Russ Posted January 11, 2014 Posted January 11, 2014 Ok......upper cyl lube in particular, are they just money out the exhaust pipe,or genuine assistance to engine longevity/ health. If..........they are benificial, are they to ALL fuels ( Mogas / avgas ) Vev .......where are you.
facthunter Posted January 12, 2014 Posted January 12, 2014 Russ, generally the aviation scene doesn't get into this stuff. If you add an oil to the fuel it must not lower the octane rating for one thing. Ordinary engine oil will so if you had an engine consuming a lot of oil even if only on one cylinder it could cause it to fail through preignition/detonation effects. IF I was running a Jabiru engine I would add a very small amount of a good additive that won't make the fuel go stale quicker or affect the octane rating. (about an egg cup to each tank of racing outboard). But you didn't hear it from me. It mixes well with avgas or mogas and gives a bit of assistance in preventing cylinder corrosion. Nev 1 1
jetjr Posted January 12, 2014 Posted January 12, 2014 Some talk a while ago on using flashlube at low rates prevented bore corrosion Guys around Adelaide if i recall
jetjr Posted January 12, 2014 Posted January 12, 2014 What about oil additives like flush to keep engine cleaner and rings free? This one http://www.costeffective.com.au/show_product.php?ItemId=27 Works well in engines with carbon build ups, oil really does stay cleaner after treatment
facthunter Posted January 12, 2014 Posted January 12, 2014 I have never found a treatment that will remove carbon from piston ring grooves even with them removed from the engine if they are baked hard enough, and I have tried plenty over the years, let alone work inside the motor with it running for a short while.. Prevention is better than cure here. Big sceptic about that kind of treatment. Use a good oil and change it often and watch the engine temps. Climb faster (airspeed) if required. (Don't fly into a hill to do it.) Nev 1
Russ Posted January 12, 2014 Author Posted January 12, 2014 Yea.......over many ,many yrs have heard from folks that swear by "additives" but never heard/read from authorative sources real feedback (good or bad info) Upper cyl lube in particular I,m interested in. At this moment Lame chap is honing cyls,replacing rings, plus cyl head job etc to my 160, (couple of cyls were down in comp, and I wanted to know exactly what was going on within) hence pull pots etc off and have a look. (Stuck rings being the devil, in 2 cyls) Apart from that, all was good. Russ
facthunter Posted January 12, 2014 Posted January 12, 2014 They get pretty hot and sometimes get a scratch or two which I put down to scarcity of oil film and STEEL being the cylinder material is more critical to lubricate. Jammed rings not good. A blowby check will show that..Nev
Old Koreelah Posted January 12, 2014 Posted January 12, 2014 ... hence pull pots etc off and have a look...Russ While they're off Russ, might be a good time to install CAMit's forthcoming oil injector kit. Ian Bent <[email protected]> emailed a prompt and informative reply to my enquiry. They're sure having a go. Because my heads are not off, and hopefully won't be for a couple of years, I am looking at installing a simple short-term solution; a nozzle to spray 2-stroke oil down the throat of the carby before shut-down. Neater and probably more effective than the weak oily fuel it currently gets. I just noticed the beginnings of surface rust on the outside of my barrels, so I'd better hurry up.
Camel Posted January 12, 2014 Posted January 12, 2014 Russ, many people use different oil than jabiru recommend with great success, also Shell have done tests using other oils in Jabiru experimental engines which were positive, I can not tell you any more, you need to ask around but no one but Jabiru can recommend a product to use. Rings start gumming up between 150 and 200 hours with aero oils, after that theres no point using any other product. Remember you have to use what the manufacturer recommends in a factory built plane.
