Gas Ran in a Diesel Tractor !

[doitmyself]

Today one of my seasoned employees had a monumental mental lapse and filled one of our 26hp compact John Deere tractors with gasoline. He returned after a half hour of brush hogging (grass) and said it was smoking more than normal and the exhaust smelled unusual.

GRRRRR. This tractor is only 5 years old with about 600 hours on it...almost new. I'm guessing that the fuel mixture was about 60%-70% gas.

I know that the pump and injectors could be damaged. The oil might be diluted by gas if the mixture washed down the cylinders.....maybe piston/ring damage.

I will purge the fuel system, install new fuel filter, change the oil and filter....maybe do a UOA. Fire it up and pray.

What else can I do? What else to look for? IFFFF it seems to run o.k., should I have the JD dealer do extensive diagnostics on the components for verification? I'm paranoid that a small problem now might escalate slowly into failure over the next year on any of the components listed above.

Thanks for any advice.

I'm having a "Critic" week.

 

[Steve S]

Nothing has happened, all the stuff you are thinking that has happened didn't. Drain the gas out and put diesel in the tractor . No need to change the oil,or do a uoa or pray about the tractor.

 

[RH+G]

I would do as u say and listen to how it runs after u change the oil and purge the fuel system. U might be surprised that it runs fine. I would also put sum diesel fuel treatment/conditioner in their if it starts up good.

I have seem some people do that with diesels and most of the time they run fine with no problems afterward. Otherwise they run like [censored] make noise and u know almost on the first tank that something is wrong

 

[The motor guy]

Unless you have a high pressure common rail diesel engine in your tractor it should be fine. Just drain the tank and refill with diesel maybe even some tc-w3 2 stroke oil for extra lubricity for the next few tanks.

 

[fastbear]

Had the misfortune of filling a near empty powerstroke up with gas once. Truck started running poorly after two miles. Drove another mile to the house. Next day switched to a full diesel tank, after changing the fuel filter and filling with MMO. Engine settled down shortly and ran fine right up to trade day. Also, siphoned out the badly diluted gas/diesel mix and donated that to a gas p-up.

 

[antonmnster]

I thought I heard somewhere that gas in a diesel engine will cause major damage while diesel in a gas engine will just cause it to stall. For giggles once, I ran 1/2 gas + 1/2 diesel in a 18 hp Kohler and it didn't seem to notice.

 

[NateDN10]

Originally Posted By: antonmnster
I thought I heard somewhere that gas in a diesel engine will cause major damage while diesel in a gas engine will just cause it to stall.

Logically, it seems like it would be the other way around. Diesel would have a very low octane and thus a tendency to preignite and damage a gas engine, while gas in a diesel engine might not ignite at all.

 

[doitmyself]

Things I was told:

In a diesel engine, the fuel provides lubrication to the pump and injectors which run under high pressure and close clearances.

Diesels operate under very high compression, so running higher volatile gasoline could be problematic.

Gasoline is thinner and will be fed faster into diesel cylinders than can be burned, allowing for piston wash down (damage and oil contamination).

Did I miss anything? It will be a day or before I can address this problem.

 

[47HO]

I would think that diesel would have a higher octane rating, allowing for the extra high compression of diesel operation.

JMO

 

[Steve S]

Originally Posted By: 47HO

I would think that diesel would have a higher octane rating, allowing for the extra high compression of diesel operation.

JMO
Diesel oil is rated by a cetane.

 

[Steve S]

Originally Posted By: doitmyself
Things I was told:

In a diesel engine, the fuel provides lubrication to the pump and injectors which run under high pressure and close clearances.

Diesels operate under very high compression, so running higher volatile gasoline could be problematic.

Gasoline is thinner and will be fed faster into diesel cylinders than can be burned, allowing for piston wash down (damage and oil contamination).

Did I miss anything? It will be a day or before I can address this problem.
I'll tell you to drain the tank and filter ,fill the tank with diesel and run the engine .

 

[NateDN10]

Originally Posted By: 47HO
I would think that diesel would have a higher octane rating, allowing for the extra high compression of diesel operation.
JMO

Octane basically measures resistance to heat ignition. In a diesel engine the heat from compression is what ignites the fuel, so a low octane rating is what you want. Cetane rating is almost like the opposite of octane (not really, but it can be thought of that way) - it measures how quickly ignition follows injection.

FWIW, according to Wikipedia, diesel has an octane rating of 25. (link, under the "Energy Content" section)

 

[scurvy]

Originally Posted By: antonmnster
I thought I heard somewhere that gas in a diesel engine will cause major damage while diesel in a gas engine will just cause it to stall.


That's roughly correct. Cetane and octane numbers are roughly the opposites from each other - CN being a measure of how well a fuel self-ignites, ON being a measure of how resistant it is to self-igniting - diesel in a gasser typically just makes the fuel very difficult to ignite.

Diesels have the injection pump and injectors themselves lubricated by the fuel as well, so putting in a much less lubricious fuel can do bad things... but it may have done no harm, either.

DIMS, at this point you've got nothing to lose by changing the oil, draining the fuel tank, replacing the fuel filter & purging the fuel lines. Then refill with diesel and a heavy dose of Power Service, Howes, etc... and see if it runs OK. If it does... keep on hoggin'.

For whatever reason, all the pre-CR TDIs I've heard of that had gas contamination in the fuel ran better once the problem was corrected. Gross fuel contamination could lead to needing a rebuilt IP & refreshed injectors but typically those cars didn't run for half an hour after being fueled... they usually conk out very quickly after leaving the gas pump.

 

[cjcride]

Compression ratio of Diesel engine 20/1 Gas engine 8.2/1
Hence gas will detonate before Bottom Dead Center = Engine Damage.

 

[cjcride]

Originally Posted By: cjcride
Compression ratio of Diesel engine 20/1 Gas engine 8.2/1
Hence gas will detonate before Top Dead Center = Engine Damage.
Edited

 

[fdcg27]

SteveS,

I love your common sense replies to topics.
Did you customize your sig for this one?

 

[Steve S]

Originally Posted By: fdcg27
SteveS,

I love your common sense replies to topics.
Did you customize your sig for this one?
I copied and pasted it from an article. I am not smart enough to think of something so good.

 

[Schmoe]

Sounds like it was in fact, still running when your employee noticed the problem. That tells me that there was obviously enough diesel in the tank whereas it hasn't bombed on itself. So, drain and re-fill with diesel and just let it run. The oil will clean itself if you let it run long enough. Don't beat him too hard, at least he had the sense to shut it down after noticing the problem!!!

 

[doitmyself]

Originally Posted By: Schmoe
Sounds like it was in fact, still running when your employee noticed the problem. That tells me that there was obviously enough diesel in the tank whereas it hasn't bombed on itself. So, drain and re-fill with diesel and just let it run. The oil will clean itself if you let it run long enough. Don't beat him too hard, at least he had the sense to shut it down after noticing the problem!!!


Follow up: I drained and bled the system well. Estimated that the mix was about 50/50 gas and B5 diesel (things in my favor).

I added a good dose of John Deere Fuel Treatment (Stanadyne?) to the new fuel and she fired up well, smoked a tad for a few minutes and then seemed to mellow out and run fine.

I will keep an eye out for any changes and see what happens. The (student) employee was raised on a farm. It was simply a mental lapse, not stupidity (been there, done that myself). He beat himself enough without my help, and yes, he did have the sense to shut it down.

Will keep my fingers crossed. I told Steve S. that I lost a Kubota tractor engine 8 years ago when someone let it severly overheat due to a plugged radiator screen! This is part of my work environment, no matter how well I supervise....thus, my "over reaction".