Advice needed gang.
I just finished completely disassembling the motor on my 72 TR6 as part
of a restoration. I originally figured on rebuilding the head only as
all indications were that low compression was due to worn valve guides.
However, because I'm converting the transmission to an O/D unit I pulled
the engine/tranny out and, since it was out anyway, I decided it made
sense to check the lower engine. To make a long story short, when I
pulled the pistons out I found the top ring on the #4 was broken. Then,
when I pulled the main bearing caps off I found the thrust washers were
starting to disintegrate. All in all, it's fortunate I decided to have
a closer look else the engine would be a doorstop midway through next
season!
Now that I'm down to a bare block I'm trying to decide if I need to have
the cylinders bored out to oversize. The Haynes manual says to take a
piston sans rings, insert it 3/4" into the cylinder and measure the
clearance with a feeler gauge. Clearance should not exceed .010 in. I
did this test and found a .013 feeler gauge can be inserted about 3/4"
of the way down between the piston and cylinder bore.
Do I need to rebore? I'm already figuring to hone the bores because
I'll be needing rings but am worried about boring as I'll need new
pistons and the $$'s will increase significantly. Advice?
Mike Himelfarb
Director, Production Services Quality
Information Technology Department
Shoppers Drug Mart
(416) 490-2754
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