I am fairly certain that I am going to have to have my block rebored as there are two "tram lines" scored in No.2 cylinder. The English T Register sells pistons at Plus 060 thou - the question is, is there sufficient metal left in the block, or would I have to sleeve the bores?
I have been having really bad miss firing and low power on hills. I took the head off to decarbonise.It was very heavy carboned but has made no difference to the back-firing in the silencer.
I have fitted new plugs (X's), reset the trembler points, cleaner the timer, replaced the manifold gasket, checked for air leaks, tested the compression on each cylinder, but still no joy.
Any ideas or comments would be welcomed.
Did you use a hand cranked coil tester or a stobo spark when you reset the trembler point? If you didn't, and I assume you are using coils not a distributor, then the chances of setting the points correctly are low.
Is the compression the same on each cylinder? If so then that is not the problem.
Start the engine and using a screwdriver, short each spark plug one at a time and see how much the engine speed reduces with each short. You should find the troubled cylinder easily. Then move the coils to different locations and see if the miss moves with the coil.
If is does you have found the problem if not the you need to see if you have a short in the coils box or some were else.
If only had one scored cylinder I would buy one sleeve and then rebore to the size the other cylinders need
Compression figures? Is there anyone nearby who can lend you a set of coils to test with? Olivier Chabanne can tell you who is your nearest T neighbour.
Don't worry about the thickness of the castings, I have seen T's sucessfully bored to .125 over;)