Ok, I know a fuel smell is common in engine oil for RX7s. I had it analyzed and it was 6% by volume fuel, which is too high (reduced 20W50 oil down to 5W30 equivalent). This happens within a 1000 miles on each oil change.

I change the primary injectors with new ones, and had secondary ones cleaned by Marren (no leakage in either). Had oil analyzed again and its the same; 6% volume!

Where is the fuel coming from?????

 

Sorry, I have a little bit of this problem too. I am interested to hear what others say. I think it could be side seals causing blow-by. How is your compression? Mine was @ 125 per face on both rotors. I was thinking about sending my injectors off. Where did you get the oil analysis?

 

I had this problem after premixing, and just change the oil more frequently. The best theory so far that I've heard is that the Viton oil control rings supplied with some of the rebuild kits that we use tend to aggravate the problem. And, of course, when the OEM seals get lots of miles on 'em.

A little "side" theory that I have is that side housing wear tends to add to the problem too. Makes sense to me, because my problems started with about 170,000 miles on her, and continue to this day 10K+ after the rebuild, 120 psi all faces (new rotor housings, all new seals/rings, but not new side housings).

I'm getting about 27 mpg, so it can't be due to inefficient combustion, lol...

 

Mine acts completely the same. It was a Mazda re-man about 50,000 miles ago.
{edit} I get around 23-25 mpg in mine. it's a S4 in a S5 car.

 

WYNE88N/A you get 27mpg wow......

Mine had some gas in the oil, so now i use thiker oil and change it more often.



Gil

 

6% by volume... holy chryst...

the side seals and oil rings are the main culprits.. however, i don't think its the viton rings...

I didn't have my housings lapped at 130K rebuild, but i DID fork over the 200+ dollars for a set of oil rings.. (not just the o-rings) and my oil is actually smelling nicer (if 20-50 ever smells nice at all).

I also have my system vented to atmoshpere through a catch can...

 

I Use 20w-50 and it does smell nicer than the 10w-30.


Gil

 

Yeah, but it's 95% highway miles, lol. My car lives at 75 mph, for the past 100K miles, at least...

Years- The more I think about it, the more I think it's the housings, not the side seals. My side seals are all new and flat, and the side housing wear on these things, as you know, doesn't exactly lend itself to "flatness", especially at the "football" ends. I'll bet that's where the blowby is occuring, at that .001 to .002" gap between the side seal and the worn housing area. And of course the compression pressures overtake the oil pressures on the other side of the oil control rings with ease, resulting in the "addition" to our oil supplies...

 

Yep I got the same problem. Wayne are you turbo or NA (could be a dump question but who knows). Reason I ask is cause I've heard this problem is especially prevalent in turbo cars that premix. Many people I know of have this same problem. I get about 1000 miles per oil change and then I'm about 3/16" above full. Weird thing is I get lower oil temps with this thinned out mixture--may be due to the increased volume, maybe the flow rate is higher since it's so thin, maybe both. And my housings were re-used with about 135k on them.

Scott

 

I'm NA, man (you didn't think my last name was "88N/A", did you, lol).

Yeah, I remember you talking about your problem, Scott- did you ever come to any conclusions?

You know, I figure on the bright side, our lubrication systems ought to be sparkling clean with all of that solvent in there, lol...

One of these days I'm going to rebuild again, and use new side housings, to see if my theory holds any water...

 

Ah, that explains it. I actually managed 30 MPG the one time I actually managed to stay around 75 for the whole trip. I usually end up with a little over 20 on the highway because I take back roads and average about 90
As for the oil in the gas, I agree thats its prob a combination of oil rings and worn housings. Either way, my rebuild helped the problem.

 

Oil Analyzers Inc did the oil analysis. Its less than $20 postage paid