A little gasoline in the diesel

[zstine]

Originally Posted by Bill Seal

Since a diesel engine has NO fuel in the cylinder until the injector squirts, how can you have pre-ignition?

because the injector timing is before TDC.

[MikeHoncho]

Originally Posted by Cadence

I've seen it. A neighbors daughter, 15, thought she was doing good to top off Mom's tank. Gas station may have been 1/2 a mile away. The woman came over and asked me to look and see what I thought. It was you need a new motor. The rod was right through the block.
I wouldn't bet on the gas and diesel becoming homogenous.
For what is worth?

I would

[Siberian Sea]

I drove a semi truck for years up north in the Arctic and in extreme winters we would put a gallon of gasoline in each tank 150 gallons of number 2 diesel to keep it from jelling up. Never once was there a problem doing this. I think you can run your engine fine with this. Just keep adding diesel each time you can to dilute the mix.

[NCWDave]

^^^^Siberian has it right. I would run it, no worries. I would add a gallon of 2stroke oil. I use 2stroke oil in any tank of Ultra Low Sulfur Diesel that goes in to a fuel system built before about '05 because USLD has very poor lubricity. It is very hard on older injectors and IPs

[carrboyd]

45 years as diesel mechanic,diesel and petrol will mix like whiskey and dry,done this myself when fuel stop was shut on remote road.Added approx 10 litres unleaded petrol to half full 70 litre tank in direct injection diesel workshop truck,engine diesel rattle was a bit louder and i changed down to let engine spin to avoid detonation damage,10 years later the engine has not been touched apart from routine servicing.
As others have said here ,don't worry your Ford will love it at those ratios

[Aguabago]

Thanks for all of the responses. What I am going to do is mix in 120 liters (30 gallons) of jerry cans, which will get the ratio down to 4% petrol to diesel. Then throw in some diesel additive that I have on hand. Then give it a go. The engine uses about 2 liters per hour, so its going to take awhile before I'll be able to get it down far enough to add enough additional diesel to reduce the percentage significantly.

[BillKny]

So as always with the internet you get three answers:

• it will be fine.
• It will be a disaster.
• I don't know, but will say something anyway.
  

Have you ACTUALLY learned anything from this that was more valuable than doing your own research?

[Compass790]

Originally Posted by Aguabago

Thanks for all of the responses. What I am going to do is mix in 120 liters (30 gallons) of jerry cans, which will get the ratio down to 4% petrol to diesel. Then throw in some diesel additive that I have on hand. Then give it a go. The engine uses about 2 liters per hour, so its going to take awhile before I'll be able to get it down far enough to add enough additional diesel to reduce the percentage significantly.

Hmmm? 2 litres per hr, surely you mean 2 gallons per hr for a 75hp?
I think you are more likely to be killed by lightning than do any damage to a naturally aspirated, mechanical injection diesel @6% if mercedes recommended a 10% mix for winter use. But I can see the cautious approach has some appeal. An each way bet if you like.

Be interested to hear if you notice any difference in engine sound/performance.

My guess is you wont but I dont know as I've only put small amounts of petrol in the diesel as a biocide.

[Steve Bean]

For several years I had 2 1980 .Mercedes diesel station wagons. The owner's manuals advised adding up to 30 percent of gasoline in very cold weather if winter diesel (#1 diesel) was not available. It was specified to use regular, not premium gasoline. My son and I drove the cars thousands of miles on used vegetable oil from restaurants, sometimes thinned with 10 percent gasoline. Never separated, never exploded.
..

[Aguabago]

Originally Posted by BillKny

So as always with the internet you get three answers:

• it will be fine.
• It will be a disaster.
• I don't know, but will say something anyway.
  

Have you ACTUALLY learned anything from this that was more valuable than doing your own research?

The opinions and advise is just that, and lots of that has been given. If you look at the original post, I was asking for people with experience with similar situations. And yes, I have done lots of internet research, but that was inconclusive.

But I ACTUALLY heard from about a dozen people that have run similar percentages of petrol through their similarly typed diesel engines without issues. I also have heard stories about two situations with auto engines which had higher percentages of petrol run through them that wrecked the engines.

And along the way I learned a few other things from peoples comments.

So I ACTUALLY think the post and thread were worthwhile and provided some valuable information and insights.

[Aguabago]

Yes 2 liters per hour is my average usage. This is a naturally aspirated Ford FSD 2.5 liter engine that I cruise at around 2000 RPM max, more RPMs just uses increasingly more fuel with decreasingly smaller increases in speed. However, I usually set a target passage speed of about 5 knots (that can vary with the particulars of the passage) and put the sails up and motor sail. When I hit the target speed I start incrementally throttling back to maintain the target speed until I can eventually turn the engine off. So my average RPMs are less than 2000. However, even if there is no wind and I motor for a long time at say 2200 RPM, them the most fuel that gets used is about 2.7 liters per hour.

[MartinR]

Originally Posted by Cadence

Best I could fjnd is that gas has a specific gravity of .71 to .77 with the average being .74. I found two on diesel .82 to .95 and ,87 to .92. I would assume they would separate over a period of time? I don't know about corn oil gas?

No, they do not separate. Density has nothing to do with this. Only solubility.

[Compass790]

Originally Posted by Aguabago

Yes 2 liters per hour is my average usage. This is a naturally aspirated Ford FSD 2.5 liter engine that I cruise at around 2000 RPM max, more RPMs just uses increasingly more fuel with decreasingly smaller increases in speed. However, I usually set a target passage speed of about 5 knots (that can vary with the particulars of the passage) and put the sails up and motor sail. When I hit the target speed I start incrementally throttling back to maintain the target speed until I can eventually turn the engine off. So my average RPMs are less than 2000. However, even if there is no wind and I motor for a long time at say 2200 RPM, them the most fuel that gets used is about 2.7 liters per hour.

Thanks for replying. Thats pretty good fuel economy alright. Surprised me as we use about 600cc per hr at 2200 rpm on our 8hp single. Its about 5hp at those revs.

[longjonsilver]

Originally Posted by MartinR

No, they do not separate. Density has nothing to do with this. Only solubility.

Yup, thats right...

[chasfgr]

Above 20% gasoline in diesel, is the point at which you'll invite detonation in mixing chamber diesel - Ricardo'a original work touched on this.


On more modern diesels, with no chamber (unlikely to be found in marine diesels) there is a far greater risk of detonation.
In fact, to prevent waxing in low temperature >-18C) it's quite normal to add small amounts of gasoline (or TVO) to diesel.