^ Agreed on the oil weight issue ^

My comments were ment as a word of caution when talking to the dealer.

 

Yeah, it's not going to turn out well if you take the car to the dealership complaining about fuel dilution and it turns out you're not using the recommended weight.

apagan01: If you get a chance to talk to one of your customers running the heavier weights in an X, could you point them to this thread? I'd be interested to see analysis results for a heavier weight since it appears tuning may not resolve the problem.

 

those customers change their oils every other race, very often, i havent seen one of them run their oils more than 2k,,,, i am not saying you guys have to do this,,, however thats the reason a lot of these guys dont stop by this thread because they will never see this oil fuel dilution problem because there oil never runs that long.

i never run more than 2200k on my oil,,, theres reasons for that

 

I like your style; a good idea for sure. I'm really interested how the results will pan out.

I just sent Oil Analyzers a sample of AMSOIL SS 0W-30 that was in the car for 3000 miles (to the mile ) on the stock tune. And part of me is wishing I'd saved a sample from my first oil change which had 4000 miles on it, with ~2000 miles of roadtrip/freeway commuting plus the break-in period.

 

You know at this point I think getting to see the %fuel in an engine running heavier than 5-30 with just 2300mi would be informative. Apa, are you running 10-40 or thereabouts and if, yes, would you consider looking at the %fuel dilution value on your next oil change? BTW the same request goes out to others that are also running heavier weighted oil.

Later, Ken

 

If they're race-prepped and changing the oil after every race, they're probably also not concerned about the additional wear the heavier oil is going to cause. That's my main concern is going to a higher weight on a daily-driver, and not something typically worried about on race-prepped cars.

Thanks for the update, though.

 

Putting in 10w40 still only works as a band-aide and not a solution. Although, it could be suggested for people who run their cars a little harder, it shouldn't be necessary on a brand new car.

35$ just in oil every 2,500 miles is not cool.

 

Got off the phone with Oil Doc and he says the engine was designed for the 5-30W oil and basically discourages the use of higher weight oils. So I am now more confused than ever; AMS says yes to higher weights, Oil Doc says no. Although in all fairness AMS did not say the lighter weight oil was THE cause of excessive fuel entry, rather he just suggested going to heavier weight oils.
I am not certain but fuel dilution existed for the 4G63T engine but not to the extent we have observed in the 4B11T engine. Since one major difference between these two engines is the aluminum block in the latter, I wonder if there are any differences in the time to reach operating temperatures for these two engines? If an alluminum head and block takes longer to warm up than one with only the head as aluminum, then this might be the reason for the higher %fuel in the 4B11T engine. Just something to think about before going to bed tonight!

Later, Ken

 

I just changed my oil on Saturday and today I went to check the dip stick and I smell gasoline. After that I started searching and I found someone that posted this for possible causes. I know some of these causes has been mentioned on previous posts but still it might help to strengthen the argument... But personally I think it might be the spark plug issue where it has fouled out due to the factory tune and thus now not being able to efficiently ignite all the fuel in the cyclinder....Here is the excerpt from someone on this issue...

"Many things can cause this, some are, from a short driving cycle that doesn't allow the engine to fully warm up, to a faulty fuel pressure regulator, to leaking fuel injector/s or a carburator float bowl being overfilled, to worn engine parts, like piston rings, valve guides, faulty spark plugs resulting in poor fuel burn ect, ect.

Basically it's gasoline getting from the top of the engine, into the bottom of the engine, where the oil sump is."

 

So I got my first oil sample today of my first 1,009 miles put on my EVO. Although the report shows dilution at 2.5% Robin (from Oil Analyzers), mentioned to me that this may be normal due to the fact that the engine was in it's break-in period. This was also the reasoning behind the copper and silicon contents being high.

I guess this is a good baseline for me. I will be sending out my sample of the 2nd 1,000 miles this weekend to both Oil Analyzers and Blackstone.

My Evo will remain stock at least until this dilution issue gets resolved or at least to where there is a more definitive fix.

BTW, we've all read in this post that our noses are subjective in indicating fuel in the oil, but I just turned 2,009 miles (1,000 miles on this 1st oil change), and it seems thinner (more diluted) and oil seems to reek more of fuel.

 

try this attachment:

 

Spreadsheet updated. theFLASH12's results have the highest per mile fuel dilution so far. As Oil Analyzers mentioned, it may be because of break-in, but I'd keep a close eye on it. Your results are all roughly equivalent to Q15H's 5k mile change (2.4k on the oil). Since they're all so close to his second change that had double the miles, I'd imagine your results are as indicated: Normal for the break-in period.

 

Ok, trying to obtain info. on causes for fuel dilution and persued the thoughts earlier regarding the use of aluminum.
Ever heard of piston slap? This occurs when a aluminum alloy piston immediately at startup, i.e., cold is significantly smaller than the cylinder within which it sits. At this time the piston's skirt apparently can hit and score the cyclinder wall creating a taping noise (not from lifters). I have read about this in Nissan's as well. Now because aluminum has twice the thermal expansion than steel, the X pistons when cold are potentially small enough to perhaps (because I do not know) to cause piston slap. Here is a quote(http://listserv.corvettemuseum.com/c...T=text%2Fplain) about the use of low silica pistons in forced induction engines: “The "2618" performance piston alloy has less than 2% Silicon and could be described as Hypo (under) eutectic. This alloy is capable of experiencing the most detonation and abuse while suffering the least amount of damage. Pistons made of this alloy are also typically made thicker and heavier because of their most common applications. Because of the higher than
normal temperatures these pistons experience in their usual application,
and also the low-Silicon content allowing the maximum possible Aluminum
heat-expansion, these pistons have their cylinders bored to a very loose
cold-fit. This leads to a condition known as "piston slap" which is when
the piston rocks in the cylinder, and it causes an audible tapping noise
that continues until the engine has warmed to operational temperatures.
These engines should not be revved when cold, or excessive scuffing can
occur."
Two points: I do not know if the 4B11 pistons are 2618 alloy (but probably something similar) and note the last sentence. Sound familiar? ... not about the scuffing but rather addition of fuel a la Mitsu TSB. So what we could have here in the 4B11 is high performance aluminum alloy pistons, which when cold, are allowing a lot of fuel through the cylinder walls into the engine oil, presumably more than Mitsu expected; I am assuming once warmed up, there is no/negliable fuel getting through.
If this is the case, the fix is not pretty!

Later, Ken

 

That i think would apply to iron blocks mostly.

The 4B11 is aluminum both the block and piston. So expansion and contration rate should be same, or very close.

 

Just to be clear here the original factory oil fill was changed at ~2440 miles with the results as posted. There has not yet been a second oil change. The odometer just now is hovering in the 4100 mile range.