Solly Posted May 15, 2012 Share Posted May 15, 2012 I've just taken delivery of an OS 81 alpha 4-stroke. These new engines do not have the usual crankcase breather nipple, -I'm now wondering how to flush out the bottom end after running? Quote Link to comment Share on other sites More sharing options...
Codename-John Posted May 16, 2012 Share Posted May 16, 2012 you dont have to, they recycle all the oil to the exhaust Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 16, 2012 Share Posted May 16, 2012 Its an interesting point Solly......the Alpha engines have internal passageways to allow the crankcase to breathe & get rid of excess oil but that means you can't add a reassuring squirt of after run. I think that as long as you make sure you run the engine out of fuel on the ground so its good & hot (& dry) when it stops you will be fine...... I don't see that you have the option to do much else....... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 16, 2012 Share Posted May 16, 2012 It does raise the question about the best way to use after-run oil if you're in the habit of using it. Short of fitting a nipple in the backplate with a stoppable remote pipe (which I assume would invalidate the warranty) or removing the rocker box each time, there doesn't seem to be an easy way to do so. Having written this, I checked the OS manual on their website and it has the following advice: Do not leave unused fuel in the engine at the conclusion of a day’s flying. Accepted practice is to cut off the fuel supply while the engine is still running at full throttle, then expel as much fuel residue as possible by turning the engine over 5-10 seconds with the electric starter. Finally, inject some after-run oil through the glowplug hole and turn the engine over several times by hand. I'm not sure that I would be comfortable with removing the plug after every flying session - especially in a cowled application and even then, the benefits of doing so on a 4 stroke seem dubious When the engine is not to be used for some months (for example, as between flying seasons), a worthwhile precaution is to remove it from the airframe and, after washing off the exterior with alcohol (not gasoline nor kerosene), remove carefully the carburetor with intake pipe, glow plug and all silicone tubing and put them safely aside. Then, immerse the engine in a container of alcohol. Rotate the crankshaft while the engine is immersed. If foreign matter is visible in the alcohol, rinse the engine again in clean alcohol. Finally, shake off and dry the alcohol ,and inject some after-run oil in the glowplug hole and rotate the crankshaft several times by hand. Reinstall the carburetor with intake pipe and glowplug on the engine and keep it in a dry place after putting in a vinyl bag. Again, I'm dubious of any real benefit here unless the backplate was removed at the same time but there's no mention of doing so... Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 16, 2012 Share Posted May 16, 2012 Interesting advise from OS but like Martin I too am a bit dubious......constant removal & replacement of the glow plug is a sure fire way to wear the thread out & unless you leave the engine with the cylinder upright I don't see how much oil will find its way into the crank case to lube the crank/camshaft bearings....... The advise to immerse the engine in alcohol seems even more perverse to me as this will probably rinse any oil out of the crank bearings with no obvious way of putting anything back in there to protect the bearings from corrosion..... If I was to clean out my engines in this way I'd definitely remove the backplate & squirt a goodly amount of oil in the crankcase before storage..... Huh! OS eh....what do they know about model engines?? Quote Link to comment Share on other sites More sharing options...
Solly Posted May 16, 2012 Author Share Posted May 16, 2012 Thanks for the replies. I realise that the crankcase oil is expelled through the exhaust, but surely this will leave the bottom end in exactly the same condition as the old method, ie. a fitted beather nipple. Having experienced bad corrosion in a Saito caused by not flushing out I'm a bit dubious---. Quote Link to comment Share on other sites More sharing options...
