Just writing to say thanks to all for input, and providing an update on where
this all shook out.
It started with SU piston clatter and looking for causes - Henry Frye and
others suggested I'd better start with the basics and check cam timing and
lash. Turns out timing was off by a tooth plus four degrees (the offset
between the choice of bolt holes on the gear). The BFE M23-108 cam is now
dialed in to specs.
A leak-down test also gave perfect results - 5% or less across the board.
Thinking the ignition was not working correctly, I shipped the crank-triggered
ignition module that was in the car off to the manufacturer, and they confirmed
that it was not firing consistently throughout the rev range, and at 15 years
old or more, was not repairable. Several of you suggested going back to a
Lucas distributor (hmmm, really?) and I got a "rebuilt" one through Jeff at
Advanced Distributors. This is clearly better than new, both in appearance and
in re-engineering, and cheaper than almost any alternative. Jeff says there's
good durability and no points scatter up to 10,000 RPM , waaay above the 7,000
this engine is good for. Plus, I buy from a guy who supports our hobby and is
there for follow-up if needed. win-win.
The E-prod TR4 now runs and sounds great with no carb clatter, "idles" at 1500,
and revs nicely (in the garage, anyway) so the real test will be Summit Point -
Turkey Bowl - Thanksgiving weekend. Hope it's not snowing! After that, I'll
have to decide whether to take this car back to vintage specs or keep it around
as-is, with fiberglass flares and racing slicks.
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