Howdy all,
I was in Hilton Head for an ethics symposium this weekend (another all
expenses paid conference by the education dept.) I got to see a few nice
Midgets - one was a white rubber-bumpered car being flatbedded north on I-95
in SC on Thursday afternoon - looked like a good car. The other was a
pristine burgundy rubber bumpered Midget driving through the plantation
where we stayed...I would call the car "showroom", but that wouldn't do it
justice. It looked so good, it was almost fake.
I got back today and replaced the blown-out middle resonator on my MGB
with a piece of straight pipe. It went in very well, and afterwards I began
to tune the car up just a little to try to get rid of the backfire problem I
had. On the first run, the car ran great - the exhaust note has changed
from a terrible roar to a nice growl, and I can talk to my passengers again
while driving! The backfire, however, was still there. I played with the
timing and mixture with no real results and started to think about the
dizzy. The car originally had the 25D4 in it, but I replaced it with a much
better 45DE4 in it - the electronic box being an Allison unit. I had
attached a vacuum unit to the 45DE dizzy in August, around the time of my
backfiring problems...Hmmmm. So, I pulled the vacuum line and plugged it
while my friend revved the engine. No backfire! I have two guesses as to
what might have happened: The vacuum unit had torn sometime since I
installed it, or there's another vacuum problem. Do I remember someone
saying that some dizzies had vacuum advance while others were vacuum retard?
Would that be the problem - the dizzy wasn't correct for my carbs?
Either way, with this new-found knowledge, we jumped into the car and
went on a little run. Now, keep in mind that we pulled this muffler in the
school parking lot! We rounded the first turn out of the lot, and I put the
pedal to the floor. Normally, the car would accelerate and pin us into the
seat, with smile slowly spreading. This time, the tires screamed horribly
and we spun around in a 180! As the dust settled, my friend who was
assisting could say nothing more than, "Holy S**t! We fixed it" and I could
only mumble in amazement that "My MGB NEVER did that before!" We continued
on our run, and the car performed great - we could hear the radio, though
there was still a little backfire caused by air leaks in the exhaust.
There were sections that we hadn't replaced that have some small gaps in
them, which I believe causes the remaining backfires. But, the car sounds
and runs amazingly better now! I'm impressed!
Anyway, sorry for rambling, I thought that my new found information
might help others who play the mix and match parts game...Enjoy!
Michael S. Lishego
http://www.geocities.com/MotorCity/Speedway/3706/
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