Hey all,
I've got a dumb question.
Can you take a gasoline engine and convert it to use diesel?
Is it a lot of work?
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I have an old yet reliable gasoline generator which I'd like to convert to diesel if possible. Less variaties of gas laying around the place, you know.
thanks, Beetlebrain
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Can you take a gasoline engine and convert it to use diesel?
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All things are possible; given enough time and money. [img]/forums/images/icons/laugh.gif[/img] But I'd say to forget it. Remember that a diesel engine is compression combustion instead of spark ignition, so the diesel engines have 2 to 3 times the compression ratio of a gasoline engine. So things like the pistons, rods, and maybe crankshaft and the block itself aren't strong enough to a diesel.
Like Bird said, anything is possible. In order to get the compression ratio needed for diesel ignition you'll either reduce the cylinder bore and/or increase the piston stroke. You'll also have to strengthen the block/head to account for the higher pressures. You probably don't have sufficient clearance in the crankcase to increase the stroke much (longer throw crankshaft) and it will require a deeper cylinder bore which may not fit. Reducing the bore/piston diameter will be your best bet but now you're seriously reducing your displacement and resulting horsepower.
I could talk (type [img]/forums/images/icons/tongue.gif[/img] ) for a long time on subjects like this as I enjoy it but in the end you'll be much better off either leaving it gas, swapping the engine for a diesel or swapping the whole gen-set for diesel powered one.
It's a bit like a sex-change operation (sorry, it's the best analogy I could think of). Yes, it's possible and yes, it's been done but it's complicated, quite un-natural and will you really be happy with the results [img]/forums/images/icons/smile.gif[/img]
OK, you've really got me thinking now which is a dangerous thing. Yes, you'll need a long throw crankshaft to get the compression ratio up. I was originally thinking the extra stroke would come at the bottom of the cylinder which will get tight to the crankcase. Why not put it at the top. Increase the cylinder deck height with some sort of spacer. You'll have to sleeve the cylinder to get over the parting line. This all still assumes you've got crankcase clearance for that new crankshaft.
OK, next up is cam. Valve timing for a diesel is likely different than a spark ignition so plan for a new camshaft. Is this overhead valve or side valve? Valve stems/pushrods will have to change depending on which you have. You could strengthen the whole block/head with external tie-rods. Main bearings will likely need to be strengthened.
Next stop, cooling. Is this air cooled? There are some air cooled diesels but water cooling is much more common. Hmmm, this is going to be tough. Perhaps the cylinder head spacer can have a bunch of fins for air cooling. Head will have more heat to dissipate also. More fins!
Fuel delivery is next. Piece of cake if you can pick up a single cylinder diesel system from another engine. You'll need to modify the spark plug hole in the head for a fuel injector. The injection pump will run off the camshaft so plan either a direct drive or gear drive. Connect the pump to the injector with hard tubing. Pitch spark plug, coil, points, condensor etc.
Obviously, most of this is somewhat tongue-in-cheek but again, it would be possible but seriously difficult and very expensive. A good project for a student going into engine design perhaps [img]/forums/images/icons/smile.gif[/img]
Thanks Bird, egon, & RobS
Sounds like way too much work & $$. We already use diesel for the machinary.
Ok here's another question.
I want to use a nice new 55 gallon drum for holding & storing some extra gasoline for the generator.
Does anyone have any handy homemade ideas for making a "vent" that would fit in the small opening, the other one will have a crank pump.
I've seen some vents for sale on line, but I thought maybe I could just use a plug with a drilled hole or something like that, ofcourse starting that with an empty drum first. [img]/forums/images/icons/grin.gif[/img]
Thanks all for the eyeopening input, Beetlebrain
Thanks Bird,
Say is there much loss from "evaporation" of the fuel?
Sometimes, I'd swear that I had more fuel in the 5 gallon containers [little red ones] than what I end up "feeling". You know kinda like some evaporated since last month or what not. Any thoughts or facts on that?
Beetlebrain [img]/forums/images/icons/confused.gif[/img]
You did say storing gasoline, right? How long do you intend to store it? Gasoline goes stale pretty quickly. I wouldn't store it for more than a couple of months. Yet another good reason to do your diesel conversion (OK, just messing with you now [img]/forums/images/icons/wink.gif[/img] ). Diesel will last a lot longer in storage than gasoline [img]/forums/images/icons/smile.gif[/img]
You're certainly going to have some evaporation, and I don't know how much, but won't you have that with any kind of vent? And I agree with Rob that gasoline does get stale after awhile so if I'm going to have it longer than a couple of months, I'll add some Stabil.
I guess we've all heard of gasoline getting "stale", but not being a chemist, engineer, etc. I don't know how long it takes nor how bad of a problem it is if it does get old. But everytime I hear about gasoline getting stale, I think of a little boat motor I had many years ago. In 1970, I bought a new 2hp Johnson outboard motor to use on a canoe; 2-cycle of course. with a one quart fuel tank. In the Fall of 1971 I was sent to Northwestern University and left the little boat motor in the garage in Dallas with the fuel tank full, and when I returned in the summer, we had a new house built, had to get moved, etc., so that little boat motor sat, unused, with a full tank of fuel for well over a year before I got to use it again. So, instead of dumping that gas out, I decided to try it with the old gas. Hmmm, started just as easy as ever and ran just fine. So I spent the day fishing, eventually ran that gas out, and dumped a tank of fresh fuel into the tank, started it up again, and I do believe the little motor picked up about 500 RPM instantly. [img]/forums/images/icons/laugh.gif[/img] Of course that was before I ever used anything like Stabil. Apparently old gas still works; just not quite as well as fresh. [img]/forums/images/icons/wink.gif[/img]
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