Fix Your Jaguar XJS V12 By Adding Diesel: Cummins Diesel Swap

By - Jaguar XJS Cummins Diesel Swap

The Jaguar XJ-S V12 is a cherished classic of the brand. One forum user has ripped out its old, tired heart and is swapping in a Cummins diesel motor.

The year is 1983 and the Jaguar XJ-S V12 is the top performance offering on sale. The 5.3 liter V12 powering the luxury coupe offers 265 horsepower and uses a four-speed automatic transmission. The grand touring coupe is built to cross the country at high speed, so you don’t miss your next tennis match. The leather lined interior provides all the comfort and modern conveniences in 1983. So, now take yourself back to the present and lets examine just how you fix an engine-less V12 XJ-S in your backyard?

Forum user Pud, was facing just such a dilemma which a newly purchased 1983 XJ-S shell in his yard. He could source a used V12 and transmission from a junkyard or buy a running XJ-S to swap over the parts needed. On the other hand he could look at the tried and true small block Chevy swap. If he wanted something different he could look at a modern supercharged V6 from a crashed F-Type and build a screamer. Pud instead chose to go a different route, dare I say, a stinkier one.

He found a first generation inline-6 Cummins turbo diesel motor out of a bread truck. He then had to rip it out of the truck and figure out making it run. After stripping and clean up the top of Cummins, it still would not rotate completely. Even though other forum member expressed their doubt on whether the 1000 pound diesel motor would work. Then, they were questioning his sanity for choosing such a odd swap, undeterred Pud continues to work on the motor. He is currently test fitting the Cummins motor into his XJ-S and is very happy with the progress of the project. So, lets give him some support and check out the man’s oddball swap.

ALSO SEE: Jaguar Quietly Debuts Diesel Engine

Patrick Stevenson is an Internet Brands' contributor to 6SpeedOnline, Honda-Tech, Corvette Forums,, and MBworld. He is also a host on The Motor Affair Podcast.

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