Two Stroke Premix Suitable Oil For Rotax?

[BrendAn]

3 minutes ago, facthunter said:

Check the Crank Oils seals also if the Motor has been sitting or a long time since manufactured. Correct Mixture is critical.  Nev

I got given a high hr 582 once and when I filled the rotary valve bottle it ran straight into the crankcase requiring a new crankshaft..seals are part of assembly 

[facthunter]

Ther's the end ones too.. Nev

[jackc]

6 hours ago, BrendAn said:

Has it still got the oil injection jac

The 618 runs premix, same a the new factory 582 that I got. 

[BrendAn]

38 minutes ago, jackc said:

The 618 runs premix, same a the new factory 582 that I got. 

No worries.  Mine is oil injected ,I still put 200 ml in every 20 lt for insurance.  With amsoil there is no smoke. Clean exhaust and some people say they even gained rpm with it.

[jackc]

34 minutes ago, BrendAn said:

No worries.  Mine is oil injected ,I still put 200 ml in every 20 lt for insurance.  With amsoil there is no smoke. Clean exhaust and some people say they even gained rpm with it.

How clean do the spark plugs read? Do you run recommended heat grade, where is your IGN timing set? 

[BrendAn]

5 minutes ago, jackc said:

How clean do the spark plugs read? Do you run recommended heat grade, where is your IGN timing set? 

My plugs are clean but I use iridium plugs cross reference to the the stock plugs. Would not have a clue about timing.  I haven't touched it. Just clocked over 150 hrs . Runs very smooth . I imagine the timing would still be at factory settings. I wouldn't touch it unless there was a problem.  I like iridium plugs because they supposed to be kinder to CDI box's. I reckon they start better and run smoother with them.

[BrendAn]

Ignition timing is 15 degrees.

I have the 618 handbook here.

Can't see why you would have to touch it though.

[Methusala]

This topic was covered in some detail a few years ago. I think from memory Castrol 2T was the winner. Castro specialises in lubricating oils and most had good experience with it. Synthetic oils, people believed, had less persistence in maintaining a residual film between uses. FWIW. Just sayin'.Don 

[onetrack]

The performance of synthetic oils should be better than straight refinery oils, as the base oil in synthetic oils is chemically manufactured, which gives it better properties than straight refined oils, due to the ability in the synthetic manufacturing process to produce purer base molecular structures, with the most desired oil properties. 

 

Oil refined directly from crude comes with a range of chemical component structures that are not necessarily ideal for lube oil use, and the oil makeup has to be balanced by adding other additives to counter the undesirable chemicals.

Despite clever refining processes, the undesirable chemicals still slip through in the final base oil refinery product, because quite of number of the undesirable chemicals are either expensive to refine out, or have chemical properties that enable them to slip through hydrotreating.

 

The bottom line is all base oils have at least 7 extra additives added to them, to make them perform to the required level or oil standard. These additives are often quite different between the various manufacturers, and the type/selection of additives would more than likely play the biggest part in an oils performance.

 

The basic additives are;

 

Antioxidants to prevent oil breakdown by oxidisation

Acidity neutralisers 
Rust and corrosion inhibitors 
Viscosity index improvers (VIII's) to maintain oil thickness across a range of temperatures 
Anti-wear agents 
Detergents and dispersants to keep internal engine components clean 
Anti-foaming agents
Extreme pressure (EP) additives for heavy-duty applications 

 

The oil chemists have a huge array of chemical additives to choose from, all with different properties and performance - and they keep finding new additives all the time.

Plus, the chemists have to balance oil performance against their manufacturing costs, so if you want exotic, high performance additives, you have to pay.

 

In general, the oil film will drain off metal surfaces it's supposed to be protecting, within as little as 3 months, and chemicals in the oil either settle, react slowly with each other, or simply degrade by chemical bonding breakdown, over an extended period. Therefore, using fresh oil, and keeping surfaces coated with oil, are two of the most important things you can do, to prevent engine problems related to poor oil performance.

[facthunter]

SOME crudes are better than Others for Lube Oil. One good example is Pennsylvanian crude   Synthetic has many bases eg ESTER based. SOME synthetics way back didn't give much Protection from Oxidisation  in 2 strokes and were avoided. Today SOME/Most syn and Mineral oils will mix so you can get Part synthetic and the syn is made from LPG. Most crude has a Lot of sulphur which is highly corrosive when oxidised and the Mixed with water. It has ALMOST been eliminated from the Best Oi/fuel countries, LPG also has impurities but is removed during the  manufacturing process. Thickening oils is generally done by adding Polymers which are Plastic like Particles which have a finite Life in lube oils. It would be good if ALL engines were Pre-Pressurised with oil to reduce the damage of dry starts. Nev

[facthunter]

Castrol is "handled" by BP these days. Wakefield Castrol as we knew it is no more. 2T is an old spec for Lawn Mowers etc I would go for something better in an  Aircraft motor. A Rotax 618 is over 100 Hp/ Litre. My son Races with MOTOR EX as OK for Husqvarna/KTM. Nev