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Old Apr 03, 2012, 05:51 PM
william hanshaw is offline
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William Hanshaw

MP Jet 040PB - Sleeve Orientation Question


Hello Guys...

I have a MP Jet 040PB and I've tried everything to get it running well. A friend has one that runs great and it's compression is about the same as mine, but we couldn't get more than about a very weak 2krpm out of mine. And swapping carbs didn't make any difference.

I'm wondering now about its sleeve orientation. My question is: should the small rectangular opening be turned to face the carb, or instead, should the larger round sleeve hole be oriented to the carb? Although the sleeve's larger, round hole is the same diameter as the crankcase's hole at the carb end, I still wonder if it should be that way because the sleeve's hole is beveled upwards, I'm guessing so it will direct the fuel air mix UP towards the combustion chamber. However, this orientation of the sleeve will place only the small rectangular hole to input fuel air mixture into the case.

Can anyone advise me on the correct orientation that the sleeve should be installed? The Czech engine seems to be in otherwise good shape and well-made...just want to get the little jewel running well! Sent it back to Ed Carlson and he said he got it running up to a respectable 8krpm, but I haven't gotten it to do that.

Thanks, Bill Hanshaw wghanshaw@sbcglobal.net.
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Old Apr 03, 2012, 06:24 PM
JohnAV8R is offline
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Bill, a few pictures would be helpful.
ie) a picture of the present orientation that doesn't seem to work too well.
John
Old Apr 03, 2012, 08:04 PM
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If it ran Ok for Ed Carlson then it is working OK. Unless you took it apart. If I remember right, the cylinder sleeve will tend to rotate when you loosen or tighten the cylinder top. So you have to use a clean wood or plastic stick through the exhaust to hold it still while you are tightening it up.

Generally on the engines that use the piston to control the intake, the lowest hole in the cylinder should match the intake tube nicely. The tallest port is the exhaust port.
The lowest hole is only exposed to the inside of the crankcase when the piston approaches top dead center and a little after. It is closed off the rest of the time.
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Old Apr 03, 2012, 10:19 PM
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Looked at it on Icare-rc's site, a very nice looking little classic diesel!Also saw that the MP JET .061 BB is availlable again(c/l&r/c) as well as some nice Super atom and Letmo reproductions.
http://www.icare-rc.com/diesel.htm
Old Apr 04, 2012, 03:54 AM
brokenenglish is online now
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Sticks, Tissue & old Diesels
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I think Earl is probably right. You seem to have a problem of cylinder rotation inside the crankcase.
I had this problem on a couple of repro Mills engines (so now I only use originals!).
Cut a clean strip of hardwood (ply will do) to the exact width of the exhaust ports. On the cylinder, make sure you know which port is induction and which is transfer (this should be easy just by careful observation, the transfer port will be slightly higher than the induction and should be facing forward). Insert the cylinder, making sure you have this correct fore/aft orientation. Then insert the wooden strip through the exhaust ports, right through the engine (in one side and out the other). This will prevent the cylinder from rotating while you tighten the head down really tight. You'll need a strap wrench to do this or, at a pinch (Ha-Ha!), you can use pliers WITH 1/16" soft alloy sheet between the pliers jaws and the head, but be very careful and don't try the pliers/alloy sheet method on an anodized head!
The whole operation shouldn't take more than 5 minutes. Let us know how the engine runs.
Old Apr 04, 2012, 04:38 PM
Chas is offline
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William, here's mine poodling along for inspiration

MP Jet Run.MPG (0 min 23 sec)


also gave the AM15, DC Sabre and ED Bee an airing; and why I prefer a 4k idle on a PAW 19, keeps it smooth and can idle indefinitely, and on a 10x5 the pitch speed is still only 20mph...I do not want to fly a Jackdaw slower than this! By contrast the 2.8k idle is staccato and can only be held safely for a minute or so in the air, if you hope to throttle up and warm up to full revs again. Although, a lot would depend on cowling, ambient temperature, etc.

AM 15
AM15 Run.MPG (0 min 41 sec)


ED
ED Bee Run.MPG (0 min 26 sec)


DC
Sabre Clip.MPG (0 min 55 sec)


PAW 19 TBR, burpy
PAW 19 2.8k.MPG (0 min 24 sec)


and steady
PAW 19 4k.MPG (1 min 5 sec)
Last edited by Chas; Apr 04, 2012 at 05:54 PM.
Old Apr 04, 2012, 09:01 PM
JohnAV8R is offline
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We all seem to like our little diesels


Posted before, but now another look.
One is soon to have company!

The crank cases are all made by a similar process, but the OT just seems a little smoother, or is it my imagination?

