Spark ignition Diesel engine, AKA your car

[rmay635703]

Originally Posted by mechman600

You seem to see right through me! I have access to free diesel fuel. Like I said, I give this whole idea a 5% chance. If it doesn't work, at least I had fun trying. If it does, I'll be laughing my ass off.

It will work as I said and as Big Dave said there were spark fired diesel powered motors. If I can find the book it described quite plainly several small spark fired diesel motors and had breakouts showing their construction.

Also It would be strongly recommended that if you want the thing to have half a chance of working well enough to do something without breaking to do some modifications to the motor

Perhaps add glow plugs

And as suggested, add something flamable to coax ignition, cut with ether or gas perhaps.

I am uncertain on this regard but it would seem to me that diesel would be much more "lightable" if you increase the compression ratio of the engine just below the autoignition point, likely 12:1 but you also might get a lot of knocking so a cast iron piston would be needed.

As stated, probably will work if its warm enough around you but likely not very well.

And again, why not just get a cheap diesel engine?

They will run cleaner and better on the fuel.

[mechman600]

[QUOTE=rmay635703;165224]....why not just get a cheap diesel engine?/QUOTE]

Because it's a motorcycle. The engine and transmission share the same case. You can't do an engine swap without swapping the transmission as well, and, there's no such thing as a diesel motorcycle engine with a transmission attached to replace mine with.

As for raising the compression, glow plugs, etc: I realize that these things will help. But I'm on a shoestring budget. This is all just to answer the "what if" question, nothing more.

[rmay635703]

If you get into it I remember several adding small amounts of welder poop among other things to the head to increase compression.

Also cutting the fuel with a bit of gas and ether would be a good idea to get it running from cold.

Cheers

[QUOTE=mechman600;165366]

Originally Posted by rmay635703

As for raising the compression, glow plugs, etc: I realize that these things will help. But I'm on a shoestring budget. This is all just to answer the "what if" question, nothing more.

[naturalextraction]

Just cause this is right up my ally and I can talk about it a bit, I add a fairly carefully worded reply. The military has had many engines throughout history that ran on multiple fuels primarily diesel engines. Running on JP fuels and diesel are their main sources. Also better for transport as our armed forces do for obvious reasons. Gasoline being limited in many cases particularly in many other countries. There have been many engines through out it's history that have run on different fuels.
Without getting into much, our current prototype is a motorcycle, (the initial prototype was a car) an old 1981 air cooled 550 Yamaha that runs on any available (commercial) fuel. It runs at as lean as 22:1+ for cruise and 16:1 under boost. Any richer on any type of fuel creates detonation. Yes, running lean does not. Because we're an R&D company I wont get into specifics and there are a lot actually. Understanding hydrocarbon based fuels and their supplemental chemistry is a must. Understanding ICE, spark or compression, is secondary. Utilizing real science throughout the realm of application goes without saying. Knowing a butt load of math is priceless. The stock engine in the bike running with the designed system runs very clean and even NOx is significantly reduced. Which is a particular problem in ultra lean spark ignition engines.
The system extracts the internal chemical energy of the fuel, making more efficient use of the fuel first. (that was rather poorly said actually)The bike runs on a stock ignition module and timing is at it's set parameter for gasoline as it was originally designed for. This has taken about 5 years to get to this point. What took the longest was to have cold start utilizing heavy fuels like diesel. Yes temperatures are significant and everything is controlled via inputs from many areas referencing temperature. mechman600 you'll have fun in your experiments, gaining knowledge is fun!

[mechman600]

Awesome! Thanks for that.

[ShadeTreeMech]

haven't read the whole thread yet, thought I would throw in my 2 cents.

I ran my 74 honda 400cc motorcycle on about 3 gallons diesel to half gallon petrol once. So long as I kept the engine hot (it was air cooled) and played with the throttle and choke it ran it--lacked power, but ran. (I was flat broke and could swipe diesel out of my uncle's tank for his skid loader) As soon as the engine cooled though, it wouldn't start.

I had to nearly choke it almost completely and blow a bit of smoke to get nearly to 65 mph. And high rpms? Forget about it, no chance in hades. But i did clock miles on it, and when it died, I added 2 gallons of petrol, cranked it forever from a jump from my car, and it sputtered back to life.

I've also ran diesel in my cars, but generally while being outnumbered by the gallons of petrol.

[Phantom]

I have thought about doing this on a Buick 3800 but have no means of doing it. I think that you might need to run a hotter spark plug to help keep the temps up for autoignition. As for the fuel injectors if you cannot get it to work with a standard gas one try looking at one from the turbo Pontiac Solstice i believe they it is the one that had direct fuel injection if not one of the motors they used in that car did.

I know that some of the older generators and tractors that ran gas but could also run diesel could only do so when it was started with gas and once warm would manually switch to diesel. About the same set up as using SVO in place of diesel.

[bandit86]

pour diesel in the tank and start it on gas first. once it's warm, then play with it