Thanks to everyone who replied to my previous posting. The general
concensus seems to be that too weak a mixture, poor cooling or too hot a
plug are to blame, although the plugs are correct (L87YCC), and it didn't
show any signs of overheating or weak running.
I got the lump out yesterday and finished off stripping it down. It appears
that the problems with that engine were more widespread, when I took the
pistons out ALL the top piston rings were broken. I'm beginning to think
that the ring failure could have been the cause of the demise of piston
no.3, if the second ring had broken as well then a lot of hot gases would
try to get past the oil control ring, resulting in molten aluminium. The
gap in the oil control ring was directly below where the piston failed.
The question is why did they fail? They were new (+30) hepolite pistons in
new bores.
Also does anyone on the list have any experience of unleaded head
conversions on these cars? I am considering getting exhaust valve seat
inserts fitted while it's apart, given the impending demise of leaded
petrol in this country.
Thanks in advance,
Keith Bennett triumph@compuserve.com
http://ourworld.compuserve.com/homepages/triumph/
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