balsa brain

I am brand new to this conversion thing and despite reading most of the threads I have not seen how to completely take one of these engines apart. I have a Ryobi 31cc and a Poulan 32cc that I took out of trimmers that had other problems and was not worth the effort or money to make right. I have both of these engines broke down but can not figure out how to get the crankshafts out so I can do a bearing replacement after a anti freeze bath in a crock pot. I am sure this is something that is simple but is something that I have never done. I would appreciate it if anyone would chime in here and let me know how this is done. I am basically dumber than a can of rocks on this one. Thanks in advance.

Bill

Flathead

My Feedback: (11)

Well, a press is always handy for the removal of cranks, but not everyone has a press lying around just in case. To overcome this failure on my part, I have had success with the following. Place the nut on the end or the crankshaft to keep from battering up the threads, Place the crankcase on a firm surface (I use a flat piece of heavy iron) usually I put a thin piece of hard wood between the iron and the crankcase, and using a rather heavy hammer drive the crankshaft out. Thisd has worked for me, "CAUTION" Keep your fingers out of the way. It helps to keep the neighbors from hearing your ability to cuss while the blood blisters grow. Flathead 4

Ralphbf

My Feedback: (27)

It's important that the crankshaft hangs free when driving it out of the case.

balsa brain

Flathead, thank you for you response. I guess I need to ask some more questions.

1. If I get them out like that how do they go back in? I guess I could find a shop that had a press and get them to get it out and maybe put it back but that is kinda iffy.

2. The Ryobi was simple in that when I took the jug off the piston came right out. It has two rings and from reading the threads on RCU I take that to be good. The Poulan on taking the jug off, I could not get the piston to come out. There is something holding it and so far I have not been able to see what that is. I also want to replace the rings.

3. I will be buying the conversion parts from Jags.

The reason for doing this is that I have always wanted to design and build a plane of my own. If all goes well it will be something high wing,symetrical, and maybe about 80 or so inches span. I am just getting back into rc after about a four year hiatus. I left Florida to attend my Fathers funeral in Tenn and had all my rc stuff stolen while I was gone. That took the wind out of my sails until now and the only way I am going to get back in is with a conversion and an airframe of my own design, win, lose or draw.

Again,Thanks much

Bill

andrew66

I found that putting the case in the oven for a bit will help with removal of the bearings and shaft. I heat it at 350-400 for a few mins. Just like with a glow engine.

Edwin

My Feedback: (2)

I got caught using the oven. Hell has no fury like ... well you get the picture. I use the antifreeze crock pot to clean then remove the bearing if I have to. Crock pot to heat em up when I reinstall also.
Edwin

tim220225

My Feedback: (4)

Go down to a Harbor freight store or the like in your area and buy a small arbor press. I would not take the chance and beat a precision bearing out or in with a hammer. You run the risk of damaging the cage or the races. They need to come out square and go in square to the case. When I build or rebuild an engine I use a light oil to pre-lube the bearings so that they don't run dry during the initial running of the engine. I also use the same oil to lube the cylinder walls. Good luck!

rangerfredbob

My Feedback: (13)

for our purposes a garage sale toaster oven would be sufficient...

arbor presses at harbor freight are super cheap, like around $50

balsa brain

Thank you Ranger, I think my wife down in her building has a toaster oven that she has put up for her yearly yard sell that has yet to happen. I think I can get that easier than trying to sneak the engines into our oven.

If I put the engines in the anti freeze bath, bearings and all, will the bearing be hurt any? They seem to be smooth as they are.

Thanks,

Bill

balsa brain

I went to a thrift store and got a big crock pot for $4.00 and a toaster oven for $2.00. The pot is big enough that I have both engines in the antifreeze now. I will go to Habor Freight tomorrow and check on one of the presses.

Thanks,

Bill

w8ye

My Feedback: (16)

antifreeze does not hurt bearings

balsa brain

Thanks

andrew66

once it comes out of the antifreeze bath, immediately try to remove the bearings. I will be alot easier.

balsa brain

Well, I took the engines out of the hot tub this morning and with a little brushing, they both cleaned up pretty good. However the Ryobi has both rings broke and maybe a scored cylinder wall. I need to go get some fine garnett paper to polish it a bit to see if it's worth messing with anymore. The Polan I will have to wait and see when I figure how to get the piston out.

After having spent a lot of time reading this conversion thread, I think I am going to go after an Echo on the auction site. I have a few of them on my watch list now. From what I have read they will be lighter and maybe a little stronger. I have not checked for conversion parts for them but I assume they are to be found.

I would like to thank everybody that replied to my questions and to say that it is people such as yourself that makes this, for me, the goto site for anything rc.

Bill

av8tor1977

My Feedback: (6)

On that Poulan, if you turn the engine upside down with the cylinder pointed downwards, you will see four bolts that hold the crankcase together. You remove those four bolts. The crankcase spits into two pieces, one having the cylinder and one just a kind of half round cap. The cylinder is actually part of the upper crankcase half.

When looking for used engines, always take the muffler off and look into the exhaust port if possible. Usually that's the first place that gets damaged on a two stroke engine. If things look nice looking into the exhaust port as far as piston, rings, etc., then usually the engine is ok.

