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Post  7Mile on Fri Aug 02, 2019 8:28 am

I was removing the glow head on one of my very first engines when (because I didn’t have the correct tool) the soft aluminum of the cylinder bent inwards, making the piston unable to pass through. The extrusions are barely visible but completely ruined the cylinder, any suggestions?
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Post  aspeed on Fri Aug 02, 2019 8:54 am

While it could be possible to take the burr off with a honing stone an a lot of patience, it is best to just get a new cylinder  while they are still available from EX Model Engines or Cox International.  (or used I suppose.  Shipping is usually more than the part)  Bee careful.  The cylinders are soft steel not aluminum. Broken cylinder. . . Uglytd11
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Post  7Mile on Fri Aug 02, 2019 9:28 am

That’s too bad I guess, thanks for the info.
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Post  getback on Fri Aug 02, 2019 2:14 pm

While ur ordering that gasket for the SBJ ... Cox inter . is out of stk?? so here you go http://www.exmodelengines.com/home.php?cat=267 Small Cox Logo Matt and them are Good people too !!
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Post  Oldenginerod on Fri Aug 02, 2019 5:27 pm

7Mile wrote:I was removing the glow head on one of my very first engines when (because I didn’t have the correct tool) the soft aluminum of the cylinder bent inwards, making the piston unable to pass through. The extrusions are barely visible but completely ruined the cylinder, any suggestions?

It would depend on whether you have burred the exhaust port or distorted the cylinder. If you were removing the head with something jammed through the exhaust then you may be able to tidy the cylinder up by carefully filing of scraping the burr off. Then again, if you haven't been able to remove the cylinder then that's going to be very difficult.

If you were cranking on the head and holding the crankcase and the cylinder has twisted and distorted, then it's finished- no chance of ever using that cylinder again.

Just remember, heat always helps when dismantling these engines.
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Post  7Mile on Fri Aug 02, 2019 10:49 pm

Oldenginerod wrote:
7Mile wrote:I was removing the glow head on one of my very first engines when (because I didn’t have the correct tool) the soft aluminum of the cylinder bent inwards, making the piston unable to pass through. The extrusions are barely visible but completely ruined the cylinder, any suggestions?

It would depend on whether you have burred the exhaust port or distorted the cylinder.  If you were removing the head with something jammed through the exhaust then you may be able to tidy the cylinder up by carefully filing of scraping the burr off.  Then again, if you haven't been able to remove the cylinder then that's going to be very difficult.

If you were cranking on the head and holding the crankcase and the cylinder has twisted and distorted, then it's finished- no chance of ever using that cylinder again.

Just remember, heat always helps when dismantling these engines.

Heat? Can you elaborate?
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Post  Oldenginerod on Sat Aug 03, 2019 3:26 am

7Mile wrote:
Oldenginerod wrote:
7Mile wrote:I was removing the glow head on one of my very first engines when (because I didn’t have the correct tool) the soft aluminum of the cylinder bent inwards, making the piston unable to pass through. The extrusions are barely visible but completely ruined the cylinder, any suggestions?

It would depend on whether you have burred the exhaust port or distorted the cylinder.  If you were removing the head with something jammed through the exhaust then you may be able to tidy the cylinder up by carefully filing of scraping the burr off.  Then again, if you haven't been able to remove the cylinder then that's going to be very difficult.

If you were cranking on the head and holding the crankcase and the cylinder has twisted and distorted, then it's finished- no chance of ever using that cylinder again.

Just remember, heat always helps when dismantling these engines.

Heat? Can you elaborate?

Warm it up. You can use a heat gun (paint stripper) or even a small gas torch. (keep away from plastic parts of course.) Castor oil acts like a glue and often makes it really hard to dismantle an engine. The heat softens up the castor oil gum and the expansion of the metal due to heat, followed by contraction as it cools, usually allows even the tightest head or cylinder to be removed more easily.
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Post  pkrankow on Sat Aug 03, 2019 7:46 am

If you can get the back off...pull the connecting rod off the crank then remove the whole jammed assembly.

These are TD instructions. OP did not state what the engine was.

The backplate threads in.  Clamp a piece of thin barstock that properly fits the slots of the backplate in a vise with enough sticking up.  Heat the back with a heat gun.  Wrap the rest of the motor in rag.  Then use body weight to keep the heated engine on the tool locked in the vise and walk around the engine to break it free.  1/4 to 1 full turn usually makes it come apart the rest of the way with much less effort.

Bubbling castor goo is the correct temperature.  About 250F

The case is the real value as the other parts can be obtained relatively easy.

Phil
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