Buying new xke v12 engine

I recently bought a beautiful1974 Series 3 XKE with a Chevy V-8 Tuned-Port EFI Engine. The Transmission needs to be rebuilt or replaced, so both will be pulled. Accordingly, I am considring installing a new, practical, dependable 420 HP EFI V-8 Chevy ZZ6 engine, or spending more to maintain a new, fussy, problematic, beautiful V-12 which naturally increases the Jag’s Classic value. If you decided one way and regret it, or if you are very glad you did decide on a similar touring engine option, please comment.

If that is how you think…. Do you deserve a V12?

Now, now. This is the Lumps category. If you don’t like it, perhaps not follow this category?



Perhaps post a question on the e type forum asking about if owners have found the v 12 problematic. My choice for an e type would always be to go back to an original type engine if at all possible. I doubt if you would regret it.

I think you need to think more about what YOU want from the car. Why did you buy it in the first place - what attracted you to the car? What do you want from an old car? Do you get your enjoyment from doing big projects? Small projects? Would you rather drive than work on it, or the other way around? Did you buy it to enjoy for a long time, or do you like to flip through cars? Did you buy it for an investment, and if so short or long term?

There isn’t a wrong answer. Everyone has their own different ways of enjoying the hobby, and it could even change from day to day. Some days you might simply want to get in and turn the key and go for a drive, while others you may just want to spend doing something in the garage.

Is there something inherently wrong with the current V8 that makes you consider the ZZ6? Could you just keep it and modify it? Again, it all depends on what is going to give you enjoyment.

Regarding replacing it with a V12 to “naturally increase the….classic value”, that’s going to probably take a lot more work and it is a crap shoot if you’d recoup that investment. A new V12 isn’t going to check the boxes for originality, and there is a lot more involved with getting it back to original shape.

Just figure out what is going to make you love the car, and go that way. You’ve got a lump, and it can be a lot of fun without worrying about its enhancing its classic value. Worrying about that is sort of like not sleeping with your girlfriend to save her for the next guy.


He can do what he wants Gunnar.

If he believes that a V12 is impractical, not dependable, fussy and problematic it doesn’t help that he likes how it looks or that the resale value might go up.

Should I buy the bland flat expensive Cola or the tasty fresh good value Pepsi? You tell me what I want!

I’m just saying the V12 is an excellent smooth engine and don’t think it is fussy in good condition. Like most engines.

Where would one find a “new” Jaguar V12 ?

Hello purists! He bought the car with a different engine in it. Why? My take is that he was blown away by the looks, and just impulsively bought the car because he could. I too would have done the same thing. I would check out the workmanship of the project and make any changes or improvements and just drive it a while and see how I liked the engine that is already in place. V-12 fever? No problem. Just buy an XJS for peanuts and pull and install.

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It’s pretty hard to argue with a good old chevy v8 if you’re being objective. I’ve owned Alfa Romeo’s, BMW’s, Mercedes, from all over the spectrum and the world is full of beautiful motors (especially the Busso V6) but it’s mighty hard to argue with the economy, reliability, ease (or lack) of service and power output of a good ole cheby v8. A v12, any v12, is not going to be as cheap or simple to buy or maintain or operate as an old domestic V8. That does not mean the jag or any other v12 is bad, it’s a beautiful motor as the OP said and let’s face it, these are not practical cars that are the best at anything, but they are beautiful, so we love them. But the proof is in the proverbial pudding for an ole small block. While I don’t personally think the Jaguar v12 is any more problematic or flawed than it should be for what it is and when it came from (and a lot of its issues are from people not knowing the quirks oddities and necessities of its care and maintenance), there are a scarce few that pull any kind of real mileage for a reason(s). If you want to drive the car you’re better off with a good v8 if you’re faced with needing a replacement. Otherwise, the v12’s are way more interesting to look at and way more likely to give you something to fiddle with on the weekends. As for myself I drive cars, a lot. 240K miles on my XJS says the vee-eight has plenty of merit. And it’s not like 90% of people are pulling perfectly good v12’s out to stab in a v8. This whole thing happened because of an abundance of perfectly lovely cars with crapped out original engines (which were therefore cheap since it cost a bloody fortune to repair them that nobody was going to pay) that were otherwise going to be scrapped and parted out. Better on the road with an alternate engine than no longer existing I say.

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As to looks. check out a well dressed SBC.
Carb or EFI.

Not that I do not admire the v12. Because, I sure do.

Owned a v12 powered car. for a very short time. A 34 packard four door. A college student at the time. worked at a gas station. got a discunt on then cheap gas. still too much for my “budget”.


I wholeheartedly agree… I’m not a huge fan of V8s, but if I had an XJS, or a Jag sedan with a V12 that was crapped out, I wouldn’t spend the money to fix it.


I now have ten years and ca 45.000kms (ca 30.000 miles) behind me on an unrestored, unmodified, over 50 year old original V12 OTS. (Before that 16 years and 67.000kms on a self-restored S1 4.2 2+2.)

The only technical problems have been the earth connection to the fuel pump, fixed in 2013/14, the LH side fan motor running out of a brush in 2017 and the original OPUS MK2 ignition amplifier dying in late 2018. After it was rebuilt, no issues at all.

Running fine (& fast) under all kinds of conditions across the continent and over the Alps several times, Le Mans Classic in France and Festival of Speed in England, and a Jaguar meeting in Vadstena, Sweden in 2018 and the Goodwood Revival in Chichester, England this fall.

A PO had removed the vacuum lines and olugged the carb by-passes and dizzy retard, which resulted in slightly uneven running and lack of power when cold, but that was also rebuilt and now works perfectly as designed originally. YMMV.



That problem could easily be solved with a nice straight six :slight_smile:



after all, this is the lump category: try this:

…and it‘s brand new straight out of the box.


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SO, you already have a tpi chevy. Is anything wrong with it? If you’re just looking for brutal power a blueprint 383 will get you over 400hp. Add an edelbrock pro-flo4 or tweak your tpi. The tpi or pro-flo4 xt will have good hood clearance. Rebuild the transmission and you’ll be passing off the purists with functional ac and a car that starts by just turning the key.