Thanks for all the good responses on piston/head clearance.
I am the guy who assked the question. Summary of responses so far says
do not go below .040 because of crank, rod, and piston deflection. I
especially appreciated responses from people who had tried closer
clearances who shared their ususally disasterous results.
My current engine is set up at .046 and that is always what I had done,
so the comments from the motorcycle guy were a real surprise.
One response questioned radical approaches for vintage racing. This is a
much debated subject. SCCA rules in the early 60's allowed removal of
metal from any engine component as long as its originality could still
be identified. That is what I still do, but with rod and crank failures
as prevalent as they are, and with no money, points, or trophies at
stake, most people do what they have to do, and Triumph owners
especially use Carillo rods. Some use billet cranks ($$$$$).
I pretty much agree with this degree of liberalization, but do not agree
with Porsches having 2.0 liter engine and disc brakes where there were
none. However, live and let live, I say, and when you pass me, make it a
clean pass.
Next question: I am new at this internet stuff. I have several more
questions to pose that I think will be of general interest. Is it best
etiquette for everybody to respond to the list so everybody can see all
responses, or would you prefer to respond to me and I summarize? I could
do that for the next four weeks while I am at home rather than at work.
I am recuperating from a (heart)valve job. My next question,
appropriately, will have to do with valve lift (automotive!).
Again, thanks for responses. This is the most intelligent list I've
found on the net!
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