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glidernut

Motor Glider recommended 2 stroke oil?

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I have just purchased a Grob 103 c SL Motor Glider with a Rotax 505 engine and would like advice on the best 2 stroke oil to use. My 15 year old book indicates Castrol tts. Is this still the best oil?

 

 

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G'day G'nut.

 

 

 

I can't comment specifically about what to use with the 505, but someone here surely will.

 

 

 

However I can say that via historic 2-stroke motorcycle racing and thru Superkart racing which uses GP bike 2-stroke engines, the latest synthetic 2-stroke oils have been a revolution and a god-send, offering less plug fouling, less smoke, better lubrication for less wear and much, much less hot & cold seizing. In that game the top of the range synthetics by Motul are very popular (but also often with high-performance fuels) and that duty is much more extreme than a 505 in a glider.

 

 

 

FYI, I had a Schleicher ASW28-18 E a few years ago that was fitted with a SOLO sustainer engine, so have fun with your Grob 103.

 

 

 

Hope this is of some help, and welcome to the Forum.

 

 

 

Regards Geoff

 

 

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I've run Castrol Super TTS for years in a Robin 50hp 2-stroke.. never had any problems as long as the mix ratio is adhered too.. I'd keep using it.

 

 

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Thanks for the input Geoff.

 

I did find a reference from Pennzoil that explained why air cooled engines need a different oil than water cooled engines. However as you said oils have improved over the last 15 years. I look forward to additional input.

 

Thanks

 

Eric

 

 

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The aircooled oils are different. Ring land temperature is the critical factor. TCW3 is outboard and don't use it in any aircraft. Rotax recommend air cooled type oils in their liquid cooled engines. Penzoil ( Not Penrite) have tested and do recommend one of their oils, for aircraft use. Few companies do this, so it is a good indication of their concern. Don't know if it is available here in Australia. Synthetics used to be less recommended for aircraft where engines sit unused for extended periods . I have used Valvoline Racing Two stroke, and quite a few people I know use it. It's NOT a full synthetic Most of these engines do not put out the specific high horsepowers of the race bike engines, or anything like it but they do work quite hard and carbon build up in the ring grooves can fail the rings and you stop suddenly. Nev

 

 

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Thanks for the advice. I did read a test report from Pennzoil that indicated the "Pennzoil, 2 cycle, Air cooled oil with a category TC" is recommended for aircraft use.

 

Eric

 

 

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The motor is only running about 6,000 rpm I have had trouble with castrol TTS as the motor is not running hard enough to burn off all the carbon. The oil to be used is Castrol 2t

 

 

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The motor is only running about 6,000 rpm I have had trouble with castrol TTS as the motor is not running hard enough to burn off all the carbon. The oil to be used is Castrol 2t

The motor is only running about 6,000 rpm I have had trouble with castrol TTS as the motor is not running hard enough to burn off all the carbon. The oil to be used is Castrol 2t

The operating manual for the Grob calls for an engine speed of 6,200 - 6,400 rpm would this still be a problem? I will look for a supply of Castrol 2t. I am in Richmond Virginia and I cannot obtain Castrol 2 stroke oil locally so I will have to order on line anyway.

 

 

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Where does Amsoil fit in all this? The AMS bit, I understand, stands for "Alkyl Modified Silicone" - of which an example is Methyl Silicone - and this has considerably better high-temperature properties than straight mineral oil. The Rotax 505 that Bill Riley fitted to a Blanik in the 1980s ran 1:100 Amsoil - and the exhaust port was always wet with oil after a run. Bill switched to Amsoil in an attempt to reduce plug oiling in his inverted motor installation. It did some 250 hours without problem (apart from persistent plug oiling - but fine-wire platinum-point plugs are now readily available, and the CDI ignition systems have more power), as I recall, before being put back onto the PIK 20E from which it had been borrowed.

 

Amsoil produce a grade for outboard motors, so the stuff cannot be deficient in corrosion protection. That grade would seem appropriate for a liquid-cooled engine.

 

 

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My 15 year old book indicates Castrol tts.

My Mates and I raced vintage motocross for over 10 years, mostly 1970's MX bikes, important to you all were air cooled high performance 2 strokes and most of us over time tried all the various offerings and amongst us (talking a couple of hundred people here) Castrol TTS is one of the least liked of them all although some do like it in water cooled bikes.

 

Many of us considered that one of the cheapest, plainest 2 stroke oil out there was the best for our air cooled engines and that was "Mobil 2 Stroke Oil", not Mobil 1 2 stroke, not Mobil Racing 2T and not Mobil Outboard Plus (it can get confusing), just the bottom of the barrel plain stuff for chainsaws, lawnmowers and motorcycles, i.e specific to air cooled 2 strokes (blue in colour). It's smokeless, doesn't foul plugs and terrific anti-scuffing. Strip them down for their annual checks and can tell you low carbon deposits on piston and exhaust, those who used it were very happy with it. It's not synthetic and depending on engine size you run between 20:1 to 30:1, for yours i would think 25:1 would be appropriate.

 

1169900213_mobil2.jpg.2a3c890ea613b49e92a3a867f29bc337.jpg

 

 

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OK, Shell has withdrawn its "Aeroshell Sport Plus 2" oil, which was "specially formulated for Rotax 2-stroke engines" . That leaves the other oils that are listed in Rotax SI 2ST-008; or any super 2-stroke oil meeting ASTM standard API-ST.

 

Amsoil Saber is one that meets this standard. You don't HAVE to use it at 100:1

 

So, the experts on this thread have never tried it, and therefore do not know anything about it. How helpful.

 

 

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Hi Glider nut ,

 

The castrol is active 2T In Australia we all used to use s castrol super TT but it is not made any more here ,also Penrite hipper is good. Dont use motor cycle oils as they run different to aircraft motors.

 

 

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I have just purchased a Grob 103 c SL Motor Glider with a Rotax 505 engine and would like advice on the best 2 stroke oil to use. My 15 year old book indicates Castrol tts. Is this still the best oil?

The 505 is not a high performance engine and therefore does not require synthetics, castrol Active 2T is more than adequate, low ash good protection and long shelf life. Synthetics no matter what brand only provide protection against corrosion for 24 hrs after shutdown, where as the mineral based oils last for months.

 

Shelf life of premixed fuels also have short shelf life.

 

 

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Mineral based is probably more suitable. Pennzoil USA actually have a two stroke oil they RECOMMEND for use in AIRCRAFT. When there were a lot of two strokes around many schools used Valvoline racing two stroke which I have also used for years. Still mineral based. Mix all fuels as needed. Use in lawn mower what you don't use straight away. The outboard TCW3 is not recommended. (Generally) Nev

 

 

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As for oil congregating in inverted engines this problem is easily solved. Use an old set of plugs as minders and swap your good plugs when about to go flying. I had a 582 that was run on Penrite "green slime" for 300 hrs and the stuff accumulated in the ring lands and side of the piston on the exhaust side. Not pretty! Don

 

 

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Green slime was withdrawn from sale after a court case. It didn't mix easily either. I was never a user of it though a lot did. Most don't see the inside of motors and operator technique and particularly having the correct mixture is important with 2 strokes. so most just go on what they hear , which is somewhere between loyalty witchcraft and hope Nev

 

 

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