At the time (1974,5?) I did not realize that the OT was re-worked, a used MKIV Oliver, tuned by George Copeman in 1972, with correct lighting flash and date stamps on crank case.
Why anyone would re work an OT is beyond me.
John
Last edited by JohnAV8R; Apr 04, 2012 at 09:13 PM. Reason: added picture
Old Apr 04, 2012, 09:53 PM
Chas is offline
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Voices through wires? Ha!
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Quote:
Originally Posted by JohnAV8R View Post
Why anyone would re work an OT is beyond me.
John
Just a lightening of the piston and a smoothing of the ports. Olivers were sent out with "stepped" transfers, George smoothed and polished these with diamond abrasive. There is always someone who thinks that an extra 300 rpm will get that extra cut on a 20oz Dominator
Old Apr 05, 2012, 03:39 AM
brokenenglish is online now
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Quote:
Originally Posted by JohnAV8R View Post
Why anyone would re work an OT is beyond me.
John
John & Chas,
Another important mod made by George was that, as you know, Olivers were made for team racing, which means setting up the crankshaft bearings fairly tight, to avoid losing fuel through the front bearing. This costs a little power and a slight increase in rpm can be obtained by setting up the front bearings fairly loose. On a combat model, this also offers the added advantage of keeping the front bearing clean as it's permanently being washed by outgoing fuel!
So, if you notice that George's engine is losing a bit of fuel out of the front bearing, it probably isn't due to wear, it's meant to be that way!
Last edited by brokenenglish; Apr 05, 2012 at 03:54 AM.
Old Apr 05, 2012, 04:42 PM
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Question for Chas


Thanks for posting the videos, Chas. What props are you running on your Sabre and .040? I've only run mine using 8-4 wood propellers, but your video appears to show larger clubs being swung. Both are really sweet engines, not big on power, but very easy to start and tune. Just curious!

-Mark
Old Apr 05, 2012, 06:31 PM
Chas is offline
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Hi Mark !
Yes I'm a bugger for pushing the prop envelope, but frankly I would not usually use the 9x5 as I did in this case on the Sabre. However I was stuck with the aluminium anodised spinner (no propnut) and the crankshaft protruded into the nose, so I had to use a prop of maximum hub thickness - anyway I was curious to see how the engine would handle it. Not bad, about 5k, but it was way too much pitch. Normally a 9x4 I would regard as maximum.

The .040 is swinging a 7x4 , again about the limit I would think, but this time perfectly flyable.

The .19 is turning a 10x5 Graupner grey, AM15 and ED Bee both 8x4
Cheers Mark
Last edited by Chas; Apr 05, 2012 at 06:53 PM.
Old Apr 05, 2012, 07:55 PM
Moeregaard is offline
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Thanks for the quick response! I've never run my .040 with anything but an 8-4 Rev-Up prop, and it seems to like it. I'd planned to put it in a Tomboy, but the thought of losing what's become something of a collector's item keeps me from doing this. I have two Sabres, so maybe I'll build something around one of them.

-Mark
Old Apr 06, 2012, 03:55 PM
Dieter Doerr is offline
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Taifun HURRIKAN 1.48 ccm Diesel


Hello Guys

my new item, never used and complete.

Regards
Dieter
Last edited by Dieter Doerr; Apr 06, 2012 at 04:05 PM.
Old Apr 06, 2012, 08:16 PM
earlwb is offline
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Quote:
Originally Posted by william hanshaw View Post
Hello Guys...

I have a MP Jet 040PB and I've tried everything to get it running well. A friend has one that runs great and it's compression is about the same as mine, but we couldn't get more than about a very weak 2krpm out of mine. And swapping carbs didn't make any difference.

I'm wondering now about its sleeve orientation. My question is: should the small rectangular opening be turned to face the carb, or instead, should the larger round sleeve hole be oriented to the carb? Although the sleeve's larger, round hole is the same diameter as the crankcase's hole at the carb end, I still wonder if it should be that way because the sleeve's hole is beveled upwards, I'm guessing so it will direct the fuel air mix UP towards the combustion chamber. However, this orientation of the sleeve will place only the small rectangular hole to input fuel air mixture into the case.

Can anyone advise me on the correct orientation that the sleeve should be installed? The Czech engine seems to be in otherwise good shape and well-made...just want to get the little jewel running well! Sent it back to Ed Carlson and he said he got it running up to a respectable 8krpm, but I haven't gotten it to do that.

Thanks, Bill Hanshaw wghanshaw@sbcglobal.net.
I took a look at my PB-40 engine and the two rectangular ports are the exhaust ports. The transfer port looks round and it is higher than the intake port that is piston controlled. Also the intake port is not exposed above the piston crown, so it is lower than the transfer port.

In other words, The two rectangular holes were the exhaust ports.
The round hole pointed towards the front of the engine.
The round hole was almost even with the two exhaust port holes.
The other fourth hole faces to the rear and it is lower down, not as high up with the other three holes.

I hope that helps you out.
Earl
RCG Plus Member
Last edited by earlwb; Apr 07, 2012 at 10:10 AM.


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