ConversionsxxDiesel ConversionsxxCummins Conversions

Updated November 2008:

We have now have a sample estimate of a typical FJ80 conversion.  Click here to see the spread sheet.

We have now completed over 40 Cummins 4BT conversions to date in 40, 55, 60, and 80 series Land Cruisers.  Currently there is a wait for these conversions.  However, feel free to give us a ring if you have questions and want to get on the list.  Please, serious inquiries only.

We have been reusing the stock A/C systems, retrofitted to the 4BTs, and have retrofitted aftermarket cruise control systems to work with factory systems for 80 series Land Cruisers so there is no loss of functionality when installing these motors. 

If you are in the market for a 4BT swap, pretty much any 4BT can be modified to have an intercooler of some type, and regular 105 hp 4BTs can be increased to 120 hp or more powerful. 

Due to the rising cost of used 4BTs and the all of the unknowns regarding the condition of used, commercial, fleet maintained, diesel engines, Proffitt's Cruisers no longer installs used 4BTs or 4BTAs, or if you would like us to install a used engine, we take no responsibility for their performance at all.   Rebuilt Cummins diesel engines are available from Cummins, and we will still gladly perform conversions using them exclusively.  We apologize for the inconvience.

   Thank you,
    The staff at Proffitt's Cruisers
 

General Info:
One of the most popular diesel options has been the Cummins 4BT conversion.  

The 4BT makes a mild 105 hp but a whopping 265 ft/lbs of torque and even at this stock rating, this diesel powers even a large, sprung over or tall 80-series Land Cruiser wagons with larger tires very well.  That said, with the simple turn of some screws, it can easily make over 160 hp and over 400 ft/lbs of torque, and deliver just as much power as the early Dodge Cummins 6 cyl pickup-truck diesels, but with some loss of mileage and some slightly increased noise.  Quoting Enzo Ferrari, "horsepower sells cars, torque wins races."  This 4 cyl engine delivers more torque than most V8s and this engine will literally idle over anything, which also reduces the need for deep gearing for trucks that are offroaded.

In most cases, at least 4" of lift is required to fit the engine in as it is deep.  A five speed manual or overdrive-automatic transmission is required to achieve highway speeds and maximum fuel economy for street driven rigs.  Approximate fuel mileage is in the mid to low 20s (though we have had some reports of as high as 27 mpg when driven cautiously and/or on rigs with 33" tires or smaller).  Many aftermarket upgrades are also available for this engine as they use many of the same parts as the Dodge Cummins 6 cyl engines of the same era.

This is a 4 cylinder, direct-injected turbo diesel.  At their stock rating, they produces about the same amount of noise as a "generation 1" Dodge Cummins (1989-1993 with the early body style), which is noticable but not massivly overbearing like many of the later Dodges.  We do recommend some noise provisions (good weather stripping and/or soundproofing) for any rig that will be daily-style driven.  Most 4BT's come from Frito-Lay-type P30 bread vans that were converted from gasoline to diesel sometime in the late 80's or early 90's by Cummins under their "Cummins Repower Program."  There are no other major sources for these engines other than industrial stationary or tractor applications and these will not work in an automotive application.  Because of this, 4BT's are somewhat hard to find and most costs as somewhat expensive at $2500-$3500 for the used engine so you need to decide if it is worth it versus a later fuel-injected Chevy V8 that offers gas mileage in the high teens or low 20's.  We have had some luck finding these used for you but this is not always the case.  Most have a Chevy or Ford bolt pattern on the rear, which can be easily interchanged, making them somewhat easy to adapt to many transmissions.   In general, overall fuel savings does not pay for itself with these conversions; most people convert for the unique aspects of the conversion and sometimes to run alternative fuels suchas biodiesel fuel.  We can and have also retrofitted heated-fuel fuel systems for vegetable oil or winter B100 biodiesel blends.  Many of our customers have had excellent luck running biodiesel fuel in our 4BT conversions.
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Some general explanations & pics:
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Recent conversions, June '07:
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