ASH8

5. Better Cooling Fan set up...needs more air flow in hot (Summer) stop start driving.

ASH8

You don't use OEM cooling system or oil coolers or PCM.

Iluvrevs

That actually doesnt surprise me given that most ester based oils Ive seen have a HTHS number on part with 40wt mineral and PAO oils. Case in Point RL 5w30 has a HTHS of 3.8 which is the same as M1 0w40. Then RL 0w40 has a HTHS of 4.0 nearing mineral HTHS of 15w40 such as those from Vavloline which are at 4.2 or so if I remember right. All this while the 100C temp is within the usual for that grade.

RIP IT!

Looks about like every motor I have torn down where the oil wasn't changed regularly.

The wear marks on the rotor housing that are vertical and not horizontal are from lack of lubrication, which was more than likely caused from the extensive intervals between oil changes. If the oil has been changed around every 3K and the proper weight is used the scoring marks do not exist.

The cracking around the spark plug holes is from heat as mentioned earlier. Either too hot of a plug was used or the motor was ran warm for extended periods of time.

The main bearings will look like that every time when too thin of an oil is used. I recommend no less than a 10w-40 in all my motors.

All the rx8 rotors seem to have more carbon on them on the sides and combustion faces due to the side exhaust ports.

Neglect and too thin of oil is the failure for this motor. That about sums it up IMO.

9krpmrx8

iTrader: (46)

Those OCI's are crazy, I don't know why anyone would go that long without changing it.

Spirograph

I've been running Castrol 10w40 and Rotella 15w40 exclusively since I got my reman put in about 26k miles ago. I don't have an oil temp guage, so I have to guess when I've been driving long enough to get the oil temp up, but with the 15w40 I've been running lately I try to be gentle when I can.

I just last night picked up some Mobil1 0w40 with the idea that it provides better protection at cold revs, but I want to research some more before I install (I don't have a SOHN). I also picked up both Purple Ice wetter and DEi "Heater Hotter" which says it warms up your coolant 50% faster. Has anyone used this before? Is it safe, and is it safe to mix with wetter? ASH, what's your reason for staying away from 0 weight? Doesn't a full synthetic change on the cold end as it wears? Would I be better to use solely 0w40, stick solely with 15w40 diesel for the detergents, or would the two blend well together?

Can you explain further the asterisk that 5W30 Minimum is required, provided the OP upgrade has been done? Are you saying that 0 weight is okay if running stock r1 OP?

THanks.

jasonrxeight

well, if you are not racing the engine. there is no reason to use thicker oil than 5w30 really. if thicker is better then we would all be using molasses in our engines.
the debate between flow vs pressure is that yes you need pressure to get oil into the bearings but you also need flow to get the heat away from the bearing. 0W oil is not that great if the engine is not designed for it. the reason being it might be too thin at lower temperature to a point where there is too much pressure loss to get oil to where they are supposed to be. yet if you use 50 weight oil, its too thick for the bearings to have sufficient cooling effect.

al3k87

I only got around 5000km on my new engine and want to keep it healthy, I use mazda dexelia 5W30 and plan to change it every 3000km or year I also premix about 1dl every fill up to the gas tank. Ive heard people don't like the Dexelia Ultra 5w30 because of bearing failures or something, but is it really that bad?

Iluvrevs

No, its fine for that use. The bearing failures we've seen here are from abuse and neglect, maybe build error, if you look at bearing failure analysis tools.

poacherinthezoo

New/clean oil is the biggest factor (in my opinion, at the very least), and given your location 5W30 should be good. It may be worth researching if increase your oil pressure to series 2-ish levels will adequately address your concerns regarding bearing wear. You could extend that oil change interval to 4000 km without any significant risks, but it's worth reiterating that your standard oil change only replaces about half the oil in the engine.

Depending on what pre-mix you are using and how much gas you get per "fill up" you might want to consider going a tad heavier on the premix. 1 dL is about 3.5 US ounces, and I know with some premixes (e.g. Idemitsu) the manufacturer's recommend "dose" is 1/2 oz per gallon (i.e. 1.5 dL/38 liters). However, this is subject to extensive debate (a la the premix thread).

EDIT: I apologize if my metric conversion are a bit off - I gave it my best shot.