Downunder Posted January 12, 2014 Posted January 12, 2014 I've always thought the "Yamalube" range was good. Used the "Ring Free" on my 2 strokes....... http://www.yamaha-motor.com/yamalube/categories/additives/
Russ Posted January 12, 2014 Author Posted January 12, 2014 Russ, many people use different oil than jabiru recommend with great success, also Shell have done tests using other oils in Jabiru experimental engines which were positive, I can not tell you any more, you need to ask around but no one but Jabiru can recommend a product to use.Rings start gumming up between 150 and 200 hours with aero oils, after that theres no point using any other product. Remember you have to use what the manufacturer recommends in a factory built plane. Jab say shell aero 100, so that,s my oil. ( aero 100plus ) this 24 rego ruling can be frustrating at times, especially when owners collectively run up huge hrs, and proven "mods" on 19 reg machines, are not permitted on 24 machines. Things like better suited oils, better engine cooling, and more......frustrating. 1
DrZoos Posted January 12, 2014 Posted January 12, 2014 be careful carbon build up due to additives including oil, especially if castor oils. Also dont forget any additive may also affect plastics, glues, resins and other soft materials in your fuel system.
Russ Posted January 13, 2014 Author Posted January 13, 2014 Russ, what hours did your engine have on it ? At around 350hrs I noticed a softness in 2 cyls, especially when cold, but improved a lot when hot, but still soft. Performance was a tad down generally. I,m glad we have done this exercise, couple of minor defects showed up as well, ( oil seepage underside 1mag ....internal seal was defecting, 2heads were just beginning to leak at the head/cyl joint, could see where the joint was indenting into the head surface in a small area.....hence poor sealing, thereby leaking. Suspect air leakage into inlet tube at the joint chamber of the carby.....those 4 inlet tubes carby to engine. ) Combustion chambers indicated lean mix even the 2 good chambers, so upgrade carby jets to current specs. Overall, she was good, yea I,m looking forward to some really big trips, the 160 is really comfy, great endurance, strong, has proven to me it handles those "ugly times" just great. After sales service......excellent. Yes......I love me 160. 1 1
Oscar Posted January 14, 2014 Posted January 14, 2014 At around 350hrs I noticed a softness in 2 cyls, especially when cold, but improved a lot when hot, but still soft. Performance was a tad down generally.I,m glad we have done this exercise, couple of minor defects showed up as well, ( oil seepage underside 1mag ....internal seal was defecting, 2heads were just beginning to leak at the head/cyl joint, could see where the joint was indenting into the head surface in a small area.....hence poor sealing, thereby leaking. Suspect air leakage into inlet tube at the joint chamber of the carby.....those 4 inlet tubes carby to engine. ) Combustion chambers indicated lean mix even the 2 good chambers, so upgrade carby jets to current specs. Overall, she was good, yea I,m looking forward to some really big trips, the 160 is really comfy, great endurance, strong, has proven to me it handles those "ugly times" just great. After sales service......excellent. Yes......I love me 160. Russ, I don't want to be alarmist here, but if you have obvious evidence of lean running then it's possible you've been running at least some cylinders overtemp (if you have chts on all cylinders, then you will obviously know about that) and just maybe some detonation. Either will have potentially serious consequences for a Jab. motor down the line and it'd be a damn shame for you to do the work and not get a decent life out of the thing afterwards. Can I suggest that, if you can afford the time, contacting CAMit to see if it's worth sending your heads there for inspection, measuring and if they are ok, installing the inhibitor mod? CAMit has a laser-measuring machine that checks all over the heads so if there's any warpage it'll show up, (I think). If 'twere me, I'd get the valve guides (especially the exhaust valve guides) checked and possibly replaced and seriously consider throwing in the new CAMit rocker gear, it's a really nice upgrade. A chat to Ian Bent is really worth it, he can give you the full information about what to be wary of with Jab. engines that may have gotten too hot, right down to potential case-sealing issues, and he absolutely knows the 'chain of circumstances' that can happen to a Jab. engine from use. As with all close-tolerance 'systems', a problem that is apparently isolated to one area of that 'system' can have what might be called 'collateral effects', and Ian and his people know every one of them. On the theory that forewarned is forearmed and that the time to discover you've not noticed some other 'downstream' problem is not when you've a vast way out in the boonies where even a relatively minor issue could be way more expensive than when it's found at home, I'd reckon that 20 minutes on the phone is cheap insurance. 1