JohnnyB Posted May 16, 2012 Share Posted May 16, 2012 Just going off on a bit of a tangent,so to speak, I bought a brand new OS55AX about 10 months ago,and it's been in its box and protective wrapping ever since. It has only been taken out to drool over but not run. Presumably, it would have been test run at the OS factory prior to despatch. So,my question is, should I periodically squirt in some after run or should it be OK until I fix it up with my Jitter Bug in about 3 months time. This problem with internal corrosion worries me quite a lot. I mean, you could over winter a model thinking that you've oiled it sufficiently only to go and start up for the first time in the new season and find out you've got some seriously damaged bearings with a variety of consequences. John. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 16, 2012 Share Posted May 16, 2012 Well OS do know a thing or two about model engines so lets hope they have done their homework.... All 4 strokes (except YS motors!!) lubricate their crankshaft/camshaft bearings & conrod in exactly the same way....with oil from the fuel blown past the piston ring. It is quite surprising how much oil does actually get past the piston. In earlier engines the crankcase was vented to the atmosphere & any excess oil went over the side. More modern engines have an external pipe linking the crancase to the inlet manifold to recycle the excess oil. With the Alpha series there are internal passage ways to allow the engine to "suck" excess oil from the crankcase, via the pushrods & head back into the engine via the inlet valve where it is "burnt" & chucked out of the exhaust To me the problem here is that if oil can get past the piston so can methanol & any by-products of combustion (which can include some nasty acids) can also get down there. Adding extra oil to the crancase after running will help protect the bearings etc from this mixture. But as I said in my first post I don't see what options you have.....there is no way of introducing oil into the crankcase directly. To my mind all you can do is a) live with it or b) add an extra breather nipple to the backplate & use that to add the oil (this should be sealed during running by the way) There is a third option of course....you could buy an SC/ASP instead...these have external breathers.... Send the OS engine to me & I will take on the burden of worrying about oiling the crankcase......I realise this is a very noble gesture on my part but it is one that I am willing to make to help a fellow modeller.... Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 16, 2012 Share Posted May 16, 2012 Johnny...if its brand new I'm sure OS will have taken steps to ensure the engine reaches you in perfect condition....I would suggest that no further action is needed. Two strokes are usually "better" in this respect.....as the fuel goes to the cylinder via the crankcase then the crankcase itself is fully purged during each cycle. After the last flight of the day, run the motor until its good & hot & runs out of fuel then add a squirt of after run into the carb & give it a quick spin on the starter & it will be fine until next time.... We should remember that the chemists who make oils for engines (model & full size) are aware of these sorts of issues & make oils that cling to & coat the components they meet thus depositing a film of oil over the inside of the engine......remember the Castrol Magnatec adverts where the oil clings to your engine like a magnet? Undoubtedly some marketing guff in there but the general principle is sound..... Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 16, 2012 Share Posted May 16, 2012 I was about to offer the same selfless gesture but Steve got in there first ! Well done Steve .I'm sure you have gone up in a lot of modellers estimation .If only I had got in there first Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 16, 2012 Share Posted May 16, 2012 Thank you Myron.....your recognition of the personal sacrifice I am willing to make for fellow modellers is very touching..... Quote Link to comment Share on other sites More sharing options...
Solly Posted May 16, 2012 Author Share Posted May 16, 2012 Steve, Myron,--It's good to know I'm amongst friends. If all else fails I'll take up your kind offer. Cheers! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 16, 2012 Share Posted May 16, 2012 Solly Glad you appreciate our concern .Steve didn't mention postage cost but I would be quite willing to pay it of course .How about that as a generous offer ( if you send a couple of props included of course) ? Quote Link to comment Share on other sites More sharing options...
JohnnyB Posted May 16, 2012 Share Posted May 16, 2012 Thanks Steve, I guess what I might have been getting at was - is there a shelf life of an engine before it needs re oiling etc?If you buy a new engine or indeed for that matter, say a new receiver battery, you have no idea just how long it's been "on the shelf" before you receive it and put it in your model. John. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 16, 2012 Share Posted May 16, 2012 For a battery most definitely.....NiMH cells sitting on a shelf for ages is not good. Personally I always put the date of purchase on my batteries so I know how old they are....obviously this doesn't tell me how long they were in storage.... Engines will last pretty much as long as you like on a shelf provided its not damp & they are oiled......excess oil will never hurt an engine in storage though so if your paranoia becomes unbearable you could always fill the engine crankcase with oil & then seal the whole engine in a plastic bag......if you do this then you must ensure that you get as much oil out of the engine as possible before trying to start it......otherwise a hydraulic lock & engine damage could well result. Oil is not known for its compressability after all.... A friend of mine used to work in an engine repair shop & had just rebuilt a truck engine. He asked his apprentice to "fill it with oil" & left him to it. Noticing that the apprentice walked back & to across the shop floor carrying oil cans quite a few times he wondered what was up but thought nothing of it until they tried to start the engine....it was locked solid.....the apprentice had indeed filled it with oil....right up to the bottom of the oil filler neck.....they had to drain 13 gallons of oil from the engine to get the level back to where it should be...... Quote Link to comment Share on other sites More sharing options...
Tom Sharp Posted May 16, 2012 Share Posted May 16, 2012 The OS Alpha range of engines have been about for a few years now (2006) so they must work safely or they would have been discontinued. The good news for anyone with concerns is, I have a new OS FS V 95 and its got a breather nipple just under the valve gear drive housing. Make of that what you may. Quote Link to comment Share on other sites More sharing options...
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