Well... here goes...

[v8volvo]

Originally Posted by bigbillyboy11

It's been a long time, but I lost motivation in the middle there somewhere. Finally spent some time this weekend pulling the gas motor, swapping cross members and now have the diesel engine bolted in place. Just need to do the wiring and fuel..

For those of you that have done this, how did you handle the fuel supply and return? Did anybody exchange entire fuel tanks? I'm assuming I can use the existing supply line, and is there a return line? I think so, it has a threaded fitting on the end?

Thanks
Jason

Sorry no one responded to this. When I did the swap, I left the gasser fuel system almost entirely intact, though I did change out the fuel filler neck for the larger diesel version. There is a return line in place for the gasser fuel injection system that you can just hook your diesel return directly up to. I ran the gasser fuel pumps for a while to get all the gas out, then gradually added diesel and kept the pumps running until it was just clean fresh diesel coming out. Then I removed the high-pressure electric fuel pump (mounted under the driver's side floorboard), but retained the gasser's low-pressure in-tank lift pump, since it helps the diesel injection pump to have a little bit of low pressure feed. I powered up the in-tank pump using a fuse tap in the fusebox to run it whenever the key was on. Easy. In short you can use the gasser fuel system almost without modification. The only mods that were really necessary were hose and line adaptations to a) eliminate the high-pressure electric pump and filter and put a piece of line in its place, and b) continue that line into the engine bay

You'll find that there is a third line on the gassers, which is a flexible plastic line, that is for the evap emissions system running to the charcoal canister which the diesel doesn't need. In the diesel setup, that line only needs to act as a tank vent to the atmosphere. You can just leave that line open somewhere in the engine bay, in a place where it's not noticeable (for appearance's sake) and not going to get water in it. I ran mine up underneath the battery tray.

Incidentally if you want to use a correct size diesel battery and you have a diesel donor vehicle on hand, you'll want to take the diesel battery tray out and swap it over to the gasser as well.

I'll put up some pictures of my swap shortly, have been meaning to do that for a while.

[MoeTell]

Well the 89 Turbocompresseur cart is probably the most convenient gasser to turn as power supply box and air better and some other things are already in the right place as different from the non turbo vehicles. I transformed a 92 turbo cart and the different device evaluate board was about the only additional thing to alter.

[bigbillyboy11]

Glad the forum is back up. I had given up and just tried it on a whim today.

thanks V8. I didn't know about the in tank fuel pump being low pressure. That will make it very nice, as I was planning on adding a lift pump where the high pressure pump is anyway. I will just replace it with a filter, and run the line up to the IP.

I had originally read that the blue wire up on the firewall that had originally provided power to the coil would be the place to get "key on" power for the fuel solenoid, however, that does not seem to have power. i have the rest of the wiring hooked up and ready to go, but is there another, "key on" wire under the hood that i should tap into, or do i need to run a wire from the fuse block?

It's getting close. I have it cranking over now, and i'm getting excited to finally (five years into the project) take it for a drive.

[v8volvo]

Welcome back!

Sounds like you are getting close to the maiden voyage.... Yeah, it is very convenient that the old LH-Jet gassers have that dual electric pump setup, the one in the tank is just a low-pressure booster pump that only runs about 5-6 psi IIRC, perfect as a supply pump for a diesel IP.

You could put a large-micron pre-filter down there under the floor, that's a good idea, or even just put in a piece of hose and run a line direct to the filter on the engine, or put a pre-filter inline under the hood, many ways to skin that cat. On mine I just bought some brass fitting unions and ran a line right to the motor. Somehow I have a kind of bias against putting fuel filters in hidden places now, probably dates back to an old F-250 diesel I worked on years ago that had a Banks turbo kit on it and also had an additional fuel filter that someone had installed in a crazy location hidden down underneath the brake booster covered up by a bunch of wiring harnesses... The truck ran like dog crap under load and acted just like it had a plugged fuel filter, but we replaced the filter multiple times to no avail. We banged our heads against the wall for a couple days, then finally we got down to tracing and disassembling the entire fuel supply line to look for a restriction somewhere and that's when we found the hidden second filter. Obviously nobody (including the owner) knew it was there and it had not been replaced in years, maybe ever... Changed it and the truck ran like a freight train.

Ever since then I have had a kind of fixation on always keeping all diesel fuel filters located under the hood in plain sight. However, you're talking about putting a filter in an easy-to-find place where there was already a stock filter located, and anyway you're going to be the one working on it and you'll know the filter is there regardless, so no doubt you'll be fine whichever way you go.

On the wagon I converted last year, I was able to use a regular harness connection at one of the main harness multi-connectors on the drivers side of the engine bay to power the IP and do most everything else, including starter connection, alternator, tach, etc. I think the only separate wire I ended up having to run was for the glow plug light on the dash. My vehicle was a slightly different configuration from yours (1986 740T) but originally had the same B230FT LH2.2 setup so might be similar enough. I know I wrote down what I connected to what at the time so I'll take a look at my notes and see if I can post a chart...

Unfortunately I don't have any good pictures of wiring and fuel system conversion steps but I put a selection of pictures from my swap process up in a thread here in case any prove useful to you: http://www.d24t.com/showthread.php?t=715

Hope it turns out well, good luck and ask any questions that may come up, I went down this same road not too long ago so I might remember some answers that could save some work!

[bigbillyboy11]

Hey v8volvo -
I checked out the link with your swap, and oddly enough, I was driving through seattle last year and say your car. It was the "D24T" plate that caught my eye and then I noticed it was in a gasser body. Wanted to flag you over and ask you a bunch of questions, but it was in the middle of I-5.

Small world
Jason

[v8volvo]

Yeah, that would have been me. I liked to watch people trying to figure out what that plate meant when they were driving behind the car.... one time on a long trip, I pulled off the highway at a rest area and another car pulled in behind me, rolled down the window, and asked what the hell the plate meant... they had been driving behind me for the last 20 minutes trying to figure it out! Either you know it or you don't... You were probably one of the few people who saw it on the road and actually knew what it was.

Too bad we were not able to link up at that time, but I know I did write down my electrical connections somewhere, I'll see if I can track those down this weekend. On mine rather than cutting wires, I left the diesel engine harness alone, opened up the multi-connector for the body harness on the drivers side inner fender, and reconfigured the pins in the connector so that it had the right wires in the right places to just plug right into the diesel harness. Easy to do once I figured out where everything needed to be, and made it look more or less stock which is what I was going for. The gasser has a lot more wires overall than the diesel of course, because of the ignition and injection systems, but there are only 6 or so IIRC that are crucial, the rest you can just eliminate.

George