Oscar Posted January 14, 2014 Posted January 14, 2014 Amendment! Just recognised your 160 is 24-reg, so CAMit mods are not allowable, which is a real pity. Unless it's a C model, which means that a Part 21M aero-engineer could sign them off, but your timing is probably just too soon for the CAMit mods to have the test results in to the satisfaction of any Part 21M engineer to sign them off, other than the select few who actually have worked with CAMit. FWIW, our little ST1 rebuild includes a partial CAMit-upgraded engine and as a 55-reg aircraft we can have those mods signed off by a Part 21M engineer and we have the luxury of access to two who know Jabirus, Jabiru engines and CAMit's mods in great depth. We rebuilt our engine at CAMit but held off on the 'new' CAMit-improved heads until they have the requisite ticks of approval, which are in progress. Our strategy is to fly, with due attention to CHTs, on the old (thick-finned! ) heads until we can easily move to the new heads, so it'd be a fair representation to say we are using a 'half--way house' approach and realising the 'capital' we have in our current heads. Yes, we recognise that we have to fly with strict attention to CHTs etc. and we'll be installing CHT and EGT probes on all cylinders to ensure that happens. We have decided that it's more cost-effective to put a couple of hundred hours on our 'old' heads with careful flying, to be able to later bolt-on CAMit's improved heads when they have the necessary ticks of approval. We aren't even considering the possibility of transplanting to the 'Chinese' engine later on, because we believe - on the evidence of having damn well seen and talked through the CAMit developments with the man who is developing them - they are simply a better option. We do have some reason to sustain our belief in this, but that won't be confirmed until the release version of the 'Chinese' engine is available for inspection. That is rumored to be quite soon now. Bottom line: if I were in your position, I'd firstly: contact CAMit and discuss the engine, and secondly: decide what is the best economic path for your engine work. Just a refurbish of your engine, if it isn't seriously compromised, may give you a couple of years of flying reasonably cheaply while you can await the real-time results of CAMit's developments vs purchasing a new Jabiru 'Chinese' engine. A 160 is a very couth way of flying distance in Aus. conditions.
Dafydd Llewellyn Posted January 14, 2014 Posted January 14, 2014 Russ, generally the aviation scene doesn't get into this stuff. If you add an oil to the fuel it must not lower the octane rating for one thing. Ordinary engine oil will so if you had an engine consuming a lot of oil even if only on one cylinder it could cause it to fail through preignition/detonation effects.IF I was running a Jabiru engine I would add a very small amount of a good additive that won't make the fuel go stale quicker or affect the octane rating. (about an egg cup to each tank of racing outboard). But you didn't hear it from me. It mixes well with avgas or mogas and gives a bit of assistance in preventing cylinder corrosion. Nev One thing people tend to overlook, is that adding oil to your fuel alters (increases) its viscosity - which makes it go a little slower through the carbie jet, needle etc - which thus has a leaning effect on the mixture. So if you're planning to try this, make sure you have a full set of EGT probes and watch the before and after effect carefully, or you might just do more harm than good. 1
M61A1 Posted January 14, 2014 Posted January 14, 2014 I don't know where you would stand with a Jab, but I have used Moreys upper cylinder lube with what I think are good results on many aircooled four stroke motorcycle engines (one of those in a 95.10). Despite running slightly rich, I've had the valve train on my old Gixxer, take 150,000k's of absolute flogging, showing little wear and always clean with no build up. You use about 40mls per 6ol so it's not going to really alter the fuel viscosity significantly like adding extra 2-stroke oil will.
facthunter Posted January 14, 2014 Posted January 14, 2014 At the rate I'm suggesting, this factor would not be of any significance. In fact I doubt if it would be detectable.. Your point is relevant with higher mixing ratios/concentrations of thicker oils of course. in the area where two strokes operate. 30: 1 etc. If you were going to add oil to fuel and remove a pump as in a 582 where this can be a choice for you. It is certainly a factor. Nev
Russ Posted January 15, 2014 Author Posted January 15, 2014 Ok....the engine is now back together, fired up beautifully, did the required ground run ups, then took to the air and the required air stuff was done. She,s singing like a canary, temps and all that......perfect. Friend, long time pilot, on board with lame, says sweet as. I,m a happy chapy, pity about the weather tho, winds/rain etc looks like it,s set in for some time. Oscar......yes have touched base with Ian, it,s now the "waiting game" re his engine, let,s see.
