Almost in tears

[mickeytwonames]

I have a case of crankcase compression. I have changed the piston rings (+30) and shells. While in the shop there were two folk that has done their time on Moggies in the past. We examined the cylinders in the block - they didn't move nor wobble and not too much lip - when out there was a slight deposit of 'blow through' but nothing dramatic. I replaced the all parts and fired her up - Whoopee - no smoke from the breathers - that is until I drove home. Smoke blew out again.
Anyone got and advice or a replacement engined handy?

[kennatt]

from my expirience of over 50 years of working on engines,I can only think of a couple of times that pistons and rings have cured blowby,The only sure way is to have the block rebored and fit new pistons to fit the new size,after all if you have the engine in bits the slightly extra cost of a rebore has to be worth doing,the most expensive bits are the new pistons and rings,which you have bought anyway. But ,did you have the bores honed before fitting the new pistons,without doing this they will never bed in properly.And the bores need to be checked for ovallity,because if they are out of round,again you will never solve the problem without a rebore.

[bmcecosse]

As above - the bores need to be 'glaze busted' and you need to let the rings bed in. But it's rarely a long term cure.... Nothing beats a re-bore. Meantime - are the breathers linked to the inlet system correctly? The later HS2 carb with the direct 'suction' inlet is much better.