Adding Diesel to Gas Helps Fight Rust

[Tom Wesenberg]

I've read about guys adding a quart of diesel to corn crap gas to help with vapor lock. I haven't tried it yet, but always thought it was a good idea, and should also help the gas tank to not rust. I just came across this on another car site:

"I run a testing laboratory at an oil refinery. Gasoline composition varies quite a bit from season to season ( Thank you EPA). During the summer months the gasoline formulation tends to have more of the "light ends" which lowers the initial boiling point. This is primarily from the addition of butane. Butane is cheap and boosts octane so refiners add as much as they can during the EPA defined season.
Gasoline is not like water. Water is a pure substance that always boils @ 212 F ( at standard temperature and pressure). Gasoline is a mixture and it boils off 1 component at a time. During the summer you will find that it starts to boil around ambient temperature and as low as 70 F. It continues to boil off the lighter components until they are gone. So if you distill gasoline it starts to boil at very low temperatures and continues to boil until the heaviest components boil at about 437 F.
Adding diesel to the tank will not affect the IBP ( initial boiling point). It only serves raise the final boiling point (FBP). Raising the FPB ends up leaving a residue which coats the surfaces and helps protect from rust, etc.
Pressuring your gas tank effectively raises the IBP so that your gas does not boil in the tank. The higher the pressure, the higher the IBP. If your tank is not pressurized then your only solution is to isolate and insulate."

[Ford_Freddie]

Here in Germany we have no choice. We have to use gasoline with at least 5 % of ethanol. Many owners of vintage cars use smokeless two-stroke-engine-oil 1:100 (API-TC, JASO-FC). An old mechanic told me that this kind of oil prevents the gas tank from rusting, is a benefit for the Model A valve train and protects all kind of gaskets in the fuel system. I use it regularly. The plugs aren't fouled and the exhaust doesn't smell like a two-stroke-engine.

[Y-Blockhead]

Originally Posted by Tom Wesenberg

... During the summer months the gasoline formulation tends to have more of the "light ends" which lowers the initial boiling point. This is primarily from the addition of butane. Butane is cheap and boosts octane so refiners add as much as they can during the EPA defined season.

That statement is flat ass wrong. I worked for Chevron USA for 25 years. In the summer the refineries have to LOWER the vapor pressure of the gasoline blend (thus raises the boiling point of gasoline during HOT weather). Adding butanes would increase the VP. That's one of the reasons gas costs more in the summer because they CAN NOT blend in the cheaper butanes.

There are other factors that regulate the vapor pressure of gasoline also.

[mrtexas]

Originally Posted by Tom Wesenberg

I've read about guys adding a quart of diesel to corn crap gas to help with vapor lock. I haven't tried it yet, but always thought it was a good idea, and should also help the gas tank to not rust. I just came across this on another car site:

"I run a testing laboratory at an oil refinery. Gasoline composition varies quite a bit from season to season ( Thank you EPA). During the summer months the gasoline formulation tends to have more of the "light ends" which lowers the initial boiling point. This is primarily from the addition of butane. Butane is cheap and boosts octane so refiners add as much as they can during the EPA defined season.
Gasoline is not like water. Water is a pure substance that always boils @ 212 F ( at standard temperature and pressure). Gasoline is a mixture and it boils off 1 component at a time. During the summer you will find that it starts to boil around ambient temperature and as low as 70 F. It continues to boil off the lighter components until they are gone. So if you distill gasoline it starts to boil at very low temperatures and continues to boil until the heaviest components boil at about 437 F.
Adding diesel to the tank will not affect the IBP ( initial boiling point). It only serves raise the final boiling point (FBP). Raising the FPB ends up leaving a residue which coats the surfaces and helps protect from rust, etc.
Pressuring your gas tank effectively raises the IBP so that your gas does not boil in the tank. The higher the pressure, the higher the IBP. If your tank is not pressurized then your only solution is to isolate and insulate."

Bad idea IMHO. Probably will smoke and make your engine run on. Diesel has a boiling point of 500-650F. How do you think that will vaporize in your carburetor? It won't.

