Gas smell in oil

[c4550]

For my fellow v-rodders. I had a small miss that got worse over 100 miles until one day it barely ran. Got it back from the shop today. The repair shows "malfunctioning hose clamp on high pressure hose. replace clamp. change oil to remove contaminants." dealer says all good now. I'll keep the forum posted if i notice any other problems, ex. oil consumption. either from running lean due to the leak, or damage from diluted oil. I'm hoping all is well I recall a post (not sure if it was on this forum or not) where someone else had gas in the oil. I still can't figure out why a hose leak would go into the crankcase ond not leak on the ground. Safe riding all!


Frank
66 XLCH
03 VRSCA

[c4550]

So far seems all is well. Too early to really know yet. But no oil usage. No gas smell in oil yet. But i've only rode about 150 miles since it returned. Still has that minor, but irritating, miss at 2900 rpm. but from what i understand that;s normal and will be correectd with a power commander.

[ksa v-rod]

missing at 2900 rpm not normal and would doubt that the power commander would fix it. i think you need to get your dealer back on the job to diagnose the problem.

steve

[johnf95111]

I changed my oil at 6k miles (after a run to the Sturgis ralley) and it had a fuel smell.

This got me thinking, hmmmm. How in the h3ll does fuel get in the oil????

The only think I could come up with was via the oil breather tube. I've noticed when I fuel up and top-off up to the lip of where the cap goes, the level will slowly recede back down to a lower level. I did a test at the pump and topped it off several times only to have it recede back down the same level. I looked for overflow dripping from below, but there wasn't any. Hmmmm????

The overflow must go into the carbon evaporative system; one of those EPA things. I haven't looked yet, but I suspect the oil breather tube is routed there as well. This would provide a path for fuel into the oil system.

I'll update after further investigation.

Luego,

John F.

[c4550]

John,
Let me know what you find out. I was really confused by how that could happen. One thing though. Once my loose fuel fitting was replaced, no more gas smell in the oil. And I don't top my tank off when filling. I think you're on the right track but there may be more than one way that it happens. Regardless, I'm very interested in what you find out.

[VRodDrew]

Originally posted by johnf95111
I changed my oil at 6k miles (after a run to the Sturgis ralley) and it had a fuel smell.

This got me thinking, hmmmm. How in the h3ll does fuel get in the oil????

The only think I could come up with was via the oil breather tube.

The most likely way gasoline ends up in your oil is as a result of "incomplete combustion."

Think about it this way - with every combustion cycle of the engine a mixture of gasoline and air are drawn into the combustion chamber at the top of the cyclinder. As this mixture is compressed, and the piston nears the top of its stroke, the spark plug fires and the piston is propelled downwards, thus powering the engine.

The ignition of the gas and air mixture is neither instantaneous, nor is it 100%. After the sparkplug fires, it creates a "flame-front" that spreads throughout the combustion chamber, combining the oxygen in the air with the fuel molecules. This process takes a very small amount of time (we're talking fractions of milliseconds here...) Also, not ALL of the gasoline that has been drawn into the combustion chamber will be burned - and a tremendous amount of engineering research has gone into reducing the amount of gas that is not combusted, because this is a prime source of tailpipe emissions. One place that gasoline can "hide" during the combustion process is in the small gap between the piston rings and the top of the piston. Fuel that gets caught here will be shielded from the "flame front" and as a result may not completely burn up. Thanks to improved metalurgy and other engineering advances, they have been able to shrink the gap from the top of the piston ring to the top of the piston considerably, especially compared to engines of 20-30 years ago - but there is still a gap, and some gas still remain unburned. Gas that is not consumed in the combustion process will seep down, past the rings, and into the crankcase, where it ends up in the oil system.

Also, any engine cycle where the sparkplug misfires, there is likely to be unburned fuel condensing on the cylinder walls and slipping past the piston rings. Most of the unburned gas and air vapor will be blown out of the cylinder via the exhaust valves - it then heads off to the exhaust system where it can sometimes ignite and cause a backfire, But again, some gas will end up in the crankcase.

[johnf95111]

Hey Drew,
Thanks for the info. And have another question:
I've owned and worked on many vehicles ranging from the '60s to '03s and this is the first time I've experienced this phenomenon.

Why would I first notice this on the V-rod?

Thanks,
-j

[VRodDrew]

Originally posted by johnf95111
Why would I first notice this on the V-rod?

Probably because, like me, until you bought your V-Rod you didn't pay that much attention to the stuff that drained out of the engine.

Seriously, I don't think there is anything peculiar to the V-Rod's engine that would cause gasoline to mix in with the oil.

[johnf95111]

I have a Porsche 928GT that likes to be run pretty hard. I am very interested in what comes out of its oil drain. I stick my fingers in it looking for stuff that shouldn't be there and look in the oil filter for chunks. I've never smelled gas.

When I did the V-Rod, the things that hit me were how thin the oil was and the strong smell of gas.

Hmmm. I'm leaning to a V-Rod specific problem.

Thanks,
-j

[VRodDrew]

Take it to a dealership and have them look at it.

[johnf95111]

I'll dig into it a bit myself first. That way I can point to the problem.

I've found the dealerships don't really know squat about the V-rod yet.

Thanks,
-j

[Polizzio]

I have to agree with you guys, I've been changing oil for 29 years, my cars, my motorcycles, and I just did my vrod oil and filter for the first time myself, strong odor of gasoline. Nothing I've replaced before smelled so strong of gas, but I doubt it will hurt anything. I got a lot of faith in Porsche designers, and she is swimming in Amzoil syn now.

[johnf95111]

I'm now runngin AMSOIL as well. I still need to hunt this one down.

I'm concerned about the effect this will have on the longevity of the engine. It may cause increased seepage at the gaskets too.

If it wears prematurely, I can then get the big-bore kit. Hmmm.

-j

[c4550]

Another thing to consider about the unburned fuel thing. My loose fitting was causing it to run LEAN not rich. If anything I should have had less gas in my oil from the loss of fuel pressure. With the faulty fitting I never smelled gas nor saw any drip, until i pulled the dipstick.

[VRodDrew]

In Imperial China, there used to be a whole team of monks and priests who would faithfully examine (sometimes even taste..) the contents of the Emperor's chamber pot in an effort to predict how their revered leader's health, moods, and fortunes would fare in the days ahead. I suppose there was a smidgen of scientific value in examining this stuff - but for the most part it was probably just a waste of time.

If you are really concerned about the gas in oil thing - then I guess I've got two suggestions:

First, at your next oil change, save the entire container of old oil, and send it off to a chemical lab for analysis. They will be able to determine what fraction is unburned gasoline, what is used motor oil, how much might be water, and how much is metal fragments. If it is an automotive testing lab, they will also be able to tell you how this compares with other vehicles. I can certainly assure you that during the extensive testing program the Revolution engine went through, they saved and analyzed just about every drop of oil that came out of the test engines. (There was a large sticker on the side of the test bike they had at the Art Museum in Milwaukee mandating that all oil was to be retained for testing.) If they had discovered something that would cause a problem - I am pretty sure they would have made corrections before they went into full production.

Secondly, you could request that the dealership do a series of compression and leakdown tests on the engine. This will establish if there is a problem with the rings or valves. If there isn't; and you still have a strong gasoline smell, then I would suggest that either it is nothing to worry about, or that somehow your data is being compromised.