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Tue Mar 02, 2021 5:28 pm

Acquired a 1978 bus fuel injected engine to go in our 1973 bay window. All the injection stuff, wiring, computer is all there. I want to just transplant it into the 1973 and run it as is. Where would I tap into the existing wire harness or would it be best to re wire the 1973 with an updated new harness? All the existing wiring seems to be in good shape. There are a few wires already cut in the engine compartment. Just ends missing type stuff. Playing with the idea of microsquirt controller may be later but object right now is to just migrate the engine into the bus so we can drive it/work out any other bugs.

Tue Mar 02, 2021 5:44 pm

To use FI you'll need a later fuel tank with a return line fitting, a FI style aircleaner mount and a hole to mount the ECU, all the wiring is independent of the bus harness so that can stay. You'll also need a 76+ 091 transmission, the ratios in the 73 don't work well with a 2.0 and the bellhousing doesn't accommodate the bigger flywheel.

Tue Mar 02, 2021 6:34 pm

Can the flywheel be swapped out or is that a no go? Even as a temporary measure? Or maybe the bell housing swapped? I have 2 different engines. The 78 engine and another one I sourced without any tins, fan, etc. and I’m not sure of the year of it. Bus didn’t have a trans so I found one locally that is a 3 rib.

You’re saying the injection harness is separate? So the ECU just needs juice for that?

I have a couple of tanks that came with the bus. Can a return line be added or are there internal differences in the tanks?

Tue Mar 02, 2021 8:04 pm

Yes, the earlier flywheel will fit the later engine, but the gear ratios in the early trans really leave alot of that 2 liter power on the table, it's kind of a waste. That combo does work well with big mud tires though.

The FI system gets it's power from the ignition wire at the coil and another wire on the starter, the bus body harness is no different than a carb model.

The return line can be added to a carb tank with a bit of work, but the FI one has a special pan in the bottom for the fuel pickup, and the tank likely has to come out if the bus has sat more than a year anyways for a cleaning and vapor line replacement.

Tue Mar 02, 2021 8:48 pm

What's the engine code on your other engine? Look on top of the case below the breather, always under grease it seems. If it is earlier you just may need a set of carbs and some odds and ends and it will match your trans. The tins and fan housing off your 2.0 may interchange, too, depending on what it is.

Did you get that paint shined up yet? Looks like original paint!

Tue Mar 02, 2021 11:16 pm

IIRC you just need to need four wires to do the swap.

The B+, #30 wire
The #15 ignition wire
The #50* wire from the starter solenoid
and
The wire from the double relay to the fuel pump.

The original '73 transmission is fine if you are willing to limit your top speed.
Yes you can swap the flywheels or you can clearance the bellhousing if you can't find a later one. The flywheel, bellhousing, clutch, and starter are essentially a matched set.

You will need the engine to tranny mounting hardware that matches the bellhousing.

You will have to shorten the shift rod if you go to the later transmission as the nose cone is about a 1/2" longer or you can put the earlier nose cone on the later transmission. The later transmission will require clearancing the one cross member slightly.

You will need to decide if you want to use the 72-74 exhaust or the 75-78 exhaust, the 79 exhaust and heads are a set that can't be interchanged with other years.

Yes you will need to a mount for the air cleaner and a way to mount the ECU, and as mentioned you will need a return line setup for the fuel.

All and all it is not a bad swap.

Wed Mar 03, 2021 2:11 am

I have a 2.0 mated to my original transaxle in my 73. I find the gear ratio to work fine.

Wed Mar 03, 2021 6:57 am

Fantastic! I figured I would maybe find a set of 15” wheels and tires to run on it with this engine and trans combo. It has 14” on it now. A taller set up will mellow out the low gears. Did the same on an old Chevy camper special truck we have to get a bit more top end out of it. It will pull a house but with the low gears it at 65 miles an hour it sounded like it was going to blow up till we put a little bigger tire on it. Later on I’ll figure out a different trans for the bus if needed. Priority right now is to get it running to work out the bugs and go through the other systems. Wheel bearings, steering if needed all that stuff. I need to find the transmission mounts and a mustache bar because those are missing. If the wiring is the same for the chassis that’s great. There are a few wires that have been cut in the engine compartment. Those need to be identified and sorted out too. And the guy I bought the engine from cut one of the harnesses for the engine. I have both pieces so I’ll either just put it back together or rewire it.

Wed Mar 03, 2021 2:41 pm

Fuel tank wise I think I'm going to snag an in tank pump from Tanks Inc. and use one of the tanks I have that came with the bus. They have a retrofit in tank set up that has the return and everything plus it will be a lot quieter with the in tank pump. Looks to be a super easy install. Safer too.

Wed Mar 03, 2021 2:58 pm

carguytroy wrote: Fuel tank wise I think I'm going to snag an in tank pump from Tanks Inc. and use one of the tanks I have that came with the bus. They have a retrofit in tank set up that has the return and everything plus it will be a lot quieter with the in tank pump. Looks to be a super easy install. Safer too.

Let us know what you use. An in tank pump with a top outlet seems a whole lot safer than the stock setup which can easily drain out the bottom and quickly drain the entire tank onto the ground should a line fail.

Wed Mar 03, 2021 3:52 pm

Do consider the rather low pressure and flow L-jet runs compared to modern systems, some have had issues with current pumps overwhelming the pressure regulator.