Hello,

I just received a new engine. As with all engines I receive I opened it up to check for burrs and left overs from the machining process.
Well, this one has got a lot of left overs in it... the stuff is everywhere!

So normally I just take the engine apart, wash everything thoroughly, oil it, and put it back together.

This one has got me baffeled. I am unable to remover the liner.
Normally heating up the engine case slightly with the hot air gun is enough to free up the liner. Sometimes when the liner fits tight it is necessary to cool down the engine before heating up the top of the case.

But this one won't move, no matter what I do...

BTW, the engine is an MVVS GRRT.

How do you top mechanics solve this?

Rudeboy....

....I put the toughies in a toaster oven, and turn it on broil....then keep
an eye on it for about 10 minutes. I let it get really hot..."till spit dances".

By that I mean....when you flick spit on it with your finger....it boils
instantly....and dances around as it evaporites....like a really hot iron.

Then grab it with a thick leather glove, and pry up on the liner.

I would inspect it carefully. Some engines have a pin to hold the cylinder sleeve.

I had one that had a large burr on the outside of the sleeve, that I didn't find until I cursed and swore a blue streak tryin' to get out...It was at the edge of a port, and left a gouge inside the case when it came out!

Rudeboy
Looks like we recieved the GRRT around the same time.

My engine was the same as yours, swarf everywhere and the liner was slightly twisted so that the liners exhaust port did not match up with the port on the case, there is no locating pin only the little slot where there should be one so I used this to my advantage and made a small C-spanner so I could twist it around then I cleaned the whole engine with ethanol, oiled her up and put it back together, also check the needle valve as I also found swarf there.
I don't think you should remove it unless there is a problem, just clean it out.

Loony,

My liner is slightly twisted too, but not so bad it will have ill effects on the engine's performance.

I dismantled and cleaned everything except the case, liner, crank and piston assembly... As far as I can see the is no crud left in the engine, and it turns freely (the bottom half of the stroke anyway), so I'll just leave it at that and pray...

When I was washing out the engine case the needle bearing fell out of the conrod, and somehow (don't ask me how) 1 second later the conrod had removed itself from the crankpin... I spent close to 1 hour just getting the rod back onto the pin without removing the liner... aaargh[:'(]

warm up the cylinder to about 250 degree F., place a ice cube or equivalent inside the sleeve to shrink it, and it will come out, unless it's pinned.

Pop it in the oven at 275 or 300 for about 10 minutes. That usually loosens things up.

I don't know if you have tried using a wooden Popsicle stick lodged in the exhaust port by the piston and gentling trying to push the liner out rotating the crank after heating the crankcase but that technique has worked well for me.

Hello!
Being the swedish MVVS importer I have taken apart some of these engines and never encountered one with a hard-to-remove cylinderliner.....
Most of the time the cylinderliner will come out if you just turn the propeller/crankshaft...the piston will then lift the liner a couple of mm...then its is easy to lift the liner with your fingers!

But one should never say never....I would warm the cylinder case with either heat-gun or if that does not do the trick...use a propane blowtorch.
Regards!
Jan K
http://hem.passagen.se/airracing