OS 40-H ????
11-29-2002, 05:20 PM
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OS 40-H ????
My uncle said he was cleaning out his basement the other day and came across a box of stuff that he wanted to give me. He was in the hobby 10 or so years ago.
He hands me a box with a SIG Kavalier Fuse kit in it and low and behold, a motor.
It is an OS 40-H. I did not come with a muffler. It is an airplane motor by the looks of it.
Looks in good condition and has great compression. Very clean. I cannot seem to find any info on this motor. Looks like the muffler is one that would just clamp on. There are no mounting holes to pass bolts through. Could be drilled though, which is a possibility.
Does anyone have anymore info in this little gem.
I have several airframes that could use this motor. I am looking to get some particulars.
Thanks in advance.
Cheers
P.S. I'll post a pic when I get home if that helps.
He hands me a box with a SIG Kavalier Fuse kit in it and low and behold, a motor.
It is an OS 40-H. I did not come with a muffler. It is an airplane motor by the looks of it.
Looks in good condition and has great compression. Very clean. I cannot seem to find any info on this motor. Looks like the muffler is one that would just clamp on. There are no mounting holes to pass bolts through. Could be drilled though, which is a possibility.
Does anyone have anymore info in this little gem.
I have several airframes that could use this motor. I am looking to get some particulars.
Thanks in advance.
Cheers
P.S. I'll post a pic when I get home if that helps.
11-30-2002, 02:47 AM
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OS 40 Marine
HI,
OS used to put out the MAX-40VR-M abc marine engine about 15 years ago. The carburetor is front mounted with rear exhaust exiting over the output/crankshaft. If it's a marine engine it should have a water cooled head. It will be solid (no cooling fins) with a couple of fittings for water circulation. They we're a hot engine putting out around 1.8 HP at 20,000 + RPM.
FLASH IT UP !
OS used to put out the MAX-40VR-M abc marine engine about 15 years ago. The carburetor is front mounted with rear exhaust exiting over the output/crankshaft. If it's a marine engine it should have a water cooled head. It will be solid (no cooling fins) with a couple of fittings for water circulation. They we're a hot engine putting out around 1.8 HP at 20,000 + RPM.
FLASH IT UP !
11-30-2002, 04:29 AM
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OS 40-H ????
Well.... it's definitely an aircraft engine. Ball bearing, probably with a ringed piston and not schnuerle ported. Someone will tell you all about it. It's in nice shape appearance wise. If it turns over freely, fuel it up and flip the prop. Happy Fly'n....
11-30-2002, 01:56 PM
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OS 40-H ????
That's a 1972 MAX-H 40 and was the last of that model. It's got a much larger transfer port than the earlier ones and the 40 is cast into the crankcase instead of being stamped onto a machined pad. It's a loop scavenged engine with one ring and most likely a single ball race at the rear. Although not as powerful as the later Schneurle engines they'll last a very long time, treated right.
Going by your piccie I'd say it hasn't been run because there doesn't seem to be any marks on the mounting lugs. That being the case, run it in very carefully, remembering it's a ringed engine. The original muffler was held on by a strap. Go to
http://www.osengines.com/history/osm...2-max-40rc.jpg
to see the engine and muffler.
BTW...the hole in the back of the crankcase just below the exhaust is where you remove the wrist/gudgeon pin. And good luck if you try it
Going by your piccie I'd say it hasn't been run because there doesn't seem to be any marks on the mounting lugs. That being the case, run it in very carefully, remembering it's a ringed engine. The original muffler was held on by a strap. Go to
http://www.osengines.com/history/osm...2-max-40rc.jpg
to see the engine and muffler.
BTW...the hole in the back of the crankcase just below the exhaust is where you remove the wrist/gudgeon pin. And good luck if you try it
11-30-2002, 02:15 PM
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OS 40-H ????
I had an OS Max 40 H years ago. I seem to recall it had two ball bearings in it. Had it on a Sky Tiger 25 with a tuned pipe. Talk about UP, UP and UP! Ran great until it, uhm, threw the rod. I seem to recall 16,000 rpm with the pipe, but don't remember the prop. Perhaps it was the rpm that killed it.
11-30-2002, 05:10 PM
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OS max-H
OS made the -S and -H at about the same time. The S was bushed the H had ball bearings. The -HP was the pylon racing version.
I got mine used but still unrun. I took it off a Sweet Stick and mounted it on a Midwest Aerostar .40 trainer. It pulled the trainer vertical for 50-60 feet at a time. I didn't try to pull higher as I was just learning and my instructor thought I was out of control.
After a few gallons of fuel thru it it still starts and runs well. Not as powerful as my KB 4050 and other real hot .40s but very respectable.
I got mine used but still unrun. I took it off a Sweet Stick and mounted it on a Midwest Aerostar .40 trainer. It pulled the trainer vertical for 50-60 feet at a time. I didn't try to pull higher as I was just learning and my instructor thought I was out of control.
