Roger 2 Posted March 25, 2015 Share Posted March 25, 2015 Hi all, The motor is mounted inverted in a WW1 type plane and has always run well, I have always ensured it was running rich, smokey on low revs etc. I have never run it lean, the plane is a typical WW1 lots of wires and wind resistance so the motor has to work fairly hard in a wind. It has also started to change engine note in flight. Suggestions on where to start and what to dismantle first, I am a reasonably mechanically minded "crinkley." cheers Roger Quote Link to comment Share on other sites More sharing options...
.. Posted March 25, 2015 Share Posted March 25, 2015 Sounds like the bearings to me Roger Quote Link to comment Share on other sites More sharing options...
Jon H Posted March 25, 2015 Share Posted March 25, 2015 Can you pop up a photo of the oil? it might be nothing to worry about. Also running the engine rich all the time wont do it any good, it should be leaned off to max power and then come back a few clicks just to play slightly safe. In fact if you have been running rich on castor based fuel your exhaust could easily be blocked with carbon which would explain a great many things! Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted March 25, 2015 Share Posted March 25, 2015 I would start off by taking the head off and checking for carbon, Also look in the exhaust port for a build up of carbon on the valve stem. A very good carbon remover is Betterware Non Caustic Oven cleaner. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted March 25, 2015 Share Posted March 25, 2015 Black oil residue is usually the result of aluminium fretting so before getting too carried away, check the exhaust pipe to head and silencer connections are properly tightened or for any contact between the engine and cowling etc. Quote Link to comment Share on other sites More sharing options...
Roger 2 Posted March 25, 2015 Author Share Posted March 25, 2015 HI all To recap I never use castor based fuel even in 2 strokes, always whatever engine, Irvine Contest 10. I am not a needle valve tweeker, set it up, peak revs, back it off and ensure tick over is smokey. I am thinking something seriously duff ( a polite word!!). I first noticed it when I noticed "dirt " in my fuel bottle, I use exhaust pressure to pressurise the tank and drain off at the end of flying and run off the fuel . So bits were getting from the exhaust into the tank. So which bit do I start on main bearings. Or the head as suggested? Seems odd for once to try and repair an engine rather than search for the bits and buy new. Edited By Roger 2 on 25/03/2015 13:55:56 Quote Link to comment Share on other sites More sharing options...
Jon H Posted March 25, 2015 Share Posted March 25, 2015 Contest 10 fuel contains 2% castor oil. To me everything is pointing towards castor build up in the exhaust, especially if the dirt in your fuel bottle is looking like tiny black bits of grit or soot The idea to check exhaust tightness is a good one as vibration+oil+aluminium does create a very black or grey/black oil that is quite obvious. But I don't think that is the issue in this case. If the bearings were that bad the engine would sound like a bag of nails Edited By Jon Harper on 25/03/2015 13:55:47 Quote Link to comment Share on other sites More sharing options...
Roger 2 Posted March 25, 2015 Author Share Posted March 25, 2015 Right Jon will have a play prob tonight.. . Edited By Roger 2 on 25/03/2015 14:07:44 Quote Link to comment Share on other sites More sharing options...
Jon H Posted March 25, 2015 Share Posted March 25, 2015 No problem. If you do want to check the bearings in a basic fashion remove the glow plug carb and backplate. You should then be able to see the bearings and if you turn the engine slowly past tdc of the compression stroke (when both valves are closed) you should be able to feel if the bearings are really rough and you will see if they are all rusted up Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 25, 2015 Share Posted March 25, 2015 The black oil may just be carbon deposits but do check for any metal in the oil . let the sun or a bright light shine on it . If it looks pearly or glitters slightly then it will be metal from a bearing etc.A quick check for bearing wear can be made by holding both tips of the prop and try rocking it back and forth if there is any play in the crank bearings you will feel it . Also check the cam bearings ,often forgotten and they get very little oil. A quick look in the cam box,( two cap screws on the side) will be enough to check them . If full of brown muck then change them . If the bearing have worn then the performance will suffer quite a lot . Bearings are available from any good bearing supplier . and a complete set will only cost about £15 . Quote Link to comment Share on other sites More sharing options...
Roger 2 Posted March 25, 2015 Author Share Posted March 25, 2015 Thanks very much for that, I will have a play. I have never stripped an engine since I was a kid. Must remember to have a clean/clear bench area ,now that is difficult !!!!😕 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 26, 2015 Share Posted March 26, 2015 Hi Roger .Its not at all difficult . Do make sure you have some decent allen keys though as cheapies will round off and possibly damage the screw heads. Also have a clean plastic box/tray available to put the parts in as you remove them .Good luck and let us all know how you get on. Hears a you tube film of a OS 52 FS being stripped down . The OS is almost identical to the SC so it should help . . Edited By Engine Doctor on 26/03/2015 10:39:50 Quote Link to comment Share on other sites More sharing options...
Roger 2 Posted March 26, 2015 Author Share Posted March 26, 2015 Thanks all, I did strip down the engine last night, and I did look at the OS52FS on you tube, ( thanks Engine Doctor). I was relieved at the ease. (I am a retired physicist not a mechanic) What I found was the bearings even the reduction gear ones on the cam were perfect, everything piston/ liner etc. There was a build up of carbon on the exhaust valve surface and stem and also the exhaust port to the silencer. So Jon and Peter were right . Iv'e cleaned it up best as I could , I am the sort who looses minute things so I didn't actually remove the valve. I have built it back up and sucessfully run it this dinner time. The only awkward bit was adjusting the "bleep bleep" valve /tappet clearances. So all the black is/was carbon from the exhaust being carried by the excess oil. I might run it without tank pressure when the weather is better. If you are interested in the plane it is on you tube (Rogers Eindecker) it aint fast !!!! Again thanks all Quote Link to comment Share on other sites More sharing options...
.. Posted March 26, 2015 Share Posted March 26, 2015 Great stuff Roger , no one likes engine problems but it is so rewarding if you do get one and solve it. Quote Link to comment Share on other sites More sharing options...
Jon H Posted March 26, 2015 Share Posted March 26, 2015 Sounds good Roger. just make sure the cam goes back in the right place Quote Link to comment Share on other sites More sharing options...
Roger 2 Posted March 26, 2015 Author Share Posted March 26, 2015 Jon Trust me after all the swearing, the cam is back correctly. lol. Quote Link to comment Share on other sites More sharing options...
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