The 3B is a 4 cyl diesel engine, inline fuel pump, 100% mechanical other than EDIC control, and glow plugs and related accessories.

The 3B puts out about 92 hp and about 150-160 ft/lbs of torque  It has a very high rev scale compared to a 2F Gas engine, it actually redlines higher than a 2F engine.  Because it is not turbo charged, it is easily affected by altitude, likewise when upgrading to larger tires, you must pay very close attention to axle gearing, like with all diesels.

They were available in North America from 1981 to 1985, in Canada, in 40, 60, and 70 series models.  They are found with either a 5 speed manual transmission (H55F) or 4 Speed H42, the same transmission found in US Land Cruisers.

The 13B-T is the non-USA factory turbo charged version with major differences being direct injection and accompanying parts.  It shares the same block but different head.  Otherwise it has the same bolt pattern as the 3B.  It was never available in the USA, and was available in Land Cruiser from Africa, South America and in many other countries.  13B-Ts can be bolted to later 3B bellhousings but not to early "B" bellhousings from Canadian Cruisers from 1978-1980.

Overall, all B series engines are rougher and a little more rattly because they are 4 cyl.  3B's are found in Canada in three variations, 3B-I which ran all through normal production, and a very rare 3B-II that was introduced in 1987.  But since Canada's normal use of 3Bs was replaced in 1986 with the 2H diesel engine, 3B-II models are found in mine trucks, and possibly in some later BJ-70s which were available in Canada in 1986 and 1987.

Supposedly 3B-II are more desirable because they are easier to modify for turbo charging and are generally a little more advanced mechanically.  All "B" series engines are based on the original B diesel engine.

Adding a turbo is a wonderful addition, especially because the 3B came with piston skirt cooling. 

Some other helpful stats from Corrections to Dieselology:

The 3B underwent some changes over the years, however they are all called 3Bs, as I mentioned before.  The 3B-II has a rotary pump and was not sold in Canada, other then for mine use AFAIK.  The two pictures show some of the changes.  The oily engine is out of a 1983BJ60.  The alternator bracket is a 2-bolt design, the oil filter points down, and the rocker assembly has 3 supports.  The other picture is from a post 1985 truck (unknown year-mine truck 3B) and has 5 supports for the rocker assembly, the oil filter points up, and the alternator bracket has three bolts.  Both are 3B’s.

Click here for photo 1
Click here for photo 2
 

Here is a pic of a 13B-T compliments of Greg Bowie:
 

Compliments of Peter Straub
First of all, generally accepted specs on the 3B is 92hp and 145lb-feet, not 97/160.  In your article you discuss the early/late 3B-I and 3B-II. In Canada, we never got the 3B-II. The 3B-II had a rotory injection pump, along with a few other differences.  In Canada, we got the the B series diesel in 1978-1980 in 24V BJ40's. The 3B appeared in 81 in BJ42s (24V), and BJ60's (12V), and BJ70's (12V in 1985, 24V in 86-87). In 8/85, the 3B engine did have a change - went to a 5 bearing cam, aluminum bellhousing, and some other minor changes, although it is not considered a 3B-II. I think only the 86 BJ70's got this very rare engine.

Peter is 100% right about this.  I was aware that there are two "versions" of the 3B, based on some US sources I was mislead to believe the second version of the 3B-I was the 3B-II.

Some other points... The F and H bell housings are shorter, not longer, as the B input shaft is longer and 23 spline, where the F/H input shaft is shorter and 10 splined.

Also, Canada never had a factory H41 equiped vehicle. All 4 speeds in BJ42's were H42's. I would also challenge the statement 'on a 3B-I you have to make fairly involved oil passage changes to turbo charge it'. Having turbo charged an '81 3B with an AXT kit, and adapted a custom wrecking yard turbo to another '81 3B, I am uncertain of what you speak.

This also from a US source who spoke of this problem...

Peter Straub

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From Greg Bowie:

The most reliable stats place the 3B at 90ish HP at 3500 RPM and 160ish Torque at 2200 rpm. 

They were available in North America (Canada only) from 1981 to 1987.  1981 to 1984 in the BJ42 (24V), 1985 BJ70 (12V), 1986 to 1987 BJ70 (24V), 1981 to 1985 in the BJ60 (12V).  The “B” series engine was available in Canada from 1978 to 1980 in the BJ40. 

The BJ60 and BJ42 from 1981-1982 came with the H42 (Not the H41).  The BJ40 was all H42.  In 1983 all LC’s to Canada came with the H55F.  Canada never got the H41’s. 

The original “B” engine in the 40’s was an inline 6-cylinder gas engine; hence the first Land Cruiser’s that had the “B” designation were gasoline, not diesel.  The engine changed to the “F” motor (gasoline), and I have no idea the year that happened.

The “B” diesel engine may be what you are referring to when you say 3B-1?  As mentioned above the “B” engine came in the 1978-1980 BJ40’s.  When the 3B became available in 1981, the designation was changed to BJ42.  There were some other changes as well, like the 1981 and up FJ40s (fuel tank, big eye spring hangers, fuel tank under the vehicle, to name a few). 

The 3B underwent a change in the 1985 model year (listed 10/1984 I think), in that the rocker assembly went from 3 supports to 5.  There was not engine designation change that I know of.  There may be, in some stats somewhere, the block numbers and some change there…but a 1981 3B and a 1987 3B are both called 3B’s. 

There is a 3B-II, and I believe that came out in late 1987.  We did not see it on the street in Canada.  I believe the mines got 3B-II’ for a while.  The biggest change I know of is the 3B always maintained an in-line injection pump, and the 3B-II was a rotary injection pump.