Next installment in the Sprite that sounds like a Diesel.
The mystery is solved, it was indeed excessive piston to bore clearance.
The manual suggests between .002" and .003". I have between .006" and
.007".
(Question: Is the figure in the shop manual the clearance you measure with a
feeler gauge, or is it a clearance that is all around the piston, so that I
would have to double it to compare to my finding?)
I measured all 4 bores and they are all the same.
The bore diameter is the only thing I didn't measure when I assembled the
engine. At the time I didn't want to remove the rings from a piston in fear
of breaking them. I wish I had done this.
I had taken my block and pistons to an LBC resto shop that then had their
regular machine shop do the work. I'll call the shop on Monday to see what
they say.
Damn. I should have sent it all to APT...
If I have to put it back together as is, would STP or Engine Restorer help
in any way?
Thanks again to everyone who helped with their suggestions.
Ulix
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