Should a diesel be longstroke/undersquare?

[Christ]

Originally Posted by bbraden

You'll have to machine a pre-combustion chamber into the head in order for the IDI injectors to work. They're not built to take the hammering that a DI injector will. Plus, you'll have to have a glow plug. I'm betting that with a loose engine and all the WD-40 in the world, it's still not going to start under 30 degrees. I've never actually seen how air injection works... never heard of it before.

Either way, I'm not trying to say it can't be done at all. You can probably do it with enough time and enough money. I guess it's just the German Farmer in me that wants to over-engineer everything. If I build something it's because it's going to be better than I could buy it or so much cheaper that I can deal with all of it's crap that I'll have to put up with.

Anyways, it sounds like you have a pretty good idea of what you want out of this engine, so I'll just leave it at that. Have fun!

I'll have to drill out the spark plug holes anyway, and I thought about drilling them out, tapping them, and screwing in a sort of precombustion chamber. The OEM spark plug holes are way too small to screw in any diesel injector I've ever seen. I'm going to have to check clearances on that anyway, to make sure it won't interfere with the two-valves-per-cylinder.

Basically, the thing I had in mind for the pre-combustion chamber was just a threaded bulb fitting with holes in it that stuck down into the combustion chamber only slightly, and the injector screws into the top of it. If you need, I can make a crappy MS Paint rendition of it and upload it, so you can get a better idea of what I'm talking about.

Air injection seems to be out of the question - its' used on slow-speed diesel engines, I can't find an example used on a high-speed engine. (slow speed = 60-200RPM operational speed).

I don't know how well the engine will start in temps below 30 degrees, but my GM 6.2 Diesel started with a single spray of WD40 in sub-0 temps as long as I warmed up the block for about an hour. It would only take about 10 rotations to start it up, with a quick spray of WD-40 in the intake.

I know what you mean about over-engineering things, it's normally a fault of mine too. I overdo it until it doesn't work, usually.

You have to remember, though. This is a TINKER project. I'm not taking it too seriously, I just want to see what will and won't work, first hand, and WHY it won't work. If, in the end, it works, I might build a few of them and sell them.

I've got small (briggs engines, Kohler engines, etc.. ) that I've also been considering similar projects with... I have one specifically that I don't have a use for, so I was thinking about doing a carb'd spark ignited diesel with it. Again, just to see what happens.

[Christ]

[bbraden]

Okay, I see what you're getting at with the precombustion chamber. I guess that wouldn't be so bad as long as you kept the block warm enough to start it in colder weather. You'll probably want a block heater on it later. I think that your relatively small head (in comparison to most diesels) might still be too thin to live up to the heat transfered into it by IDI. I could be very wrong though. I guess your next step is to just try it and see if it all works. I wouldn't mill the head just because you need all the material you can get there. I'd change your compression ratio by changing the crankshaft because you're going to need closer to 20:1 for IDI.

[dcb]

dude, forget this this, get that twinstar runnin

[Christ]

Originally Posted by dcb

dude, forget this this, get that twinstar runnin

Find me a key and ignition switch that ISN'T $100... and I'm still waiting on the title.. I think I may have to get one for it via "other means"... and it's not old enough to get a BOS from NY state and do it that way.

I guess I can't really expect much different for the price, though.

I think I can get a title for that Dream 90, though, and it appears to have the same frame as the 185, so maybe I can swap the frame over and use that title...

[dcb]

Lol, there were plenty of switches in that old house I bet

[Christ]

Originally Posted by dcb

Lol, there were plenty of switches in that old house I bet

There were. I have them all, too. They had just been put in, so I pulled them out to sell them. I've sold a bunch, so I don't really have them all... but I did make sure to get every last one, as well as GFCI's and Grounded Plugs.

I'm probably just going to solder wires to the old switch (the wires are soldered in) and tape it off, then run a generic keyswitch until I can find something original. I need the switch cover, too, but that's not a big deal as yet.