Dan sez:
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When I disengage the
clutch the RPM usually dives to about 400 RPM then slowly builds back
up to 1200 RPM. Letting the clutch out in neutral adds another 200
RPM to the idle. On cool mornings the idle will fluctuate about 200
RPM constantly.
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Along with your idle problem, it sounds like you might have
an engine thrust washer problem. (I don't know about TR7s, but
Spitfires are infamous for it.) If when you have the idle speed
up to spec and all else seems well, but the idle still drops when
the clutch is dis-engaged (Clutch foot _down_), you might want
to pull the pan and check those washers/thrust face of bearings
before crank damage occurs. Another quick check would be to lever
the crank damper back and forth checking for end play (.004" comes
to mind; check your service manual to be sure.) A much larger than
spec reading (like .025") means a washer has worn down and fallen
out or the thrust bearing surface has completely worn away, which
will play havoc on the big and little end surfaces of the rods.
Aran (speaking from too much experience on Spits) Guy
guy@bevsun.bev.lbl.gov
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