so i am building a 1964 S type right now and im getting ready to pull the engine, and a few questions have come up in my mind about its size. so it seems the engine in the car has been replaced at some point because the original was shout out (there are literally bullet holes in the inner fender) some time before it came to canada. the badge says 3.4, the previous owner says 3.8, but the stamp on the side of the block say 4.2. though the fuel system seems to still be from a 3.8 as it has the dual su and not the triple. is there any way to know for sure with out just taking off the head and measuring the bore?

 

On my 340 and I am assuming on all Jaguars that have the 3.4 litre block, the displacement is in raised numbers cast right into the block.
This found on the "carburetor" side of the engine.
Isn't it the same for the 4.2 litre as well ?
A mirror and flash light should tell you.

And if you mean stamped or raised letters cast into the block and it they say 4.2, then it's a pretty safe bet that it would be a 4.2 litre engine in there.

EDIT:

Dug a bit and found a photo, I exaggerated the picture so you can just make out the 4.2 Litre numbers just forward of the Jaguar logo.
That's where it will be.

 

with the VIN of the car, you will know what engine it left the factory with, whether a 3.4 liter, or a 3,8 liter, and maybe the compression ratio.
If the Badge says 3.4, it was a 3.4.

The S type never had a factory 4.2 liter, the 420 that came after, and the XJ did, so obviously it was a swap.

go to the S type Register, join the Forum and David Reilly will answer.

by the way, I salvaged many parts from a 1964 S type that I found in the florida jungle.

Jaguar 'S'-type Register

 

yes it has 4.2 in raised lettering on the side of the block.

 

It's a 4.2 litre block then and it has no business being in there, as Jose points out.
Personally if it was my car, I would use it, it's a heavy car, the more displacement the better.

 

Yes, the 4.2 will make a faster S type, not to mention it is the smoother engine of the 3 bores, otherwise it is the same block.

 

Me too. Nothing beats cubic inches.
(Well, someone had to say it!)

 

ya i am certainly not complaining, im not one to turn my nose up at free displacement. though now i will have to find some badging to match it haha

 

A "4.2 S Type".
You'll most likely have the only one.

 

The 420, the last iteration of the Mark 2/S-type bodyshell, did, indeed have the 4.2 litre engine. Actually the smoothest engine of all was the 2.4 litre, but it wasn't powerful enough !!

 

Shame on me _ I forgot about the 420, but it needed the bigger engine _ it was a big car.
The smoothest engine with the Daimler V8, but off course it wasn't a Jag engine.
What size of engine was in the MK X, I think it had the 4.2 in it as well ???

 

well the s type is half 420 so i suppose i can have the engine too haha

 

The 420 was about the same size as the S-type. There is the 420G, the successor to the Mark 10, which had the 4.2, the Mark 10 had the 3.8.

 

It's quite possible the motor let go and they just replaced with the larger capacity one and reused the intake system for cost cutting measures.


If that is the case, might be worth checking the mixtures/air Fuel ratios to make sure its not running too lean, which could damage the motor prematurely. Unless the carbies have already been adjusted accordingly to suit the extra capcity