After a few gallons of fuel thru it it still starts and runs well. Not as powerful as my KB 4050 and other real hot .40s but very respectable.
11-30-2002, 11:08 PM
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OS Max-H 40
Hey SilverEagle2; I have the instruction sheet for this engine. I also have it ready to go once I build a plane for it. It does have a strap one muffler. I can send you a photo-copy of the instruction sheet if you wish. Just send me an e-mail with your mailing address. e-mail address is: [email protected].
11-30-2002, 11:14 PM
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OS 40-H ????
I have one of these on a diamond dust, wow, what a screamer with a 9x6 prop. The mufflers for these are hard to come by these days, your best bet would be to watch ebay.
12-01-2002, 04:07 PM
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OS 40-H ????
Hi
I've been using a couple of OS .40H engines for a long, long time now. Mine have two ball races and that is all I have changed in about 200 hours running on one of them. Single piston ring. I run mine on a 9x7 apc in one small pattern model and the other on a 10x7 apc in a trainer type. They take the OS Type 703 muffler. This ia also used on the .35 plain bearing engine from that period. This has a strap with a keyhole slot at one end and a bolt at the other. Both these mountings are part of the muffler, not the engine.
Bob Boumstien who deals in used engines had a muffler on his November listing fo $18. He can be contacted by Email: [email protected]. If you Email him he will send a complete list by return Email.
Hope this is of some use
Andy Brewster
I've been using a couple of OS .40H engines for a long, long time now. Mine have two ball races and that is all I have changed in about 200 hours running on one of them. Single piston ring. I run mine on a 9x7 apc in one small pattern model and the other on a 10x7 apc in a trainer type. They take the OS Type 703 muffler. This ia also used on the .35 plain bearing engine from that period. This has a strap with a keyhole slot at one end and a bolt at the other. Both these mountings are part of the muffler, not the engine.
Bob Boumstien who deals in used engines had a muffler on his November listing fo $18. He can be contacted by Email: [email protected]. If you Email him he will send a complete list by return Email.
Hope this is of some use
Andy Brewster
03-06-2003, 04:02 PM
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So I got...
This motor running and it seems really strong.
I tached an APC 10 X 7 at 11800 rpm on the ground.
It seems to load up and quit at the low end though after sitting at idle. That and the top end seems to go up and down 100 to 200 rpm while sitting at full throttle.
Any suggestions as to why. Bad plug? Seems great though. I threw a MAC's one piece on it. Is made for that engine. Gives plenty of tank pressure as well. I do seem to have to run it rich. When I lean it a little, it starts to drop in rpm again. I just get alot of goo. I am running 20% oil 15% Nitro, so that could be part of it.
Thanks for the help.
Cheers
I tached an APC 10 X 7 at 11800 rpm on the ground.
It seems to load up and quit at the low end though after sitting at idle. That and the top end seems to go up and down 100 to 200 rpm while sitting at full throttle.
Any suggestions as to why. Bad plug? Seems great though. I threw a MAC's one piece on it. Is made for that engine. Gives plenty of tank pressure as well. I do seem to have to run it rich. When I lean it a little, it starts to drop in rpm again. I just get alot of goo. I am running 20% oil 15% Nitro, so that could be part of it.
Thanks for the help.
Cheers
03-06-2003, 05:20 PM
#13
OS 40-H ????
Sounds like it needs more time to break in. Remember, this is an older ringed engine. They should be broken in for several tanks in a very rich 4-stroke setting. Don't get this one hot during break in!
You may also need to use a glow plug with an idle bar to help the bottom end. The baffle on the top of the piston will direct the incoming air/fuel directly to the plug and cause it to cool off with the resulting loading up you are describing.
John
You may also need to use a glow plug with an idle bar to help the bottom end. The baffle on the top of the piston will direct the incoming air/fuel directly to the plug and cause it to cool off with the resulting loading up you are describing.
John
03-06-2003, 05:32 PM
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Thanks,
Won't that "4 stroke" mode spit alot of unburnt fuel out the muffler? If it is firing every other stroke but still gets fuel with every stroke seems I am only burning half a tank worth and wasting the other right?
I've done this before on my other motors, but have never really been clear on it.
Also, what happens if it gets to hot? Connecting rod bushings go bad or something?
Thanks
Cheers
I've done this before on my other motors, but have never really been clear on it.
Also, what happens if it gets to hot? Connecting rod bushings go bad or something?
Thanks
Cheers
03-06-2003, 06:12 PM
#15
OS 40-H ????
Yes, a lot of unburnt fuel is expelled from the muffler. This does a couple of very important things during break in. First, you are making sure the moving parts are receiving a ton and a half of oil. Very little chance for parts to gall. Second, the excess fuel helps keep the internal temps down while the parts are wearing in. Specifically, when the ring is seating in with the cylinder. If these parts get too hot, you run the very real risk of the ring seizing in the piston.
A few $'s of excess fuel useage will go a long way to protecting the engine during break in. Don't look at the fuel as being wasted since it's doing the job you need it to do which is protect the engine.
