500 lb. koolaid man

Hi everyone, I have an old .35 control line motor that a neighbor gave me. I'm trying to take it apart for cleaning. A while ago I forgot what I did exactly but I put something under the plug(wd-40, mineral spirits or something) and let it drain back out after I moved the piston around a bit. This freed it up. Anyways, I haven't run it yet so I figured to take it apart today and really deep clean it with mineral spirits and/or wd-40. I can't get the piston out though. I have already tried to use soap, wd-40, and even put a heat gun up to it. This piston just will not come out the top. It slides freely until the top. I'll leave a couple of pics to show how far up I can get it. Please tell me what I should do to get it out. Please don't tell me to "pry it out" unless there really is no other way. I don't want to scratch the heck out of the insides.

Thanks.

Jim Thomerson

Take the liner out of the case. Put the front end back on the engine. stick a piece of wood, like a popcicle stick, in the exhaust. Heat up the case around the cylinder and push the liner out as far as you can by turning the crank. The wood will crush before you do any damage. Finish extracting the liner using delicate and non-destructive techniques. After you get the liner out, you can take the piston out the bottom.

500 lb. koolaid man

Any other methods? I can't find a popsicle stick or anything like that, although thank you Jim Thomerson for the advice. I've spent a long time trying to get this thing out, now I can get it flush with the top of the motor but that's it. I keep using liquid wrench and that helped a little but won't help any more.

I also gotta ask, is this normal? Or do they usually pop rite out?

Anyone know of anything else that might allow me to get this piston out?

Thanks.

cutaway

Some are manufactured with an intentional taper and won't come out the top. If its well worn, there's probably a slight ridge there. On larger auto engines machinists use a tool called a ridge reamer to knock that ridge off prior to honing.

downunder

Break a match into short pieces and use them to lift the liner as Jim suggested. Plastic tie wraps should work too.

It looks like you've got an Enya 35 which are a great old engine but I think maybe the piston is in backwards because I think the first photo was taken with the exhaust towards the camera so that baffle on top of the piston should be on the far side near the transfer port. It's possible the liner could be in backwards too so make sure it's fitted the right way when you put it all back together. If you're not sure, the top edge of the exhaust port is higher up the liner than the transfer port so it gets uncovered first as the piston comes down.

It's a cast iron piston with a steel liner so they need at least 25% all castor fuel but they last forever .

NEW222

I was in the same predicament a while ago with a Fox .35 I bought. I am sorry I cannot answer the exact question asked, but I too was not sure of this. I too could not figure out how to get the piston out so I finally broke down and bought a 2 qt. crock pot at Wal Mart ( $10 cdn)and did the coolant clean. It did wonders for my engine. I could not believe what kind of crud came out after 24 hours. Just a thought. If not, I hope you will get the answer you are looking for.

500 lb. koolaid man

I finally got it out. I tried the method Jim said using tooth pics that I found and that didn't work, so I sanded the inside top part of the liner. This along with soap and it came rite out. Soap didn't do anything before so I'm sure the wet sand paper was the trick, it looked a little rusted/corroded at the top anyways, and now it's nice and shiny

That's the good news, here's the bad news. I still can't get the liner out. I tried to pry it out at the exhaust port using a flathead but that cracked part of the casing[:@]. I think though that with a pipe on it the 2 pipes screws will be enough to wedge it in and as a result performing like it never happened(0% air leak) and also look like it never happened.

This liner might be impossible to get out[&o]. Anyone know anything safe to try?

Oh yeah I had an Idea, would 15 min. in boiling water clean all the parts? Or would they still be nasty and parts possibly warped to never work again.

Thanks.

500 lb. koolaid man

Fuji is the brand. So the baffle on the top of the piston should be on the opposite side of the exhaust? That means I would put the head back on the other way around too. I don't see how the liner could be on backwards, everything seems to be lined up properly and to me, the liner looks symmetrical anyways. I want to make sure everything is going to be properly re-installed.

"If you're not sure, the top edge of the exhaust port is higher up the liner than the transfer port so it gets uncovered first as the piston comes down." Sorry but I don't fully understand. When looking into the exhaust port, there is more liner sticking out from the bottom than the top. Maybe you can also determine if I need to try to turn it around.

Thanks.

cutaway

I think I'd just clean what can be cleaned and stick it back together at this point.

gcb

When you look into the exhaust port, you are looking through the slit in the liner. There is also a slit in the liner on the other side. The top of the exhaust slit is higher than the top of the transfer slit that sends fuel and air up from the crankcase. If, as you look into the slit, the one on the opposite side is higher, it is backwards and needs to be turned around.

You might try heating the crankcase and liner in the oven a bit to see if that loosens up the castor varnish.

George

500 lb. koolaid man

George, you mean put the engine case(with the stuck piston liner too obviously) in the oven for a while at about 200 degrees or so, take it out and let it completely cool down, and hope that that loosened the liner making it relatively easy to remove? Does that sound about rite? Maybe a higher oven temperature? I don't know what would work well.

Thanks.

Jim Thomerson

I would heat it up to maybe 300, then use oven mitts, etc, to take things apart while hot. The case should expand more than the liner and loosen up.

500 lb. koolaid man

Thanks! I'll try that.

500 lb. koolaid man

Thank you! I got it out. I figured I could use the heat gun unstead of the oven if I kept it on high, direct contact for a few straight minutes. When I felt my oven mitts getting very hot and about to burn my skin, and the engine smoking from old crud cooking I knew it was hot enough. I just pushed it out with a pencil, it slipped rite out. Thank you!

73Elsinore

Another way to do this is to stroke the piston down to BDC. Insert an old glow plug washer halfway into the exhaust port, just above the piston, so half the washer sits on the piston top and half the washer is sticking out the exhaust port. Now slowly stroke the piston up by turning the crank with an old prop installed on the motor. The piston dome will bear on the exhaust port in the sleeve by virtue of the glow plug washer being there. The washer is soft copper. This will bust the sleeve loose from the case. Works every time (at least for me!). Pete