engine oil

[J.j.]

Hi guys,
I\'ve been told that it\'s actually better to use full synthetic over mineral oil on FDs.  Due to the fact that it\'s a turbo car and it runs very hot.  
Just wondering why is it that Mazda started telling everyone not to use synthetic in the first place.

Cheers

[g11ary]

because 30-25 years ago when rotarys were still quite new , double ester oils and the technol was not there. The synthetics then were not very good.

[J.j.]

That makes sense.  
So, apart from RP, is there any good alternative??  Mobil 1??

[clive]

Hi JJ,

Yes there are some synthetics out there that are compatable with Rotarys but also a lot that won\'t be !

Garry is right about oils becomeing more advanced but l cant help but think back every time l see these posts that in my FD hand book it says
" do not use synthetic motor oil"

It worrys me a little that people will start putting synthetics in Rotarys that are not designed for Rotarys and break the seal between the tips and the Rotor walls leading to loss of compression!

It is much more important to worry about regular oil changes at 3,000 miles than messing around with oil but that is just my opinion.


I personaly have run just good quality mineral oil in my high horsepower engines and never had a problem, indeed as far as l know Rotarys don\'t suffer from oiling problems in other words

                  "if it ain\'t broke don\'t fix it !"

[J.j.]

Thanks for that Clive.  
Just thought that it might do my engine and turbos good.  Help them last a bit longer.
Where can I find out which ones are compatable with rotary and ones not??

Cheers

[zevans]

Search for "oilman" posts on here - he knows his stuff and there was a thread he started where we did this to death!

[g11ary]

I have had a conversation today with Royal Purple, and have a in depth meeting with him next week.
He says that the as I quoted oil has moved a lomg way since Mazda started to produce rotarys.
Rotor tips are either steel or ceramic and will not be damaged by the oil, the rubber seals that are in the engine will be better protected and double ester oils wil keep soft and supple, where as mineral will make hard and brittle over time, one of the causes for engine rebuilds is oil seal failure, if you have a didggy oil seal that is crudded up then by cleaning the seal you may make it leak, but if its that bad its running on borrowed time anyway and was due a rebuild.
Old lotus used to be notorious for leaking but now some of the old lutus club and race guys are using it they have stopped leaking, mineral was just buggering the seals.
It is important to remember that when changing you oil only approx 5 ltrs get drained, where as on a fd it holds approx 7ltrs, so if not fully drained you will get some crud washed back into the clean oil, that applys whether syn or mineral, if you mix the 2 oils RP synthetic is good enough for it to be still more than capable of protecting you engine, where the mineral will be survirly deteriorate within the first 100 miles because of the crud washed back in and not being good enough to protect.
I will have writen testermonials next week from race teams that haved raced a season, stripped the engines and simply rebuild without replacing all the usual parts they would have if still running mineral, Syn runs so much cleaner and does not break down as quickly. Austin Healeys have been racing on RP for a couple of seasons and report clean oil when changing.

John Helps has been running RP for 2 years now and he must have one of the oldest engines, still running and on a single turbo, gt35. How many other RX7\'s out there still running that mileage on big singles. To me says lots. I believe he has had it compression tested and still seems to have plenty of life.
I guess oil is a bit like our diets, if you look after your engines they will last that much longer, although its no good chucking in a lettice if youve been eating bugers all your life, it needs to be for the life of your engine not just a treat.

Will come back on this thread next week once Ive learnt more and will post reports, testermonials and specs if people are interested.

[brian snapes]

Useto own a cateram 7 with full blown coswoth BDR, ran it on mineral oil then changed to synthetic water temp rose by 5 degrees, because the viscosity of the oil held temperature longer, do you want to run at possible higher temperatures?

[g11ary]

What oil, as some synthetics are not truely what they say they are, royal purple claim cooler running temps, but I will ask this at my meeting .

[Steve Burnett]

Im very interested in whats going on here, I\'ll be changing to RP I think after the next oil change. I was using Castrol mineral but its now got "anti wear" additives in it, and I don\'t want them in it!

[g11ary]

Next week should be very interesting and a big learning curve for me, I may also be learning about the oil testing fascility and will have use of a portable machine, I am still waiting for the long awaited syphons and containers, but if a couple of you want, send a small sample of your oil to me and make no promises but will see if he will let me analise them, could be interesting.
Run the car to warm and take sample, dont want the first drop if you remove the sump nut as first gush would be full of crap settled and bottom nor last, just remove and after 1-2 secs get sample.

[oilman]

OK, indeed I covered this extensively before but the big question is what do you mean by synthetic?

http://www.mazdarotaryclub.com/forums/showthread.php?s=&threadid=10025

You see esters swell seals and pao\'s shrink seals (we\'re talking true synthetics here not petroleum oils) so they in the right balance can be fine.

Most oils out there today labelled synthetic are not, they are highly refined mineral oils (hydrocracked) and are perfectly suitable. The contents of the can is important!

Is a semi-synthetic (petroleum) oil suitable - YES

Is it better than a mineral oil - YES

Do I need to change every 3000 miles with a semi - NO

Are synthetics better in a Rotary engine - YES

Does Mazda recommend them - NO

Does Mazda define what they mean by synthetic - NO

These are just some of the Q&A\'s however a synthetic oil was developed in the states for the Rotary - you may find this an interesting read!

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=005535#000000

At the end of the day, it\'s your choice. The chemists say NO PROBLEM and they\'re probably right as I\'ve not had any conclusive proof that a synthetic oil caused a rotary engine failure.

Unless of course you know otherwise...................

Cheers
Simon