Mark Eden was good enough to let me drive his #42 Spitfire at High
Plains Raceway this last weekend but we just couldn't get it to run
correctly once the RPM got over 4000 when under load on the track. It
was fine in the paddock and on the grid reving easily to over 4000 RPM
but once I got on the track and under load it lost power and the dual
EGT gage on the #1 cylinder exhaust would drop to zero while the EGT
gage was reading 1100-1200 degrees on the #4 cylinder exhaust.
Basically the #1, and maybe the #2 also, cylinder was not firing at
all. It certainly felt like only 2 out of 4 were firing but since only
two exhaust pipes are monitored with the EGT system I couldn't verify
that.
We checked fuel pressure, fuel lines, spark plugs, changed rotor,
wires, distributor cap, relashed valves, checked timing, and few other
things I probably forgot but no joy. It dropped power going straight,
on curves, uphill and downhill, but once I got to the hot pits and
paddock under 4000 RPM it would come to life and the EGT gage read the
same on both sides.
So what else could it be? Advance mechanism in the distributor bad?
Valve float (we visually inspected them to see if any were broke)? And
why under load would something like this suddenly manifest itself when
there's no sign of a problem when not under load? And only on 1 or 2
cylinders?
Thanks for any suggestions.
Bud Rolofson
Extreme Parts Racing (more than just a haircut)
71 Spitfire MK IV Race Car #3
71TR6 CC57365 (Good 6)
93 Minnie Winnie Race Support Vehicle
77 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)
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