as a few people mentioned any decent machine shop should be able to diagnose the problem pretty quickly

Don't you bet on it..........

I agree with Raymond.

Unfortunatly 4 machinists and at least 3 well recognised engine builders have seen my engines, not to menshion my own equipment. At the measurements the blocks were acceptable - they offered no obvious cause for the smoking.

All that we know now, is the each of my blocks (2) have the same problem, each smoking of the same reason, and the reason lies in the mahchine-work (boring, honing, grinding, planning).

Thats all.

One time I will find the problem, but not now. I am too tired, and have my working engine.

Maybe If I have used the engines for a longer period... a longer and more agressive running in... maybe...

But something is not right here.

The problem was deffiniatly boring-honing related. I have managed to get my 73mms engine rebored to 73.5mms, and it is running fine without any hint of smoke.

I accept this second engine a a proof.

I'm really glad that you have managed to get to the bottom of this. It makes you wonder how a machine shop can get a 1st class reputation then makes a complete mess of the job you give them. It's even worse when they don't recognise or won't admit to the problem. It would have been so easy so sort it the first time you stripped it and would have saved you so much hassle and expense. I'm wondering if I should be taking a sheet of really coarse emery to mine now - only kidding Maybe sitting for ages without being started has let it settle in

Thanks for the kind words.

I agree with You. Although this may sound strange after all this, I do not blame the machinist.He did something wrong, but nobody is flawless. If he will take the responsibility, and offer an acceptable compensation, I will accept that, and forget the whole thing. Nobody is without misstakes, except who does nothing.

I hope Your engine will be easier to sort out.