gasoline

[diegokid]

Since starting our search for a boat I have heard several people mention problems with their diesel engines relating to algea in the fuel system. I was speaking with my cousin today, "diesel mechanic" and he told me how to stop it. He said some companies have recommended as much as 10% gasoline being added to their diesel, esp when storing. He said he personally mixes 5% in all his diesel vehicles. It made for much better cold weather starting, killed anything in the diesel, acted like a injector cleaner and other benefits.

Has anyone else heard of this?

[diegokid]

Thats why I'm asking. Maybe marine applications are different but he does have over 300,000 miles on his truck without any major repairs.

[Flybyknight]

Diesel engines "knock", and there is knocking and them there is knocking!
I believe that adding gasoline will cause knocking earlier in the compression stroke, effectively robbing the power stroke and putting that energy in to the compression stroke, which will blow the engine.
IMHO
Dick

[hellosailor]

So what, your cousin must think there is a great conspiracy among all the diesel engine makers and diesel fuel vendors, to omit the critical gasoline component from diesel fuel in order to...what? Make diesel engines burn out faster? Make them use more fuel? Ruin them so customers have to replace them more often?

What you cousin is doing just proves how much abuse an engine can take, and still keep on working. Doesn't proive squat about how well that engine is working compared to another engine that is being given proper fuel, now does it?

If you have an algae problem, conifrm that it is an algae problem, and then solve it properly. Maybe an algicide, maybe a different fuel station. And don't forget, there's a thousand experts like your cousin who will tell you that you can buy a Magnet Algae Killer that just clamps on your fuel line and converts the algae into extra power in your fuel. (Save your money, there's another great diesel engine maker conspiracy that sends people around in ninja suits and somehow causes these machines to all FAIL WHEN USED IN LABS.)

[timebandit]

hummm

Originally Posted by cardiacpaul

diesels "knock" for a different reason than gas engines.

Yes, in gas engines, "knock" is caused by 'pre-ignition' at the top of the compression stroke. (before the plug fires).

Diesel knock is caused by very loose tolerances in bearing surfaces and piston/pin tolerances, due to the "space" needed when the higher combustion temps kick in. (and the "firing" of the compressed diesel/air mixture)
After the temps equalize and everything is heated up and expanded, the diesel "knock" becomes less.