1948 Jaguar MK IV DHC

I have found a MK IV with a replacement engine (#SL3036). Where can I find information about that engine? I want to verify it is identical to the original engine (#SL2562) in the car if I possible.

Hello John,

The engine prefix number for a 3.5 Litre MKIV is a single “S”. Do you have the Chassis & Body Numbers for the car? A few photo’s never hurt to help identify things.

The last engine number was S4455 so I’m guessing that your engine S3036 is probably from early to mid 1948. My 1948 3.5 has the original engine S3067 and was built 3 June 1948.

Others will know a lot more than me, I’m sure but it’s hopefully a start.


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Actually the number on the engine is SL3046 and the engine number on the copper plate on the firewall is SL2462. The chassis number is 637012 and the body number is C1045 or C1015 (hard to tell). So presumably the engine is newer than the car but is it a correct 3.5 liter?

Brain engaged now! SL is for Left Hand Drive. :roll_eyes:

There is quite a lot of information about your car on Saloon Data.com

Just put in your Chassis Number and there is your lovely Green DHC.

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It is definitely a correct 3.5 L engine. All that information (and numerous photo’s) is on the Saloon Data website, including previous owners, restoration etc.

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Thanks. Will take a look. First couple tries I could not find any reference to the replacement engine (number SL3046) in my MK IV so the car in which it was originally installed might have been destroyed (?)

Or it was one of the swop engines mentioned on other posts where dealers replaced damaged engines with a swop for a reconditioned one

As Richard said, Jaguar seems to have offered a reconditioned engine and gearbox as a ‘swap’ apparently to hasten the ‘turn-around’ time. Some cars suffered a fatal failure with a broken con-rod punching a hole in the block and so a replacement engine would have been fitted. Worn out engines seemed to have been replaced with the reconditioned engine and gearbox, so I am guessing that this is probably what happened to your car. It was not uncommon, in that era, for a MKIV to be fitted with an engine from a MKV as they were basically the same engine. I have a MKV which is fitted with an engine from a MKIV, so I guess you will understand the haphazard process of the time. You are fortunate to have a MKIV motor from a car that is not much older than the unit it replaced. All good fun!


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Timothy 2963
OK thanks. .

mark_iv_and_v_chassis_numbers.pdf (198.9 KB)
Info in the attached file should help. Good luck!

Chassis+engine Mark IV DHC.2

Also have a look at these attached documents. I don’t see your engine on them, but they give you an idea of possible dates.

Got it. Thanks.

Thanks. Helpful. Clearly it is 1948 engine (SL3036) but I suspect that fact that no record exists means it was a swap and/or the car in which it was originally installed may have been destroyed.


AFAIK didn’t even need to be damaged, normal decarbonising, replacing bearings etc the customer would not wait.

So for instance at Hornburg, LA it was perfectly normal to swap a rebuilt engine whenever necessary.

My 1950 MKV DHC #647194 that originally had a MKV engine Z2453 has had engine #SL2199 for at least 50 years, very likely even longer.

SL2199 was made in the sumner if 1947 when LHD production first began. Your car (do you have a JHT certificate) was likely made in the fall of 1947 and the later engine (SL3036) perhaps early 1948.


Hi again,

Are you sure the body number is not C1013? It would be in sequence (not always the case,) on my car’s #647194 data plate looking at the engine number Z2453 the ”3” looks very much like.a ”5” but as it happens to be next to a ”5” it’s easier to see the difference.

Also the ”1” has a long ”hook” so it may look a bit like a ”4” except when you look at a ”4” which can be seen on both my chassis number and original engine number.

Do you have a body tag on the scuttle with the body number?

Check out a few data plates, I think the data plate on 637014 shows that that was the car that had/had body nr C1015.

IMO the £40 GBP / $60 USD is well spent to get the verification, original colours, bulld date, dispatch date and original main distributor. I would bet it was shipped to Hornburg.




Maybe in Australia, but for instance my car, and some other MKV’s and MKIV’s from California I have seen have all had the original gearbox. Mine still does (#JH3529), only the engine had been swapped, most likely already in the 1950’s, but unfortunately with my car and many other West coast cars nothing is known between delivery to Hornburg and 1976.



Ok I see now, part of the problem is that the data plate on your car is not original, it’s a repro I have as well.

So someone had stamped the numbers on it, not factory.

There seems to be a JDHT certificate too, but it’s unreadable on www.saloondata.com

Your engine is correct type, so it has been swapped at some point, no problem, but the other data would be interesting to know, the main distributor, build date etc. If you have those please post and add them.


Welcome John. As you can see we have a lot of enthusiasm for these cars.
SL prefix does indeed indicate the engine was originally set up for Left Hand Drive.
Since the Mark IV and all previous models had been designed for Right Hand Drive only, when they realized the American market was the bright future and decided to make Left Handers starting about 1948 or maybe the tail end of '47, there were some special modifications required to make everything fit around the steering column.
Air cleaners and the intake plenum moved from downwards to up top. The oil filter on the left side became a remote filter on the rear brace. The clutch, brake and accelerator linkages all were new for LHD, and I understand the clutch especially was a Rube Goldberg (UK = Heath Robinson) affair.
And of course the steering box was opposite hand.
The next model the Mark V was specifically designed to be made in both LHD and RHD.
All fun stuff.
No obscure Jaguar question is too trivial for this group. :grin:


Yes indeed. Quite amazed and much appreciate the prompt responses, knowledge shared and helpful advice.

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Is it now your car or are you interested in buying the car?