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[Rusty]

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[EddyR]

Rusty    If your motor is the ringed version I would replace the ring if it was mine. If it is not the ringed version a good crock pot cleaning is all it needs. You can do it yourself and then it will not get lost or damaged in the mail.
Ed

[FLOYD CARTER]

Ohlsson & Rice never made a .31 engine.  Their .29 front rotor has a plain aluminum  cylinder head on top of black fins.  Their .32 engines had a blue cylinder head (but only some of them).  A soak in a crock pot with anti-freeze will always free them up.

The only problem with these old O&R motors is the cylinder/crankcase gasket sometimes gets leaky.  There is no way to fix it because these parts are spot-welded together.  George Tallent of Arizona used to fix this problem, but he has passed away.  With old O&R engines, it is a crap-shoot!

also, all O&R engines had lapped pistons.  No rings.

Floyd

[Andrew Hathaway]

Actually, the Blue head is a .29.  The Orange/Red head is a .33.  There's also a Purple head .60, a Gold head which is a .19 or .23, and rumors of a Green head, IIRC.  There are plain aluminum headed versions of all of them, except I've yet to see a silver head .33.

I don't like the crock pot method.  It's too random and uncontrolled.  You never know if the antifreeze is going to discolor the case of the engine you're trying to clean.  Not to mention it often removes anodizing.  I prefer to use spray carb cleaner, or acetone and an old toothbrush to clean the exterior.  For sticky engines, I use a combination of heat (heat gun) and lighter fluid.  The heat softens the castor, the lighter fluid thins it out and frees up the moving parts.  I also pay special attention to the wrist pin.  Most of the time if the piston is stuck in the cylinder, the pin is stuck to the connecting rod.

I've got a FRV Blue head .29 and a .33... They're not very strong engines, about equal to a sad .15.  They wouldn't be my first choice to power a new plane, even when the selections are limited to ignition engines in the same size range.  At least they're light and they start easily.

[Brett Buck]

It has no size on the case.  It has O & R on the front of the venturi.  It has a red anodized head.  It has a lapped piston.  There are no bolts holding the cylinder or the head on.  I guess it is threaded like the Cox .049 or KB 61 twister? 

  I think, as Floyd mentions above, it's spot-welded.

   Brett

[De Hill]

As Floyd said, the cylinder is spot welded to the case. Do NOT try to remove the cylinder or head. They are not designed to be removed.

All you can do is to remove the three bolts and remove the front housing. Then if you are not careful, you will lose one or more of the needle bearings.

After you remove the front housing, you can then remove the piston and rod.

O&R went out of the model airplane engine business because the design of their engines didn't go well with glow plugs and glow fuel.

They had been the largest manufacturer of model engines in the world.

[Gerald Arana]

Rusty,

Reread Floyds post. "They are spot welded on"  Do not try to seperate the head/cylinder/ CC because you'll surely ruin your motor. If the engine is stuck, you may be able to put in the oven @ 250-300 degrees for 10-15 minutes and it should come apart-turn over. There are lots of people out there (no pun intended) who can help you.

Good luck, Jerry

[Brett Buck]

As Floyd said, the cylinder is spot welded to the case. Do NOT try to remove the cylinder or head. They are not designed to be removed.

All you can do is to remove the three bolts and remove the front housing. Then if you are not careful, you will lose one or more of the needle bearings.

After you remove the front housing, you can then remove the piston and rod.

O&R went out of the model airplane engine business because the design of their engines didn't go well with glow plugs and glow fuel.

    The 23 sideport will quite happily run backwards on glow, and can be running forward, backfire or otherwise glitch, and then run backwards as if nothing happened. That led to amusing consequences for my father and my late Uncle Donnie and their Mr. Mulligan.

     My sideport will run on low-nitro glow fuel only as long as you leave the battery on. It will keep running with no battery on 40% nitro, then the spot weld will let go, again with amusing consequences if you are a 16-yar-old running it in the garage.

    Brett

p.s. and for the record, this may not be a reliable solution, but when it does eject the jug, it can be glued back with JB-Weld and at least run for a while.

[Mike Keville]

...and if the cylinder head is anodized red it's a .33, not a ".31".  Ohlsson & Rice never made a .31.  O&R displacements were .19, .23, .29, .33 and .60.

[EddyR]

As a kid I used the .23 in RingMaster Jr's and the .60 in a Chief size plane. The .60's ran well on OK glow fuel.
Ed

[Randy Ryan]

Rusty, I build and restore engines, If you would like to send it to me I can fix you up. Some of the guys here can vouch for me, I'm not out to steal your engine.

[Steve Helmick]

Rusty, I build and restore engines, If you would like to send it to me I can fix you up. Some of the guys here can vouch for me, I'm not out to steal your engine.

Personally, I would clean it up with carby cleaner and after dry and if needed, heat it with a hair dryer or heat gun gently to loosen up the castor oil gunk. Then oil with Rislone or Marvel Mystery Air Tool Oil. But if I couldn't get results I wanted with that approach, off to Randy Ryan...USPS INSURED, both ways. FYI.  Steve 

[Randy Ryan]

Personally, I would clean it up with carby cleaner and after dry and if needed, heat it with a hair dryer or heat gun gently to loosen up the castor oil gunk. Then oil with Rislone or Marvel Mystery Air Tool Oil. But if I couldn't get results I wanted with that approach, off to Randy Ryan...USPS INSURED, both ways. FYI.  Steve 

Good point on the insurance Steve, thanks.

[FLOYD CARTER]

Another small point.  The aluminum cylinder heads on some O&R engines (whether color-anodized or plain) are staked onto the steel cylinder.  All O&R engines featured a blind bore.  The cylinder head only provides cooling.

Over the years, the crankcase/cylinder gasket gets brittle or it shrinks, causing crankcase leaks and even allowing the cylinder to be loose because the two spot welds act as a pivot for the cylinder.  If not too bad ,JB Weld can help seal the gasket.

As others have observed, never try to run an O&R engine on glo.  Sooner or later, the increased stress will cause the cylinder/crankcase welds to fail.

The smaller engines used a ball thrust bearing captive in a carrier.  The 60 engines had loose roller bearings, which are hard to assemble without some heavy axle grease to hold everything together.

I seem to have a soft spot in my heart (or in my head) for those O&R engines.  I guess I have 10 or 12 which I maintain in running condition. (one of them is mounted on a plaque made by De Hill.  The "Spirit of 46 Award".)

Floyd

[jim ivey]

hi Floyd member me? I have a 29 good condition.  no displacement marks on crankcase.  . I remember   plain , blue, red and I think green heads. the displacement was on the venturi. 29 and 33 of this crankcase is all i recall i had several. mine is missing the venturi restrictor.  Floyd may know more about the colors and displacements.

[Steve Helmick]

The only O&R I recall having apart was a glow .33, and it seems that the piston would "work" either direction (i.e., wedge/dome sorta thing on either bypass or exhaust side without hitting the head). So, be careful to mark it when you take it out, so you can get it back in correctly. It may be required to pull the wristpin to get the piston out of the cylinder. They are often stuck from old oil glop. Spray can carb cleaner should help.

We were trying to run ours, and it ran pretty gutless either direction the piston was installed. I would avoid taking it apart if possible, but that's always my rule for pretty much everything, from model engines to clothes dryers.  Steve

[jim ivey]

yep sometimes those rear intakes would reverse direction in mid air. ooops. we put spring starters on the Gilberts so they would be started in the right direction. I said to Bob, what if it reverses in mid air? he laffed and  replied, rhat ought to be fun to watch .