AV8TOR

balsa brain

Thankyou,AV8TOR, I will go outside and check that out now. I have 22 minutes till the Jaguars start their losing ways for this year.

Bill

balsa brain

Half time Indy 7, Jags 6, Incredible if you happen to be a Jags fan

Apparently what I have is not a Poulan, simply because it is not coming apart as avator said. I can't find any bolts holding it together.
The cylinder came off the case using a #27 torx bit going down through holes in the cooling fins. The cylinder is not a part of the case.
The muffler is held on with springs. The rod is a single piece with a roller bearing at the crank. Rear intake and rear exhaust.

I would post pictures of the engine but I don't have the camera software on this computer and I put it somewhere where I could not forget where it was. Right.

Again,thanks

Bill

rangerfredbob

My Feedback: (13)

the poulan 32cc trimmer and blower engines are about the same as a ryobi, are you saying the piston is stuck in the cylinder after you got it loose? it sounds like you just have a ring stuck in a port, take the muffler off and see if the ring is stuck in the port, if it is you should be able to push the ring into the piston and get it apart, I believe the transfer ports are just slots so it shouldn't be able to get stuck in there.

the poulan saw engines come apart like Av8tor mentioned

balsa brain

I got the ring to go below the ports so it was something else holding it up. Anyway, I put the top of the cylinder in my vice with gentle pressure and put a dowel rod through the rod bearing any pulled sharply on it and got the rod and piston out like that. I think this one is also not going to make it to the air as it also has score marks, worse that the Ryobi. The Ryobi might clean up. It was in a Troy Bilt TB 70SS trimmer and I did get it to start, just not stay running for over a few seconds. I tried a carb rebuild on it, my first attempt, and probally just did not get it right. I have learned alot about Walbros since then. I may tinker around with the Ryobi some more but think in the long run, I should just try to win me an Echo and go from there. New would be good. In one of the threads a guy that apparently builds them for sell said the 23.6 is the way to go. I am not sure how to find the model # for that one but will figure it out. Maybe.

Again, thanks much to all of you that tried to help me.

Bill

av8tor1977

My Feedback: (6)

These little engines are too easy to find and too cheap to fool with a bad piston and/or cylinder. It will just give you grief. Keep looking, and before you know it you'll have dozens of little engines. Check small engine repair shops. They often have an area where they store machines that customers never came back for, etc. and will sell them cheap. Yard sales and garbage dumpsters are fair game, and I know one guy that made a deal with his garbage man to bring him yard work machines. Before he knew it he had more than he knew what to do with. They are out there....

AV8TOR

balsa brain

Thank you AV8TOR, just from reading these threads I have figured this out. The ideal of making a deal with the thrash man is a new one and i will try that one out. I think I am going to go the Echo route and have got a couple of messages from people trying to help me. Some of the best people I know I met at a flying field and the people in here have all spent time at one or two or twenty five. Good folks and thanks.

Bill

Ralphbf

My Feedback: (27)

You can't go wrong with the Echo trimmer engines.

Like av8tor said hit up some repair shops, tell them you want to make an airplane engine and smile a lot.

I pulled about a dozen out of the first place I hit up.

Over half had good pistons and cylinders.

Get enough good parts and you can make a twin cylinder 50cc engine.

balsa brain

Thanks guys and I will see what i can drum up. This conversion thing is just to interesting for somebody like me not to presue. It may be a few days but will let you know what I turned up.

Thanks,

Bill

balsa brain

Well,I have been messing around with the Ryobi some and got it cleaned up pretty good. The cylinder actually looks good with no scratches at all. The chrome still is shiney from top to bottom. I did my "machine" work on it with a grinder and a dremel and that IMHO looks good. I am going to the auction site to get a new Walbro for it and am looking for a wt499, wt144, wt 197 or a wt167. I would appreciate some advice for this part. I was going to start hogging out the muffler but am not sure how to go about it. It looks like it does not come apart and I am not sure how I can get anything to come out without being able to open it up. Some shared knowledge would be very helpful here to.

My wife and I went over to my sisters and brother-in-laws house to eat last night and I was telling Dennis what I was doing with these little engines and told him I needed to find an Echo cheap. As it turns out their next door neighbors just sold their house and bought a condo and gave them all their old lawn equipment as they would not be needing it anymore. Turns out that the weedeater they got was an old,I guess, Echo SRM 2501 and he gave it to me. That was easy and cheap. It runs and starts easy on a pull or so. So I will check around as time premits and see what I can buy to made this an aero plane motor.

I have read posts where people are saying that this conversion thing is getting to be not cost effective with the Chinese engines coming onto the scene at a very reasonable price. I can see that but it is fun just tinkering around with these engines and making them something they were not meant to be. I have already got several hours in the the ryobi and can't wait to get the parts together to finish it up and hopefully get it started. I going to order some Bowman rings in the next few days. Anyway, thats where I stand for now.

Thanks much,

Bill

w8ye

My Feedback: (16)

I doubt you will find a WT-167.

You are supposed to be looking for a WA-167 which was the Zenoah G23 Airplane gas carb before the g-26 came out