 Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
My oil analysis has shown significant fuel dilution (3.5%) and requires action. I'm glad I got it analysed - not due for a change for another 5000kms. The lab suggested checking fuel lines, injectors, etc ( report here). Bike is 09 EFI. Oil is Mobil 1 Racing 4T and only done 2800kms on the oil and filter. The A/F runs between 12.7 and 13.7. A little research online suggested it may be due to the bike only doing frequent short trips. It's my commute vehicle and does 15kms twice a day (quite aggressively once it reaches operating temp  ). I warm it up for at least 3 minutes each morning and nurse it until operating temp - a bit less warm-up in the afternoon. What do you guys think? How do I check for fuel leaks? I have a 8000km oil and filter service interval regimen but I may need to shorten that, the gears are starting to get noticeably notch or clunky. I am going to try Rotella T6 diesel oil this time.
Last edited by foglefar; 08/01/2014 6:52 AM.
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: May 2010
Posts: 5,720
Check Pants
|
|
Check Pants
Joined: May 2010
Posts: 5,720 |
Wouldn't another avenue for fuel in your oil be piston ring blowby? The Diesel engine oil seems a logical approach, as typically the oil in a D. engine becomes quite runny with fuel admixture and in a very short run time. A bleed down test on each cylinder might be revealing. If one cylinder tested out noticeably weaker than the other, a hone job or a new sleeve with new rings may solve your problem. My two and a half cents, cheers.
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
Thanks Ryk. I hadn't thought of rings. Unfortunately I am a self taught maintenance guy with no meaningful practical experience in engine breakdown and mechanics. Checking the valve clearances was my most significant challenge so far.. I guess I need to get someone experienced to test and hopefully eliminate the rings as a cause. I don't really want to be up for a top end rebuild so soon (34000kms). Thanks also for your PM with added detail but it sounded like a foreign language to me. 
Last edited by foglefar; 08/03/2014 12:21 AM.
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
OK after some thought I think I can do this - just basically a compression check right? I'll do some research on how to and tools required. I don't know why it sounded too tech for me before. Thanks Ryk. 
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: May 2010
Posts: 5,720
Check Pants
|
|
Check Pants
Joined: May 2010
Posts: 5,720 |
A bleed down test uses a faux sparkplug or a simular fitting to allow you to pump the combustion chamber full of air on the compression stroke, a valve that can be shut off, to maintain the pressure, and a gauge that shows how much pressure the chamber can hold and (timed) how long before it all leaks out. Ostensibly more accurate that a comp test. The simple test you are referring to, is still a good first start. Your looking for your readings to be within' (I'm guessing here) 3-4 lbs. On cars motors, the books usually say 5 lbs max variation.
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Sep 2006
Posts: 1,835 Likes: 3
Learned Hand
|
|
Learned Hand
Joined: Sep 2006
Posts: 1,835 Likes: 3 |
just my two cents, but, knowing the life expectancy of these engines, wouldn't the most likely source be the injector(s)leaking residual pressurized fuel after shutdown. And, considering the described use of the bike, wouldn't such an occurrence lend that source to occur a an accelerated rate. And couldn't the source possibly be attributed to todays fuel quality and formulation, and the solution possibly as simple as a good injector cleaning. I think a simpler first attempt.
2004 Triumph Speedmaster (J Lo) 2006 Yamaha Stratoliner (Adele)
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: May 2010
Posts: 5,720
Check Pants
|
|
Check Pants
Joined: May 2010
Posts: 5,720 |
Yea, if the injector is slightly buggered, that could slow down the fuel impulse enough that the fuel is still coming out past its optimum time. Still the only route for the fuel to get to the oil is over the rings and down the piston. If I'm missing something here, plumb me up. Hmm, bad valve seal? An way, Richard will get to the bottom of it.
Last edited by Ryk; 08/02/2014 9:50 PM.
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Sep 2006
Posts: 1,835 Likes: 3
Learned Hand
|
|
Learned Hand
Joined: Sep 2006
Posts: 1,835 Likes: 3 |
Ryk, my hypothesis is based on the following; 1. fuel leaking past an injector when the engine is at rest and not influenced by cylinder/piston compression will leak past rings at some rate regardless of ring/cylinder wall condition simply because of the low viscosity of gasoline. 2. the problem is unlikely to occur while running because the fuel, unless the engine is running obviously poor, will combust before it blows beyond the rings - therefore is most likely happening while the engine is at rest. 3. due to the repeated, short trips of the bike, the probable slight fuel leak into the crankcase does not 'vaporize' off as effectively as in an engine that gets more significant mileage on a regular basis. I have no doubt that bad rings or valves may produce the same results. I just can't imagine a Triumph twin would likely display such a condition until very late in the engine's life cycle.
