What is the best Oil to use in a Rotary Engine?

[chc]

There appears to be some debate as to which type of Oil is best for a rotary engine.
In previous engines I have always used a top brand - mainly C*****l GTX (without advertising) with contraversy about D*****s veg oil and found both types as good as the other. The most important aspect I have found is constant regular changes no matter what sort of miles i was doing - considering I used to travel between 10K - 18K ech year I'd change every 3K to be sure.

However here we have the Rotary Engine which likes to use a small amount of oil too. I am adviced that it's best to use a Fully Synthetic Diesel oil - diesel as it has the additive to remove the carboning factor on the tips.
My query is with this particular grade, as it is extremely thin, surely this might be detrimental to the engine - any thoughts guys?
Ta
Cliff

[myatt1972]

Diesel oil?
A good quality mineral oil with frequent changes for me.
Also some 2 stroke oil with the fuel to help prevent engine wear.
2 stroke oil has lubricating qualities even after it has burned so im told.

[codge]

And again as Keith.

Diesel engine oil sounds like a recipe for disaster.

[Johnnyboy]

There has been a lot of discussion on RX8 forums about Synthetic oil and its part in RX8 engine failures. I will try to find a link, but to give you the headline there were some heavy duty guys saying that Mazda only recommend Mineral Oil, specifically NOT to use Synthetic.

This was interesting, as I have always used top grade synthetics in Miss January.

Everyone agrees that synthetics are better lubricants. The argument is however that when synthetics burn (not a problem in piston engines or rotaries running pre-mix) they leave residues which build up around the corners of the rotor tips and this has been cited as one of the causes of premature engine failure in RX8's.

With Semi-Synthetics it is down to the definition of "semi". As I understand it there are no standards for semi synthetic construction, so good Semi's have more synthetic (making them bad for us....) while cheap semi's are mostly mineral oil (and therefore less bad for us....).

Also, when Tim at RX Motors replaced the tips on Miss January a few years ago he told me to use Mineral, and he knows an awful lot....

So this would imply you should either use a mineral oil or (best) take the OMP off, use synthetic in the sump and mineral (or maybe 2 stroke oil?) in the pre-mix,

john

[codge]

Strikes me best of all worlds is to use mineral in the sump, changing every 3000 or so (filter every other change), and back that up with Millers KB2T as a weaker premix whilst keeping the OMP in service.

By weaker premix I use 250:1, that's 80ml into 20litres of fuel. Hasn't got to be exact since the premix is only a back-up.

I say 'best of all worlds' 'cos it's as cheap as chips doing this; OK, a 5litre Millers costs around £45 but that's years and years of motoring for me.

I think the above regime is right for engine longevity.

[ian65]

Diesel oil?
A good quality mineral oil with frequent changes for me.
Also some 2 stroke oil with the fuel to help prevent engine wear.
2 stroke oil has lubricating qualities even after it has burned so im told.

agree with this 100%.... mineral and 2 stroke premix all the way!

[chc]

Well it all sounds good to me too - so I'll stay with the mineral & premix and that's why its' 'GOOD TO TALK'
Ta
Cliff

[kenwhiteside]

Hello,

Wanting some recommendations for oil for my Elford. Now reading around the net I have come to the decision that I want to run mineral oil with regular changes as opposed to a synthetic rotary specific oil or a synthetic / pre-mix situation.

Now the 84 technical data states a whole range of oils for different temps from 20W-50 to 5W20. As I live in England and drive my car in the winter looking at the guide its looking like 10W-40 is the go but happy with anything recommended really.

So can someone recommend me an oil (ideally also with were to get it from). I can get trade at Halfords but not sure anything they have is suitable. Looking for a cost effective oil as aforementioned I plan on changing it pretty regularly.

Cheers

Tim

[TOOL]

Castrol GT-X has been recommended for rotaries since day dot.

Oils have changed though and it is now semi synthetic. I run it and it's fine. £14 delivered off eBay and I get through a fair bit with the OMp turned up. I don't get any smoke or oil smells but I also don't need to do oil changes if you know what I mean

[kenwhiteside]

Castrol would be my usual having run gtx magnatec in my subaru turbo for years. GTX is part synthetic though? Do you run 10w40?