what could happen if diesel fuel was ran in a gas engine

[bonghitz71420]

my boss had told me that a previous employee had filled up the tank of a delivery truck with diesel fuel instead of regular gasoline. the truck had a 1976 chevy 454 with a 4 barrel carb. it was driven for about 40-70 miles before anyone relized the problem. i was just wondering how much damage that could of done to that engine. the boss is afraid to take that truck out incase something is internaly wrong with it.
thanks

 

[Metalguy]

Get all the diesel fuel out and if it runs on all 8 cyl. it'll be fine.

 

[JRW261]

its not that bad, its worse for a diesel to run on gasolene if my memmory serves me correct.

Not something Im proud of but I ran out of gas at a camp with a carbed truck of mine. All we had was kerosene and mixed-gas. 2 gallons of kerosene and a gallon of mixed gas and I was off to the gas station. Ran like a slug, but ran. That motor still runs fine. It just fouls plugs and carbons every thing up.

 

[enginebob]

The problem with diesel is, it is harder to atomize it, especially in a carburetor. Next it is a very low octane, and will detonate very easily in an SI engine.
The difference in using gasoline and diesel is the self ignition temperatures. It is just opposite of what you would think it would be. High Cetane means it self ignites faster. Since gasoline is a low cetane it resists self ignition.

 

[rmw]

It is all in the compression ratios.

rmw

 

[jons999]

As an auto dealership tech, believe it or not i see this all the time. Just get all the diesal out of the tank (i disconnect a fuel line and run the fuel pump till the tank is empty). Then fill it up with some high octane gas (to dilute any diesel still in the system). It will be hard to start the car and it will run rough and smoke for a few minutes, but after a quick run down the highway it will be back to normal. This is on EFI engines though, i don't know about carbed engines but it shouldn't be too much different.

-Jon

 

[R3PM]

Ok, Here's one for the record group. I race off road motorcylces and quads. Two weeks ago I got a new supply tip for AV Gas so at 50/50 I could keep the octane up, run cooler and cleaner. Last year it ran great. Picked up 10 gallons and went off to race. stalled at the start and ran terrible at slow speeds. Thought something was up but was planning on tuning the engine this week. This weekend I did the same thing in my quad this time I could (so coudl everyone behind me) smell the fuel and watch the smoke. Tore down the carb, checked jets, cleaned the bowl and everything I could find, changed the plug - which was ugly etc...finally I drained the fuel. Bingo - ran just as good as before. Asked my AV friend - nhe was sure they gave me jet fuel not AV gas - sure enough... I hope these engines are as strong as those vehicle engines. I've done some dumb things before...

 

[Chumley]

Depending on where in the world you buy fuel, often both #2 diesel and unleaded gasoline are between 20% to 40% identical aromatic hydrocarbons. Gasoline tends to have the remainder of the mix in the smaller C5 to C8 hydrocarbons and up to 15% oxygenates (alcohols, ethers) while diesel fuel has the balance in C12 to C18 hydrocarbon molecules plus additives. The "C" number is the number of carbon atoms in the molecules.

See:

http://www.me.mtu.edu/~slpost/CLASS/hcprop.html

for the additional fuel properties.

Chumley

 

[ruggedscot]

Kinda get away with it if its diesel in petrol but the other way..... now that hurts !

diesel is a fuel oil where as petrol is a spirit.

Diesel is used to lube the fuel pump where as petrol will strip the oil off of the bearings and seals in a diesel system. Thus the mechanical parts can be jiggered pretty quickly with petrol instead of diesel.

Been there and suffered. not my fault car in for service and garage filled it with petrol instead of diesel and it messed up the injection pump.

Rugged

 

[enginebob]

Ah the old lube fuel pump deal. I sure hope some one has told the manufactures of years past, that built jerk pumps, and direct injection single plunger distributor pumps for gasoline injection, that gasoline won't lube it. Also the present day electronic fuel injectors too. Oh and the good old Rochester FI unit with that high pressure gear pump that was lubed by gasoline. Man what where they thinking?
And you say diesel in a petro is okay, but gas in a diesel hurts???? All depends on the compression ratio. The CR in a diesel will have to be very high to self ignite gasoline. Since gasoline has a very low cetane. Especially the higher octane variety. It is a missconception that gasoline will explode in a diesel engine. It will knock do to ignition delay if the CR is too low.

 

[ruggedscot]

Hi the point that I was trying to make was that in a diesel spec engine the gear isnt designed to handle petrol due to the properties of petrol, as described. Im sure that if the engine was designed for gasoline then it will have been specced with the right parts and not suffer any detrimental
effects.
I suffered - I had a garage fill the tank with petrol and then try to drive the car, it had a Fiat 1.9 turbo diesel engine built around 97-98 so before this modern direct injection JTD technology. The pump knackered up and the reason given was it had been contaminated with petrol.

Rugged

 

[flyboydave]

When buying aviation fuel, it's easy to tell what you have: 100 octane is green, 100LL (as in "low lead", the most common avgas) is blue, and Jet-A, JP-4, -5, and -8 are white, or straw yellow.

Anyone who's ever received a single flight lesson will know that avgas is either green or blue, and jet fuel is clear or yellow.

Another fuel, combat MOGAS is red, but is for military use.