[Vintage-race] Power Loss

[Gerald Brazil]

I had a weird problem once that was coil related. Over the winter I did some
"up-grading" of electrical components on an engine which was running fine at
the end of the season. I put a top of the line Lucas Gold coil on it and an
MSD capacitive discharge ignition. It ran just great until you got to about
4500 rpm and then it just went flat....no acceleration...couldn't even get
to 5000. After a frustrating weekend I took it to my tuning guru. He
listened to my story and then put it on his scope. What he found was that
the combination of the hot coil and the MSD system was firing at around
80000 volts but for a very short time. So short that it didn't have time to
really propagate a good fire in the combustion chamber. He put in good
quality off the shelf Niehoff coil and the engine was strong to 7500.

Some times you can have too much of a good thing.

-----Original Message-----
From: vintage-race-bounces at autox.team.net
[mailto:vintage-race-bounces at autox.team.net] On Behalf Of Rich & Liz
Stadther
Sent: Tuesday, May 22, 2007 9:29 PM
To: vintage-race at autox.team.net
Subject: [Vintage-race] Power Loss


Listers,

This past weekend I ran the SVRA event at Road America in a Dulon
Formula Ford.  The car was completely refreshed with new wiring,
engine, coil, etc.  It started out great, going very well, running
within 3 to 5 seconds of my fastest time at RA.  In later sessions,
it had a hard time getting to 7000 RPM.  The engine builder happened
to be at the race, and he was quite concerned, so he went over valves
and just about anything that may cause the problem.  The next
session, the car started out quick and slowed down.  Further checks
found the timing was off a bit, and it was reset to 38-40 degrees
total advance.

In the race on Sunday, although I had qualified dead last, the car
easily passed a few of the cars in front of me, but on the second lap
it started to slow.  After 3 or 4 of the 4-mile laps at RA, I could
see no one in front of me and no one behind, so I quit.

The engine builder of course was quite concerned and again reviewed
the engine he had built.  Timing was good, valves were fine, the
plugs looked great, the exhaust pipe had a nice color, and during the
race the engine sounded great.  But it did go slow.  Sometime after
the race, the engine builder noticed that I had hooked up the coil
backwards.  He said he'd never heard of that causing this kind of a
problem, but I am wondering if it caused the coil to heat up and the
engine to lose performance.

Has anyone on the list experienced a dumb mistake like this, and can
that be the cause of my diminishing performance lap after lap?  Over
the winter, everything was refreshed on the car.  It had a new Lucas
coil, which is now become a Bosch Blue.  The distributor is a
late-model Lucas from a Formula Ford builder.

Does anyone have any ideas what may have caused my slowly decreasing power?

Rich Stadther
1970 Dulon LD9