Go ahead and try it and report back the results. The worst that could happen is you have to drain your tank and throw out a whole tank of contaminated gas.

Another consideration is the properties of gasoline vs diesel. Gasoline is blended so that it does not ignite by compression. It ignites by spark. Diesel is blended so it ignites easily by compression. You don't have enough compression in a Model A, 4.2:1 to ignite diesel by compression which is 20:1+.

This is IHO based on working 31 years as a chemical engineer in an XOM refinery. I was never asked my opinion as to whether blending diesel in gasoline was a good idea as the maximum endpoint(EP) spec for gasoline is 437F and diesel EP is 650F. Obvious isn't it?

[Brianfrench65]

I always add about 4 ounces of Marvel Mystery oil to a fill up. I learned that back in the 70's, and I have been doing that since, but only to older, non emission controlled and only to the seldom used antiques.

[Tom Wesenberg]

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Originally Posted by Y-Blockhead

That statement is flat ass wrong. I worked for Chevron USA for 25 years. In the summer the refineries have to LOWER the vapor pressure of the gasoline blend (thus raises the boiling point of gasoline during HOT weather). Adding butanes would increase the VP. That's one of the reasons gas costs more in the summer because they CAN NOT blend in the cheaper butanes.

There are other factors that regulate the vapor pressure of gasoline also.

I agree with you that they guy got his vapor pressure mixed up. I was just posting what he wrote and I do like the idea of adding diesel to help keep rust out of the tank. I also like the idea that it would add some lubrication to the dry gas we have to burn these days, especially the corn crap gas.

[CYB4]

Me the same, I add some twostroke oil to the German "crap-gas" with at least 5% ethanol or I fill my car with AVGAS 100LL from my airport. Especially during the winter time the hygroscopic ethanol can separate some water, which will cause rost in the tank.

[Mitch//pa]

i would never subscribe to adding diesel as a supplement to any cars fuel system old or new

[Y-Blockhead]

Originally Posted by Tom Wesenberg

I agree with you that they guy got his vapor pressure mixed up. I was just posting what he wrote and I do like the idea of adding diesel to help keep rust out of the tank. I also like the idea that it would add some lubrication to the dry gas we have to burn these days, especially the corn crap gas.

Hi, Tom. Sorry I came on a little strong and it certainly wasn't pointed at you. It just "flicked my switch" that someone that claims to "work in a test laboratory" would write something like that.

When changing specs from winter to summer gas it is a lot more than just adding and/or removing butane. Many different areas of the refinery have to change their way of operation. For example in our plant in order to change the VP we have to run the distillation column hotter to meet specs and run samples through out the day to ensure we are not "Off Test". And this is just one piece. End of rant.

[mshmodela]

Maybe the solution is to cool the zenith... Not an easy trick.

[hardtimes]

Originally Posted by Y-Blockhead

That statement is flat ass wrong. I worked for Chevron USA for 25 years. In the summer the refineries have to LOWER the vapor pressure of the gasoline blend (thus raises the boiling point of gasoline during HOT weather). Adding butanes would increase the VP. That's one of the reasons gas costs more in the summer because they CAN NOT blend in the cheaper butanes.

There are other factors that regulate the vapor pressure of gasoline also.

Thanks for your experienced/knowledgeable input ! IMO, we (EARTH and a hobby like ours) need more people who are not afraid to tell 'truth' as they experience/know it, eh !

You are just the man that may be able to answer a gas problem/question that came to me at 7000' very recently. My '04 injected 500 cu in truck engine light came on, after filling up with some crap gas in Bishop, Ca.
A buddy , who owned a repair shop, advised me ,to put some Chevron..'Techron' into the gas tank. Wow, within several miles, the engine light went out and the 'light' in my head came on ...regarding my Model A/B engines. What good or harm could come from adding Techron additive (fuel system cleaner) to my Model A gas tank.
Appreciate any thoughts that you have regarding this question.

[wrecker king]

Really nothing, it has a strong detergent additive, it will clean the carb, valves etc.