Downunder Posted January 15, 2014 Posted January 15, 2014 At around 350hrs I noticed a softness in 2 cyls, especially when cold, but improved a lot when hot, but still soft. Performance was a tad down generally.I,m glad we have done this exercise, couple of minor defects showed up as well, ( oil seepage underside 1mag ....internal seal was defecting, 2heads were just beginning to leak at the head/cyl joint, could see where the joint was indenting into the head surface in a small area.....hence poor sealing, thereby leaking. Suspect air leakage into inlet tube at the joint chamber of the carby.....those 4 inlet tubes carby to engine. ) Combustion chambers indicated lean mix even the 2 good chambers, so upgrade carby jets to current specs. Overall, she was good, yea I,m looking forward to some really big trips, the 160 is really comfy, great endurance, strong, has proven to me it handles those "ugly times" just great. After sales service......excellent. Yes......I love me 160. Good stuff Russ.....Hope my 912 lasts to 350 hrs before needing major work too....
Oscar Posted January 15, 2014 Posted January 15, 2014 Ok....the engine is now back together, fired up beautifully, did the required ground run ups, then took to the air and the required air stuff was done.She,s singing like a canary, temps and all that......perfect. Friend, long time pilot, on board with lame, says sweet as. I,m a happy chapy, pity about the weather tho, winds/rain etc looks like it,s set in for some time. Oscar......yes have touched base with Ian, it,s now the "waiting game" re his engine, let,s see. Russ - sounds good!. Hope the 'touch base' with Ian was productive; he's the most knowledgeable and the straightest shooter I've ever come across re Jab. engines and the amount of work he puts into researching the problems is amazing. He kept a watchful eye over us when we were rebuilding our engine at his place and we asked every dumb question re how things worked you could imagine (plus made and then recitifed many dumb rookie-Jab-engine-builder's mistakes, as the guys there set our feet on the right path), and he didn't just say 'do it this way', but took us off to his computer many times and showed us the drawings, FE analysis etc. and explained the whole 'effect chain' of mods. He doesn't throw a band-aid at a problem but chases every rabbit down every burrow and everything he tries, he personally flies first in his J230 before anybody else gets to use them. He's an aerobatics nut so you can petty much assume that he gives them a decent workout, too.
Russ Posted January 15, 2014 Author Posted January 15, 2014 Good stuff Russ.....Hope my 912 lasts to 350 hrs before needing major work too.... No mate, not major.......just a tweak here n there. (Spose I could bolt in a brand spanker every 600hrs, that would give me close to 2000hrs, equivalent to a Rotax 4banger TBO .....even cost wise ) Seriously tho......said it before, jab blundered yrs back by not making the Rotax an option to buyers, the jab would have been a world beater. .....however......folks like CAMit, just might get the package right, I actually think they will. 2
alf jessup Posted January 15, 2014 Posted January 15, 2014 Good stuff Russ.....Hope my 912 lasts to 350 hrs before needing major work too.... Hey Downunder, I would be disappointed if your 912 doesn't get to 2350 hrs before needing major work. Alf
facthunter Posted January 15, 2014 Posted January 15, 2014 The basic engine of a Rotax 912 can usually be left alone. It's the rubber fittings, inlet and cooling system and exhausts that have to be looked at and the drive should be retensioned internally as specified.. I don't regard any aero engine as fit and forget. Where you have vibration you will get cracks and deterioration. I don't expect a Jabiru to go beyond 500 hours without a top. Some will and that is fine if it is checked. That's a fair bit of flying and plenty of motors need the same type of servicing. None of the parts are very expensive and I would replace the exhaust valves then regardless of what else was needed. Anyone spannering the motor should be genuinely familiar with them and a careful person. I've had plenty of stuff left loose in situations where there is no way it should have happened by fully qualified people. The more work done the more the chance of something left wrong. This often happens with cars and seems to mitigate against having things worked on. Nev
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