oh yeah...Valvoline 10W-30 or Castrol GTX 10W-30.

(Isn't 10W-40 like...forbidden?)

 

lol...exactly

10w-30 in these engines is insane if you ask me, especially with proven 3+% fuel dilution after a mere 1,000 MILES!

 

I run 10W-30 in the winter and 20W-50 in the summer, when the car is driven a lot more.

Question: While it is known that there is fuel dilution, what offset is there by the addition of the quart of oil the engine 'uses' every thousand miles or so? Or is that oil dilution figure taking this into account?

 

hmmm why dont more people use 15w-40.?
its between 10w-30 and 10w-50.
and it must contain less additives then a 10w-50. and may be more resistant to fuel dilution.
Its been awile since i did my reading on oil (so im sorry if im way off the mark ), but im pretty sure the further the two numbers are apart - the more the oil thinkness /viscosity changes as heat changes and the more additives the oil must have to achieve these different thicknesses at different temps. i.e. 15w is thinkness at cold temp and 40 is thinkness at operating temp.
The less change the oil has to go through the better, and the less additives are in the oil.
Its not practicle to have a single weight oil (especially in our cars) as it would not be able to protect our engines at both startup and operational temperatures as different viscosities are required for these tasks.
It needs to be thin enough to circulate and lubricate the apex seals etc at startup but be resistant enough to heat that it dosent break down and stop working correctly at the higher operating temps of a rotary.

 

this a reason not to use 10w30 if this oil was ran for even 2000 miles it wouild have been horrible UOA.

Also after reviewing some more of that info the schaeffers viscosity a higher temps is in fact on par with idemitsu if not greater. That is really odd considering it has a lower viscosity index. I think i know what im going to try although i was using Schaeffers 5w20 in my mazda 6 before an accident

 

Because 20w-50's better. Better body and viscosity...

 

20w50 Amsoil and Atkins filter every 1500 miles, 1oz.Amsoil HP Injector 2 stroke/gal. of fuel in the tank.

 

I'm currently running Mobil1 or K&N filters, how much is the Atkins?

 

sre you running 20w50???

 

No, I'm currently running Mobil 1 EP 15w-50. Amsoil 20w-50 is going in after another 2,000 miles on the Mobil 1.

 

10w-30 since I mainly just drive around the street. If I was racing I would run 50.
I pick 10w-30 for street use because I'd rather not trash my bearings waiting for oil pressure to build up during cold starts.

I'm not a fan of wide spread weights like 10w-50, those are more prone to degradation from my understanding.

 

Just drive it easy for 5-10 minutes until it's warmed up, that's what I do.

In an FD, I have to believe 10w-30, with the fuel dilution, shears down to a 20 weight very quickly. UOAs would show this; you 10w-30 guys need to get your oil analyzed ASAP, I have a feeling you'll be unpleasantly surprised by the results.

 

Theres alot of people who ran 10w-30 for years without a problem.

To add to that, rotary engines fail prematurely from improper use/build/age, overheating or detonation.

I dont even think theres any recent history of an engine failing due to wrong weight of oil, or any oil related problem.

 

This is a very interesting thread so far. So the reason why you guys are running 20-50w is due to fuel dilution causing the wieght of the oil to decrease?

 

wrong....if you read the whole thread, I already posted that Brain (BNR turbos) had an oil related failure...he specifically cited the reason as waiting too long between oil changes

 

+1

 

Im not sure how this in any way relates to a cold start while waiting for oil pressure to build up.
I change my oil in very frequent intervals, plus my oil pan leak keeps me constantly putting in fresh oil, lol.

 

<----- Valvoline Racing VR1 20w-50 all year round

 

i was recommended to use "the cheapest 10w40" by RR&R i trusted them and used always used SupreTech (yeah, the wal-mart stuff) 10w40 SM with regular changes @ 2000mile intervals. no problems at all

 

That pretty much is 180 degrees from all that I've learned over the years from speaking to rotary gurus.....I'd be curious to see your internals upon teardown.

I run Idemitu 10w30 in the winter months here in NJ, and idemitsu 20w50 all other months. When I lived in Texas I ran 20w50 year round. You just have to make sure to warm the car up a bit and drive her easy until she's up to operating temp

 

Nobody here seems concerned about a 10w vs 20w during a cold start?

 

I'm more concerned about bearing wear at 8000+ rpms then at 800 rpm personally

 

if i still had the car, i'd gladly give you the block when rebuild time comes, but i sold it

we live in CA dude, we don't have to worry about cold start viscosity. a majority of 7 owners that live where it snows usually don't drive their cars in winter.

 

What was the waited time frame? That also makes a difference.

I wouldnt recommend anyone NOT changing their oil when 4-5 months go by.

And that was like what? 1 case? vs 2387238728372873872 other non oil related engine failures.

I dont see how this could be a big concern when you look at the statistics. Just change your oil religiously and you should be fine.

 

amen to that