2004 Triumph Speedmaster (J Lo) 2006 Yamaha Stratoliner (Adele)
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
Quote:
A bleed down test uses a faux sparkplug or a simular fitting to allow you to pump the combustion chamber full of air on the compression stroke, a valve that can be shut off, to maintain the pressure, and a gauge that shows how much pressure the chamber can hold and (timed) how long before it all leaks out. Ostensibly more accurate that a comp test. The simple test you are referring to, is still a good first start. Your looking for your readings to be within' (I'm guessing here) 3-4 lbs. On cars motors, the books usually say 5 lbs max variation.
OK I got the wrong idea. I thought you meant a compression test in a dry chamber as a base line and then a second test after squirting in a bit of oil. I assumed the oil would temporarily seal any poorly fitting ring. A significant increase in compression in the second test would indicate a problem with the rings. Obviously that is not what you meant, but would it work?
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: May 2010
Posts: 5,720
Check Pants
|
|
Check Pants
Joined: May 2010
Posts: 5,720 |
Yes, that's the old school method of determining the reason for a cylinder with questionable compression. Test dry, then test with oil, if comp jumps up the rings are suspect, if comp stays the same, that points to the valves are bad. You can use the oil trick with a simple comp test or the bleed down. Do a compression test and go from there, as was mentioned, and hope for the tests to run close on both cylinders.
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: May 2010
Posts: 5,720
Check Pants
|
|
Check Pants
Joined: May 2010
Posts: 5,720 |
Quote:
Ryk, my hypothesis is based on the following; 1. fuel leaking past an injector when the engine is at rest and not influenced by cylinder/piston compression will leak past rings at some rate regardless of ring/cylinder wall condition simply because of the low viscosity of gasoline. 2. the problem is unlikely to occur while running because the fuel, unless the engine is running obviously poor, will combust before it blows beyond the rings - therefore is most likely happening while the engine is at rest. 3. due to the repeated, short trips of the bike, the probable slight fuel leak into the crankcase does not 'vaporize' off as effectively as in an engine that gets more significant mileage on a regular basis. I have no doubt that bad rings or valves may produce the same results. I just can't imagine a Triumph twin would likely display such a condition until very late in the engine's life cycle.
I think you have a valid point and definitely worth looking into. Are the FI models port injected or throttle bodies? I don't have FI on my two scoots, but it was my understanding that they use T Bodies. Your absolutely right about that if un metered fuel is present, the best fitting rings in the world will leak and also cause undue wear at startup from dry cylinders. I do not know what's involved with pulling the injectors, but it's worth a first look.
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
Injectors are in the throttle bodies. I've just been looking at how to pull them. I wouldn't know what to look for - I was just thinking of getting the injectors refurbished.
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
Quote:
Yes, that's the old school method of determining the reason for a cylinder with questionable compression. Test dry, then test with oil, if comp jumps up the rings are suspect, if comp stays the same, that points to the valves are bad. You can use the oil trick with a simple comp test or the bleed down. Do a compression test and go from there, as was mentioned, and hope for the tests to run close on both cylinders.
Ho w much oil do you squirt in the plug hole? I was going to say plug port but plug hole sounds better. 
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: May 2010
Posts: 5,720
Check Pants
|
|
Check Pants
Joined: May 2010
Posts: 5,720 |
Close to a Tablespoon should suffice, just give it a few minutes to drizzle down the piston sides and engulf the rings.
|
|
|
Re: Significant fuel dilution in oil analysis
|
Joined: Mar 2005
Posts: 2,419
Oil Expert
|
|
OP
Oil Expert
Joined: Mar 2005
Posts: 2,419 |
Thanks mate.
Cheers, Richard
~~~~~~~~~~~~
09 America, Staintune Pipes, K&N, Breathe, Hagon Nitros, AI & O2 removed, tune 20184 (modified), MTX-L a/f gauge
|
|
|
|
|
