i have aquired a 1979 XJ12-C. it is restorable and in decent condition but the engine caught fire in 1983 and the owner ditched the v12 and now has a chevy 350 in it which i understand is a common conversion but with the rarity of this model it seems horrific that it doesnt have a jag engine. Is it worth trying to put a jag v12 in it or is the value lost no matter what i do?

 

1976, not 1979

 

Have you researched market value on the car to begin with?

I haven't looked at values recently but my impression is that only the impeccable condition "C" cars come close to bringing enough money to justify restoration from a purely finanical standpoint.

If you're determined to spend umpteen thousands to actually restore the car then, yes, I would convert back to the Jaguar engine.

If you plan on just keeping the car in "decent" condition or "driver" condition, I don't think the value would be much, if any, higher with the V12 engine installed.

Of course, if you simply want the V12 engine back in there on general principles, nobody will stop you :-). Unless it'll be DIY labor, though, I'll bet you're looking at a big pile of money to return everything back to true original configuration....and probably lots of time gathering up all the correct parts, too.

Just my two cents. Others will chime in.

Cheers
DD

 

Good questions. You can find pristine or very good condition v12 coupes on ebay once in awhile. They sell for some good money but I don't think you would recover your costs of replacing the motor. There are so many parts discarded during a Chevy conversion that you would need a complete car to do a transfer properly. So you'd be destroying a good car to make a good car...maybe. You could find a Series 2 Sedan or XJS V12 a doner for a reasonable price and use that. I'm no fan of the V12...They are underpowered, overweight, over complicated and guzzle petrol at an impressive rate. The V12's are an engineering marvel or catastrophe depending on whether yours in running well or not.

Another good option is to use a V12 and transmission from a later car. This would probably be considered acceptable by the Jaguar faithful because it's been done and done well by Fiboy. I purchased a 1994 6.0 XJ12 and planned on swapping the drive train into my V12 coupe but it wasn't as smooth or as powerful I expected and it went through petrol at an alarming rate so I wasn't motivated to do the swap.

Chevy conversions can be horrific if they are done poorly. If done right with a 5 speed or with a 700R4 they are a dream. I'm a conversion fan. I've done two. I removed a v12 from my coupe that had water in the oil. No regrets and it was an easy decision for me after driving the V12 compared to the Chevy conversion I already had.

Most people are lured in by the romance of the V12. I get it...Farrari's got them E Types have them but there are many design issues with the Jag v12...the one that scars me the most is that engine fires are common on the early cars. The distributor is lower than fuel lines so if one of the 30 fuel line hose clamps starts leaking fuel the vapor and fuel collect in the low spot which just happens to be sparking. Not good! Basic maintenance is difficult. Reliability is questionable. Parts are expensive. The v12 is so heavy it masks the awesome handling and braking characteristics of the chassis. The V12 engine and trans easily 300lbs heavier.

I think if you want one with a v12 then sell yours buy the best one you can afford. In the long run it will be a better value and worth more to the next person who's looking for an original V12 installed at the factory. As for future value of the V12 coupes there is no way to know. They are certainly worth more now than they were a few years ago. Chances are their value will go up or hold on because they are scarce.