John
A few $'s of excess fuel useage will go a long way to protecting the engine during break in. Don't look at the fuel as being wasted since it's doing the job you need it to do which is protect the engine.
John
03-06-2003, 06:32 PM
#17
OS 40-H ????
Jason,
You are welcome. One more thing though. Don't apply this info to ABC, ACC or ABN engines. These engines need to be run in much closer to the same needle setting you would use to fly them. Cast iron lapped pistons OTOH, need to be run in like a ringed engine, but for an even longer period of time. Some, like the iron piston Fox's and an old Enya .35 I have, may take a gallon or more to break in to the point you can lean them out and fly them.
John
You are welcome. One more thing though. Don't apply this info to ABC, ACC or ABN engines. These engines need to be run in much closer to the same needle setting you would use to fly them. Cast iron lapped pistons OTOH, need to be run in like a ringed engine, but for an even longer period of time. Some, like the iron piston Fox's and an old Enya .35 I have, may take a gallon or more to break in to the point you can lean them out and fly them.
John
03-08-2003, 10:16 AM
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OS 40-H ????
Hi
I'll chirp in a bit on this running thing, having used these motors for a lot of years now. I think you have two problems here. These engines use an early type of air bleed carb which I have found give a couple of minor problems, both easily fixed. The hunting at top end can be caused by air leakage down the main needle thread. I stuff a short length of fuel tubing over the thread and the length is such that their is slight compression against the needle shoulder, hence no leakage. The other problem occurs at the low end with a well run in engine, as the engine runs in there is a lot less friction than when newish and I have found that the air bleed hole is not big enough to get a lean enough bottom end setting even with the restriction screw not covering the air bleed hole. I have drilled mine out about 0.3mm larger so I have full control with the screw. I also agree with the comments above about not going too lean at the high speed end. I set for a run that is just breaking into a full two stroke with the model horizontal, when the nose is pointed sky-wards this is then a full two stroke run and fine. Another point with these cross scavenged motors is to use an idle bar plug. This prevents the plug from getting swamped with any unburnt oil. Thats it. Hope the above helps a bit.
Cheers
Andy
I'll chirp in a bit on this running thing, having used these motors for a lot of years now. I think you have two problems here. These engines use an early type of air bleed carb which I have found give a couple of minor problems, both easily fixed. The hunting at top end can be caused by air leakage down the main needle thread. I stuff a short length of fuel tubing over the thread and the length is such that their is slight compression against the needle shoulder, hence no leakage. The other problem occurs at the low end with a well run in engine, as the engine runs in there is a lot less friction than when newish and I have found that the air bleed hole is not big enough to get a lean enough bottom end setting even with the restriction screw not covering the air bleed hole. I have drilled mine out about 0.3mm larger so I have full control with the screw. I also agree with the comments above about not going too lean at the high speed end. I set for a run that is just breaking into a full two stroke with the model horizontal, when the nose is pointed sky-wards this is then a full two stroke run and fine. Another point with these cross scavenged motors is to use an idle bar plug. This prevents the plug from getting swamped with any unburnt oil. Thats it. Hope the above helps a bit.
Cheers
Andy
03-09-2003, 06:14 AM
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Thanks all....
I have run several tanks through this one and it seems to get better every time. I have noticed I get a bit of fuel spitting from the needle valve area on the high end. I will try the fuel tubing trick. Every tank seems to get better and better.
Who makes a good idler bar plug?
Thanks again.
Jason
Who makes a good idler bar plug?
Thanks again.
Jason
03-09-2003, 10:04 AM
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OS 40-H ????
Hi Jason
On the plugs I've used the Fox 1.2 volt short Idle Bar for a number of years on this engine. SIG are a distributer in the USA with part number FOX4201. I tried the 2 Volt version but the engine was not very happy on this one. If your engine is on the new side I also found them a bit unreliable early on and reckon that one of my engines took about 6 hours to fully settle down. I also had some trouble with lacquer build up on the piston & liner when using a Castor based fuel. I now run on 20% Klotz super techniplate with 10% Nitro for my sport flying and this seems to sort this to a large extent, I did have to open the main jet a bit with this fuel.
Andy
On the plugs I've used the Fox 1.2 volt short Idle Bar for a number of years on this engine. SIG are a distributer in the USA with part number FOX4201. I tried the 2 Volt version but the engine was not very happy on this one. If your engine is on the new side I also found them a bit unreliable early on and reckon that one of my engines took about 6 hours to fully settle down. I also had some trouble with lacquer build up on the piston & liner when using a Castor based fuel. I now run on 20% Klotz super techniplate with 10% Nitro for my sport flying and this seems to sort this to a large extent, I did have to open the main jet a bit with this fuel.
Andy
04-05-2003, 10:41 PM
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OS 40-H ????
Hi, all! I have one of these for sale, good compression, complete, nice looking little engine...buy it price of $60!! Email me for details, it is posted on e-xxx. will GLADLY donate to RCU for its sale!!
