Teymour

My Feedback: (15)

I bought a plane that had an os 61 sf in her. When I got the plane the engine was somewhat difficult to turn ( not just on the compression stroke but all 360 degrees) I pulled the head to take a look and see if there was anything that would account for this, and found nothing, other than a little bit of old fuel residue) . At that time I put some after run oil in the cyl and put the head back on.It seemed to move better. The carb barrel would not rotate and I put a few drops of fuel in the carb and it started moving right away. I decided it was time to try to fire up the engine and see if it would start. It was VERY difficult to get to start , but eventually did fire up. It ran for about 5 min and died. I tried to restart the engine and noticed that the compression was almost nil and that there was a very ruff feel to the shaft rotation. At this point I pulled the engine out of the plane and took it apart. Oh boy was I surprised at what I saw. Fortunately the piston and sleeve are ok but the ring and crank bearings are not. The ring also seems to be seized to the piston. I am looking for help to remove the ring and install the new one.I have also ordered new crank bearings and will be replacing them also.

Thank You
Teymour

sbd-5

My Feedback: (4)

usuall if you heat the piston up it will expand and the ring will loosen especially if caused by old gummy oil.put in an oven at 300 degrees for about 10 minutes use mitts so not to get burned.if that does not work use an xacto knihe blade under one of the ends and pry gently.you may have to break the ring and remove it in pieces this way they break easily as they are brittle.same with the bearings heat the crankase up the tap hard on a block of would and the g force should help move them out.

BillS

Cooking the engine in a crock-pot with antifreeze will likely loosen up the ring and also clean the engine. Also you might be able to salvage the ring.

Checked on rings for a 46 and a 50 last week and they are about $21 each. A set of bearings will also be about $20. Repair is often not cost effective.

Bill

sbd-5

My Feedback: (4)

depends where you get the parts i take old bearing to a bearing supply house in manchester so far they have had what i need for about half the price of the oem bearings.no failures either after many years.as for rings they is a gentleman on rcu that sells rings for any engine for about $10.00.he makes them himself.

Teymour

My Feedback: (15)

I have tried baking the piston to see if that will loosen it up, and it didn't help. Right now the piston is soaking in fuel to see if that will help remove the grime that is causing the ring to be stuck to it, and it seems that it is actually working. The ring was siezed solid and now it has just the slightest little bit of movement in it. I am keeping my fingers crossed to see if maybe the ring will be fine after it loosens up. As far as the main crank bearings, I am ordering a set from Boca. I understand that they make some high quality stuff and the bearings are only about 28 bucks for the pair. If anyone has any other suggestions that will help or if what I am doing will actually hurt things please let me know. I have rebuilt a few abc engines , but this is my first ringed engine to tear into.

BillS

If the ring is not horribly scratched, has spring tension, and the ring gap is not large it probably can be reused. The ring should be free in the grove. Bearings at $28 a pair seems high.

It should go with out saying that a ringed cylinder should be cleaned and very lightly honed with fine emery cloth. I am nursing two engines back to health now. With a little delicate tender loving care they will go another 100 thousand miles.

Bill

Teymour

My Feedback: (15)

Well , the fuel soaking did work. It freed the ring up and I found out that it had a crack in it. Oh well, there is one for sale here on RCU and I have already worked a deal with the seller. Now the only problem I have is how to ( or what is the best way ) to get the grime out of the ring groove in the piston without hurting the piston. I am continuing to let it soak in fuel ( heck it has worked well so far ) to see if it will continue to break down the grime. If anyone has any other suggestions, I would love to hear them. Thanks again for all the help.

Thank you
Teymour

kdheath

If you want it done right, new ring, bearings, screws, trued up head, whatever, for very reasonable charges, contact:
Frank Bowman
1211 N Allen Ave
Farmington, NM 87401-3568
(505) 327-0696
<[email protected]>

horace315

My Feedback: (15)

use the old ring to scrape the ring grove,file or grind one end of the old ring square so it will have an edge that works really good.

sbd-5

My Feedback: (4)

Frank Bowman ,i believe he is the one that makes rings for any engine even old out of production engines