Hello All,
Not quite 1/2A but I think it appropriate. I have a TD 0.09 which had the head well stuck. I tried the usual baking in the oven and for the first time ever, it failed. I then soaked it in transmission fluid and acetone for a week. I held the c/case lightly in the jaws of my vice (used wood either side). I still couldn't shift it until I slipped a long series socket over the (correct) cox spanner. Wonders it came loose!. When I started to rebuild the engine, I found the cylinder had distorted (curses!). So how would you guys have tackled this absolute pig of a tight cylinder, without damaging it? I posted here because it is the same system as for the smaller TD's. I have omitted the other tricks that failed!

Andrew.

P.S. See the wanted ads below, as I need a new cylinder!

The exhaust ports on that one are in optimum position!

Hi All,

Me too had exactly this same problem only one month ago. Same thing as you, removing tight glow head. Reassembled and piston jamming towards top of stroke.. To say I was surprised is an understatement as I am not a ham fisted twit. Cylinder must distort through exhaust port area.

Gary

Hi Ron,
I am sure it isn't a burr on the exhaust slot. I used the correct spanner. The socket didn't give much extra leverage, maybe 2 or 3 cms. It DID enable a much better grip. The binding comes in way past the exhaust ports. The trick of freezing is one which I should have worked out, I am a physicist! Just plain forgot what I was heating! I am certain that the upper cylinder region is distorted. I have had 0.49s with the dread burr on the ports, usually from young inexperienced kids that don't know better than not to stick a screwdriver into the exhaust slots! I have used swiss files to remove said burr. Sometimes rather a lot of material has to been removed! It doesn't seem to affect the running after it has been done!

Regards,

Andrew.

Andrew, I probably have a cylinder I can spare.  I keep forgetting to check.  In the meantime, try lapping the cylinder using the piston and whatever you use for compound.  The piston is nitrided and very hard, and the cylinder is relatively soft.  So you may be able to get the cylinder back in round without harming the piston. 

Hello Jim,
Thanks for that, I have been toying with the idea, but didn't realise that the cylinder was so soft (I suppose that is why it distorted in the first place!). Your input makes it a no brainer, I don't have a thing to lose, considering TD piston liner sets are scarce on the ground. It may take me a few days to do it as I have a pile of jobs waiting (my wife is in Australia and I have this list of job, you know how it is!
  Jim this may be a dumb question but how do you lap a piston in with a Cox type ball joint? No problem with pistons having a wrist pin , but,,,,,,,,,. I suppose you would need a miniature suction pad a bit like a smaller valve grinding tool? Now how can I fabricate or get one that is small enough?
  In case anyone is wondering why I wanted the cylinder off, well there was so much slop in the ball joint that I didn't dare run it for fear of self destruct. Amazingly it had very good compression, not in the least bit clapped out until I managed to do it!

Thanks Jim, I will report back with how I did it (?) and results!

Andrew.

Hello Jim,
I have always lapped pistons in by rotating them and moving them up and down. Never realised you could get away with just up and down. I never cease to be amazed at what you can learn on the forums!

Thanks Jim,

Andrew.

Hello Paul,
It was good to meet you at the British Nats. As for loosening the head, that wasn't the problem! It was getting the cylinder out of the crankcase. OK same solution, I am a physicist and SHOULD have known about the different coefficients of expansion. In fact I DO, but I put it down to the medication I am on!
  I have given Jim's lapping idea a good trial, but the distortion is too bad to do the job. Fortunately Jim has a spare cylinder so he has got me off the hook on this one. Thanks Jim!

Regards,

Andrew.