a tank of CAM2 prove/disprove compression as contributing
to the dieseling? if it is, can the problem be solved with having a steel shim
made to the shape of a head gasket? are the Dennis Welch steel gaskets thicker
so we could lower compression should that be the issue? there is no leakage
out the side by the motor number plate, so I don't see a need for one
otherwise.
allen miller
bn2/m
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