John G

[Patrick L.]

I've heard the diesel thing since I was young, I don't think I've tried it. But, I do tend to add motor oil most of the time. I'll add a qt of cheap or old stuff I always seem to have hanging around. The old wives tale is that it keeps the carbon soft and helps with tank rust. This may be one of those tales that I believe, at least it doesn't hurt. Doesn't smoke either.
When it comes to mixing diesel and gasoline I do it the other way around. I'll add a little gas to diesel in really cold weather to a diesel that is a hard starter.

[barkleydave]

MMO does about the same... since it is a Very light oil it works as a detergent and also when fuel evaporates in your carb the oil tends to stay behind and helps prevent varnish build up. Never saw much use for it as an oil additive but have used it for years in boats and old cars and small seldom used engines.

[mrtexas]

Originally Posted by hardtimes

A buddy , who owned a repair shop, advised me ,to put some Chevron..'Techron' into the gas tank. Wow, within several miles, the engine light went out and the 'light' in my head came on ...regarding my Model A/B engines. What good or harm could come from adding Techron additive (fuel system cleaner) to my Model A gas tank.
Appreciate any thoughts that you have regarding this question.

Wow problem solved by adding Chevron nerdy marketing words to your tank. I wish it were that easy. Chevron or was it Shell used to blare "our gas has Platformate." I guess they decided that "Platformate" sounded manly or vaguely mysterious. Manly gas for manly muscle cars. Well most gasoline has detergents(Techron) and reformed naphtha(platformate) to put it in more technical terms.

Don't bet that you actually get Chevron gas at a Chevron gas station either. You are 9 times out of 10 getting gasoline from the nearest refinery. The Oils do this to save shipping costs, that is trading out with competitors to save excessive shipping costs.

Gasoline is a commodity with little to no difference between brands.

Me I fill up at XOM stations since I get a 10% discount being a retiree.

[mrtexas]

Originally Posted by Patrick L.

When it comes to mixing diesel and gasoline I do it the other way around. I'll add a little gas to diesel in really cold weather to a diesel that is a hard starter.

That would work

[cuzncletus]

There is a bill in Congress introduced by Bob Goodlette, R-Va., to overturn the Renewable Fuel Standard laws; i.e., ethanol. Any positive environmental benefit from ethanol is questionable; the profits reaped by large farmers and mega-agri corporations are not. Iowa is a primary producer of corn. It's also home of the first Presidential caucus. Politicians have to pander to Iowa to win votes and one of the main ways is to support the RFS. It all boils down to politics and money. How unusual.

Write your congressman supporting Goodlette's bill to overturn the RFS. I have. The whole country is paying in increased gas prices, repairs, and grocery costs to benefit a greedy few.

[Patrick L.]

Originally Posted by cuzncletus

There is a bill in Congress introduced by Bob Goodlette, R-Va., to overturn the Renewable Fuel Standard laws; i.e., ethanol. Any positive environmental benefit from ethanol is questionable; the profits reaped by large farmers and mega-agri corporations are not. Iowa is a primary producer of corn. It's also home of the first Presidential caucus. Politicians have to pander to Iowa to win votes and one of the main ways is to support the RFS. It all boils down to politics and money. How unusual.

Write your congressman supporting Goodlette's bill to overturn the RFS. I have. The whole country is paying in increased gas prices, repairs, and grocery costs to benefit a greedy few.

I've written years ago, wouldn't hurt again I guess.

Do you know how hard it is to try and convince some folks about the higher prices in the grocery stores and the non-good effects of this fuel. But then when one watches Jay Walking or Watters World, etc. it makes sense.

[BlueSunoco]

MMO and Seafoam seem to help. A lot.

Yet to try Startron they say it is the better of the two between it and Sta-Bil.

Sta-bil 360 expensive stuff, 20 bucks a pop at Advance Auto Parts

[mshmodela]

Seems one only needs a clear 5 gal bucket.. to get the Ethanol out

https://www.youtube.com/watch?v=OfZgDkRwAUk