FJ40 Land Cruiser 6.2 Diesel Conversion by Aaron Leach ©Copy Right 1997

Plenty of power, and great fuel mileage, that is everyone's dream when thinking about an engine to be used in a special project. At least, that is what I was thinking about. I looked at the Chevy 350 because this engine is the most popular conversion in the FJ40, but it does not do that well in fuel mileage. Eventually, talk turned to the 6.2 diesel engine. This engine would provide more than adequate power, and deliver excellent fuel economy. But, would this fit into my FJ40?

After talking to a few mechanics, I found that the 6.2 and the small block Chevy share the same engine mounts. They also share the same bell housing bolt pattern. Which means, I could use and Chevrolet or GMC transmission and use any conversion kit available for the small block Chevy. All this information led me to install a 6.2 diesel engine into my Land Cruiser.

Getting Your Engine

The first thing to do was acquire an engine. When looking for a 6.2, make sure that it has everything on it: brackets, flexplate or flywheel, torque convertor, air cleaner, starter supports, fan, etc. Even though the 6.2 shares some commonality with the small block Chevy, it does not share everything. The more accessory components you get with the engine, the better off you will be. Plus, it will save you time and money.

If you are looking to buy a used "running" engine, check the oil pressure and check for excessive amounts of either white or black smoke. Abnormal amounts of either white or black smoke could indicate a problem with the injection system. Most used engines will leak a little oil, but you should specifically check the rear main seal for excessive leaks. Most leaks are not too expensive to repair and the best time to take care of the problem is before you install it in your Land Cruiser. Look at the water pump for evidence of coolant seeping past the front seal. The water pump and the injector pump are a couple of the more time consuming items to replace on the engine because of location. These components are more involved to remove and replace because other engine components need t o be removed just to get to them. Having an experienced GM diesel owner along when looking at a used engine will help determine if the one you are looking at runs normally.

Conversion Details

I bought the Chevy engine mounting kit and TH350 transmission kit for the Toyota three speed transfer case from Advanced Adapters. I made all modifications to the transmission and t-case required in the instructions, and then bolted it all up to the engine. I then began the process of fitting the engine into the FJ40's chassis. I used the same directions that comes with the kit for the small block 350. I positioned the 6.2 so that it was about three inches from the radiator, and adjusted the center line of the engine at about twelve inches from the left inside frame rail. This measurement was the same as for the small block Chevy engine. One thing to remember is that the 6.2 is physically larger than the 350. I had to remove the stock steering box to make room for the engine(Fig. 2). This did not affect my plans since I planned to install a Saginaw steering assembly anyway. Because of the width of the engine, I lengthened the steering shaft an extra eighteen inches. I also cut the engine mount down(Fig.3) about an inch and a half, so that the steering shaft and u-joint would have enough room to clear the exhaust manifold. I also removed a few unnecessary components like the cruise control mechanism, and the part of the air inlet system. These mods allowed the stock hood to close properly. Also, the 6.2 engine mounts use a spacer between the engine mount and the block. This spacer is needed for installation.

What You Can Use, and What You Cannot

• The 6.2 will accept all GMC & Chevy transmissions: TH350, TH400, 700R4, SM420, SM465, etc.
• You cannot use a gas engine torque convertor, you have to use a diesel one.
• You cannot use a gas engine flex plate or flywheel. The diesel's is balanced. Also, when using a flex plate, there are two kinds, a lock-up type, and a non lock-up type. Each uses a different torque convertor.
• You will not be able to use the stock steering on the FJ40. You will have to install a Saginaw steering system.
• The injector pump and injectors use a fuel return system. You will need to run a return line to the fuel tank. In my FJ40, there was a line that ran from the evaporative box(located near the gas filler neck)under the floor to the engine side. I used this to run my return line.
• Diesels use their own starters. Gas engine starters are not powerful enough
• Diesels use their own engine cooling fan.
• One battery will probably fit, but two might be difficult. You can get a box made that fits behind your seat that will hold two batteries. This might be the only place to put two batteries.
• When installing the 6.2, make sure that you use the eighth inch spacer used between the engine mount and the block. This helps in the fit up process.
• A suspension lift will ease installation because the drive line might hit the oil pan. Also, you may need to experiment with a smaller diameter drive line depending on what transmission you use, and how much lift you have.
• The length of the engine/transmission/t-case assembly necessitates a rather short dive line. My rear drive line will only be about twelve inches long. The transmission/transfer case kits for the 700R4 and the TH400 are quite a bit longer. With these transmissions, you might have drive line problems.
• A diesel fuel filter assembly that also contains a water separator is required.
• Typical 6.2 RPM operating range is between 1500 and 3000 RPM's and the best fuel economy will occur at 1800-2000 RPM's. An overdrive transmission, or larger diameter tires will help increase fuel mileage at cruise speeds. But if you want a serious off road machine, stay with the lower gears. To help you best judge your RPM's, you can install a diesel tachometer.

Wiring the Engine Up

Electrical control for the 6.2 diesel is pretty simple. First of all, the wires going t o the starter are the same as they are going on gas engines. Secondly, the ignition wire that used to go to the coil on the original engine, will now operate the fuel shut-off solenoid in the injection pump. The fuel shut-off connection is the front most terminal. The other terminal on the injector pump is the HPCA (Housing Pressure Cold Advance) terminal. This terminal should be connected to the temp. switch on the lower passenger side head and then to an ignition switched 12 volt source. This temperature switch and the injection pump solenoid will advance the injection timing approximately 3-5 degrees during engine warm up.

Since I did not have an operating glow plug controller system, I ran a wire to a push button switch, then to a 10 second relay, then from there to two 70 amp relays, one for each bank of glow plugs. When I push the button, the power turns on for ten seconds to heat the glow plugs.

You can also hook this up to the ignition source. The only difference is that the ignition switch would take the place of the push button switch. This system would be relatively safe when using the AC-11G glow plugs. It is recommended if you do not use the stock controller system for the glow plugs, that you switch to these glow plugs. The system that I am using might tax the temperature range of the standard variety glow plugs intended for the 6.2.

Conclusion

On and off road, you will love the power and economy of the 6.2 diesel engine. I have talked to people who have installed this engine into other vehicles, and they are getting 28 miles to the gallon, and still have the power there to provide towing ability. It is the kind of engine that will give comfort, refinement, and reliability. All in all, you will enjoy the 6.2 diesel engine.

Parts used in the conversion:

Advanced Adapters engine mount kit for the 350 Chevy

Advanced Adapters TH350 kit to three speed transfer case

smaller diameter shaft for the drive line

lengthened steering shaft

Volkswagen water/fuel separator

diesel tachometer( Auto Meter part #2888)

three inch diameter exhaust tubing

Parts used in the electrical setup:

2 70 amp relays

1 10 amp 10 second timer relay

tons of wire

a few electrical connectors

one push button switch

light

Sources

Advanced Adapters

PO. Box 247

Paso Robles CA. 93447

Telephone

805-238-7000

FAX

805-238-4201

Jim Bigley

Editor

"The 6.2/6.5 Diesel Page"

http://www.62-65-diesel.com

Andrew Freeth

Chiltern Automotive Ltd.

Email: Andrew@chinnor.demon.co.uk