hello all!

while changing the oil this eve, i realized i only had 3 qts of 10w30, but a case of 5w30.
Unfortunately, i realized this after i added those 3 10w30 qts. any issues with mixing the weight, and using 1 qt of the 5w30.
I did a search on the forum and came up emty.
thanks in advance
eric

 

Shouldn't be a problem.

 

but isn't 5w30 a little too thin for the 13B??? Just my reasoning since so many others seem to use 20w50

 

Don't see too many FDs croaking do to oil related failures. I run 10w-30 in mine. 5w-30 on a street driven car shouldn't be a problem.

 

My comments on oil weights are in here:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/going-synthetic-quick-questions-synthetic-guys-411254/

You can read and decide for yourself.

 

No, in fact the only two grades recommended in the owner's manual are 5w-30 (for low temperature environments) and 10w-30 for everything down to about 0 degrees F. You should have no problems with the little bit of mixing you did.

 

fuel dilution and blowby rapidly degrades oil in these cars...the same guys who wrote the FSM prob also designed the AST

my next mission after I get the car back on the road is to do a lab viscosity analysis after 2,000 hard street miles on 15w-50 Mobil 1 and put this issue to bed

 

Just search for Turbojeff, he's already done it sport.

 

got a link?

 

A quote:

 

yeah I knew that (10% fuel dilution)

I wanted to see viscosity analysis results....I'm pretty sure Amsoil will do this testing for cheap

 

Ok, but what is your expected results? I guess the question is, what are you trying to prove?

 

that there is significant viscosity loss after 2,000 miles, relative to new oil of the same grade and brand name

when I say "significant" I mean 10-20% or more

edit: ASTM D-445 and D-4683, as defined here
http://www.performanceoiltechnology....anttesting.htm

 

So are you hoping to prove that running a heavier weight is beneficial as it will last longer between scheduled maintenance?

 

"last longer" is subjective I suppose

let's say "maintain acceptable viscosity"....also subjective...bottom line is I would like to show that turbocharged rotary engines are brutal on motor oil, compared to a high performance piston engine

 

I don't think there is any question about that (which is why people here change their oil more often than say BMW owners). The question however is about what weight people should be running on the street, not necessarily how fast will it break down.

For instance, running a heavier weight in conditions where it will never reach optimum temperature probably removes any benefits of it not shearing.

 

what is "optimum temperature"?

I've never heard of these engines having a problem running too cool

 

"When an oil is cold its viscosity increases, and it does not flow easily. If you use high-viscosity oil in low-temperature weather, heavily loaded engine parts will not receive oil until the engine warms and the oil thins. Hot oil, on the other hand, is thin and flows easily."


i.e. if the oil doesn't reach a good lubricating temperature, you are increasing the wear on your engine and other lubricated parts (not to mention the tough time the engine has pumping it through giving worse gas mileage).

 

true, but even in "cold" ambient conditions, these engines reach operating temps (i.e. 180 F) FAST...the amount of time spent at "low" temperature is very limited unless you drive the car 4 miles every day and park it (which is not me, I always drive the car hard, once warmed up, and for at least 30 minutes)

 

That depends on the car and the driving. I've driven to track events on cool days and never hit 180F on the highway. This is why for most of the people, 10w30 is best. It just doesn't make sense to add more wear on the engine unless they know they need the extra protection.

If they are going to be driving the car under conditions that make sense for something heavier, then it makes sense (ex. I run 20w50 for track days).

 

I thought the W in 10w-30 meant winter. Meaning that 20w-50 would flow 2x? slower then 10w-30 at winter tempetures and flow 2ishx? slower then 10w-30 at operational tempeture.

 

Yes, it is a viscosity rating and the W is for Winter. What YZF is trying to get at is that when oil begins to break down, it's viscosity changes. He's trying to prove that using a higher viscosity oil will last longer in a rotary engine since the amount it breaks down over time will still leave enough viscosity for it to be useful longer than a lighter viscosity oil (which is common sense).

However, given the fuel dillution problem of rotary engines, I still wouldn't recommend holding onto oil for too long regardless of the viscosity being used.

 

thanks for the input....i'll just let it be until my next change
(i'm on the 1000 mile or 3 months, whichever comes sooner plan)

 

2k miles is "too long"?

it wouldn't surprise me to see 10% fuel dilution within several hundred miles

these engines are seriously flawed in many ways, but they are fun

 

Hmmm, looking back in this thread, I never anything about a specific time frame as to what is "too long" (that was you who mentioned 2000 miles with your other account). IMO, that really depends on your driving. If you are tracking your car, you are going to change your oil more often than if you are daily driving.

Saying "change your oil at XXXX" isn't really the proper things to say, IMO, as whatever number you pick won't work for everyone.