RobotMoose

iTrader: (1)

I had a kind of monkey-touch-monolith moment the other night, and I've been exploring the potential of swapping over to a 4BT, since my 22R is already on its way out the door. I'd like to hear the thoughts of other folks on the matter, but please give my ideas a once-over beforehand.

There are a few diesel swap options out there for a Toyota pickup: 4BT, B3.3, 2LII-T, 1KZ-T (Unobtanium), 3L w/ 2L-T turbo (Unobtanium) OM617 or VW Diesel.
Out of these options, the 4BT makes the most sense since it had a broad adapter support base, Cummins has exceptional support and will drop-ship replacement parts to you on a phone call. Almost any basic diesel shop will have parts. Finally, the 4BT is pretty much too stupid to die.

The pros of the swap:
- It would almost match my new motor budget, dollar-for-dollar.
- Serviceability
- No EFI or carburetor
- Simple electronics:
starter exciter, alternator, 12V to injection pump, gauges.
- Broad support base
- Improved overall economy and power
- Extreme dependability.
- Only about 1.5" longer than a 22R, surprisingly.
The cons of the swap:
- Weight
- Everything has to be fabricated
- These things ride rough
- Unforseen wear by neglectful previous owners
- Basically stacking adapters on adapters
- I've sunk a fair amount of money into my L52 and now have to abandon it.

This is my prospective setup:
Driveline:
A 4BT from a step van that had been mated to a GM manual transmission mated to an R151 via an AA GM-to-AX15 bellhousing and an RF1A T-case with Marlin gears and an adapter.
--I've read that people have swapped these engines onto AX15s before and they seem to hold up as long as you don't shock it.
Brakes:
I think I'd rather run the vacuum pump off the alternator over hydroboost, It means less headaches in the long run.
Clutch:
The AA kit comes with most of the hardware and suggestions of other pieces. I may have to swap over to a 60-series master for additional throw.
Wiring:
Once the engine's in, I think I'll just systematically pick through the harness and bundle and stow the old connectors and legs, leaving the option for a potential future swap back available. This means I'd probably run most of the body harness as-is for lights and wire in my own gauges and legs for glowplugs and IP.
Other:
Exhaust is passenger's side drop, so there may be clearance issues with the T-Case
Since my truck is carbureted there's nothing in the tank causing obstruction of the fuel flow, so fuel lines would mean re-routing with viton and most likely pulling the stock hard lines. I believe the IP pumps its own fuel.
I've heard that the 22R radiator keeps these engines sufficiently cool, but a V6 radiator swap is an option. I already have a small "pusher" fan routed as a helper for low-speed travel, and I'll probably swap in an additional larger "puller" fan to help cool the engine. From what I've read, the 4BT is a pretty cold-blooded motor.
Upgrade the governor spring for a 3200 RPM redline, which gives the overall truck better road manners.
I'll probably keep my stock 4.11 diffs, but upgrade my inners and birfs for extra protection.
I need to find what my options are for a P/S pump and an A/C pump that might work for my truck.

Terrys87

iTrader: (1)

I too would like to do a diesel someday. From my studies, the 4Bt is pushing the limits for a solid axle truck and is not recommended for an IFS truck due to weight. You dont say which truck you are going to be putting it in. From what I have read, they are a great engine, just to heavy.

RobotMoose

iTrader: (1)

Oh, good catch!
It's an 83, solid front axle. I think with a lift, clearance shouldn't be an issue.

usmma2013

I hope to not discourage you (I'd like to see some more do this), but very few actually do this swap for several reasons.

With the 4BT you'll need to re-gear as well. I'm not an expert on ratios but my '94 has stock gearing and my swapped OM617 turns 3,000 rpm on the highway @ 70 mph. Even with a different spring I do not think a 4BT would be happy at that rpm.

As far as Terrys87 comment, he is not referring to clearance but referring to the weight of the engine (nearly 800 lbs). That is more than twice the weight of the heaviest engine Toyota put in these trucks, the 3VZE weighs in around 350-360. To do a legitimate swap, the frame, suspension, and steering must be strengthened which involves far more work than the VW TDI or Mercedes swaps.

I would do my 617 swap again, the power delivery and redline was tailored to move a heavy car in a well-rounded fashion and works just as well moving a pickup. If I had to pick another, I would hunt far and wide for a half cut with a 1KZ-T.

dropzone

iTrader: (6)

Yep the weight of the 4BT has been a deal breaker for a lot of people.

Dale Johnston

I would really like to hear from someone who has done this swap. I first had the idea after I rebuilt a 4BT in a Case 580 super K backhoe. If I remember right the operating range is 1100 - 2250 rpms, so gearing would be an issue, not to mentoring n weight. Does anyone know if higher diff gears would help?

RobotMoose

iTrader: (1)

Thanks for the input, folks!
I think I'll keep going forward with my plans for a freshly-built 22R; the tired old 60-ish HP unit I'm replacing has served me well and faithfully, I'm sure a new one worked over to 100-105 would be a blast.

Maybe later on down the line I can scrounge up a decent-conditioned mechanically-injected 1KZ-T and do the swap then, but for the time-being I'll just run what I've got.

usmma2013

Have you considered an OM617 swap? Engines are plentiful, easy to work on, and parts are cheap. I'm quite pleased with mine, and the only two parts of my swap which were time consuming were hassling with moving the transmission (R series) and modifying the oil pan to clear the IFS - neither of which you'd have to deal with given you had a solid axle and W series trans I assume?

4x4Labs is still producing quality adapters and crank hardware for this swap.

RobotMoose

iTrader: (1)

I have given it some thought, and from what I've read the OM617 is a great upgrade. My concern is space; my first-gen pickup isn't really gifted with a great deal of under hood space and of the two OM617 swaps for this model I've seen, one ended up with the radiator in the bed and the other had to mangle up the front bib in order to fit the radiator inside it.

I love what 4x4Labs is doing, Luke is a good guy with some innovative ideas and his conversion kit is probably one of the best available for the swap.