Force Engine - Removing Liner?

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AJS - 23 Sep 2004 00:05 GMT

Help,

After having a Force .21 that appears to be on its last legs, I
decided to strip it down in a last ditch attempt to see if I can
salvage it. I have got so far but cannot remove the piston liner. I
have tried every trick in the book, including heat, cable ties, etc.
The thing moves about 0.04" and that's it. Now I have noticed what
appears to be a pin down one side between the block and the liner. At
first I thought this was simply an alignment device cast in the block,
but now I look closer, it looks like a steel pin. I wonder if this is
what is stopping the liner from coming out? But can't see any way that
this pin could be removed. Anyone know if this is a pin and if it
needs to be removed, and if so how?

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Mark Stevens - 23 Sep 2004 02:49 GMT

> Help,
>
[quoted text clipped - 9 lines]
> this pin could be removed. Anyone know if this is a pin and if it
> needs to be removed, and if so how?

Answer to that sounds like strip the engine down further and you will be
able to remove the pin. At least you can clean the whole engine out then.
These things have to be put in somehow so there is a way of getting them out
too.....without damaging the engine.

Just make sure you know what goes where when you dismantle it.........Give
the whole engine a good clean whilst you are at it and I'm sure you will
notice the difference when you reassemble it....... give it a new break in
period if you need to.......and yes I have done this on full size engines
and it works just as well...!!!

Regards.........Mark

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M78Ultra - 23 Sep 2004 03:11 GMT

Rotate the crank shaft?

> Help,
>
[quoted text clipped - 9 lines]
> this pin could be removed. Anyone know if this is a pin and if it
> needs to be removed, and if so how?

Reply to this Message

AJS - 23 Sep 2004 09:10 GMT

Thanks for both words of advice, but 1st, I can't break the engine
down further without removing the liner, as to remove the
crank/piston/conrod, I need to remove the liner (but I agree that what
goes in should come out - somehow) Secondly I cannot see how rotating
the crankshaft will help me, I have obviously rotated it to try and
"push" the liner out without any luck.

It may simply be that there is a ring of burnt fuel at the bottom of
the liner, but I suspect that this pin is the reason it is not moving.

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M78Ultra - 23 Sep 2004 19:03 GMT

looking at an ofna force .21 breakdown sheet ...it doesnt show any pin in
that area I can see other than piston pin
http://ofna.com/pdf/eng-force21-P4,blackT8.pdf
good luck

> Thanks for both words of advice, but 1st, I can't break the engine
> down further without removing the liner, as to remove the
[quoted text clipped - 5 lines]
> It may simply be that there is a ring of burnt fuel at the bottom of
> the liner, but I suspect that this pin is the reason it is not moving.

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M78Ultra - 23 Sep 2004 19:17 GMT

http://www.rcnitro.com/rn/articles/10imfix.asp

If all else fails contact the manufacturer.

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Will Hicks - 23 Sep 2004 21:05 GMT

If you can rotate the crankshaft you can usually lift the liner. Place a
glow plug washer(copper) into the top of the cylinder. Position the piston
to BDC and put the washer on top of the piston. Slowly rotate the crank and
capture the washer between the piston and the exhaust port. Make sure the
washer does not extend out further than the thickness of the liner.
Continue to rotate the crank until the piston is at TDC. You should be able
to pull the cylinder free of the crankcase.

If the cylinder doesn't move up, with the washer wedged in the exhaust port,
you may have to carefully heat the engine first.

Hope this helps a bit.

Will

http://www.willstech.com
http://snurl.com/2mn - Our eBay Stuff

> Help,
>
[quoted text clipped - 9 lines]
> this pin could be removed. Anyone know if this is a pin and if it
> needs to be removed, and if so how?

Reply to this Message

AJS - 26 Sep 2004 22:47 GMT

Just to let you all know, the liner is out and I have the engine
apart. I ended up creating a flattened stick from a wooden dowel, that
wedged in the ports. It took some force (no pun intended) but the
liner eventually moved.

I now need some advice on tolerences, so if you can help, check out my
next posting.

Thanks again for all your help.

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Model Forum / Radio Controlled / Land Models / September 2004

Force Engine - Removing Liner?