I am not a jag purist but do love the body style and interior coachwork of the convertibles. My favorite is the older xke convertible. Sadly I can not afford my all time favorite car so I bought a 1996 xjs convertible. A low mile (66k) car in excellent condition with all systems functional. I doubt this jag will ever go "classic collectible" so I am about to transplant some made in the USA chevy small block horse power under the hood. Would greatly appreciate feed back from members who have done this conversion and any problems that can be avoided through proper planning.

 

I've news for you. The XJS Convertible is fast becoming a popular classic and is fetching serious money here in the UK at least. Please don't spoil the car with a cheap US "cooking" engine. Parts are available for the existing Jaguar engines, (6 or V12), although you may have to get some of them from UK suppliers.

 

Roadking,

I did an XJS 15 years back with good results. The advice about not doing a convertable is good. Heed it. You will be money and joy ahead if you have the convertable V12 overhauled or do it yourself. I don't understand why a 66K V12 needs a complete overhauling to begin with. If you have never rebuilt an engine I do not recommend that you start with a JAG V12.

Your idea to put a Chev small block in an old Jag is not necesserly a bad one, you just got the wrong car. An old XJ6 (series 1 or 2) or XJS coupe (pre 1985) is a better choice. Better yet, buy one that is an older "quality" conversion and freshen it up, There are a number of them out there-- cheep. The money you save could be applied to cosmetics ie, paint & interior.

 

Having been a corvette enthusiast and owner for years I understand the value of originality. However all corvettes are not created equal ie the c4's are not very desirable. I mention this as my 1996 xjs convertible is my first venture into jaguars so I have no idea as to the potential "classic" possibility with this model. I had responses that suggested I not modify this particular Jag with a v8 conversion as it has classic potential. I should add it is a 4.0 6 cylinder not a v 12. I would not consider modifying a car that has classic potential. If this is the case than I would leave it as is. If my sources are correct only 6000 + models of this jag were built. As mentioned in my first post it has 66k original miles and all systems function as they should. Initial problems were an excessive oil leak that the seller managed to hide. Initially it appeared to be the valve cover gasket. Replaced that with some success as the leak slowed down but I still have oil staining the garage floor. So its back under the car to see where this is coming from. Fortunately it is not front or rear seals as those areas are dry. I've had several jag owners tell me with a wink that all jags leak oil, it is part of the beast. I say crap on that. I don't believe any motor company would produce an engine for a high line car and turn it loose for production with oil leaks. Second problem that developed the day after taking delivery was the left blower motor. It would not shut off. The dealer said it was the relay, parts and labor $1200.00. Took it to a private import shop. They said it was the climate control switch, $900.00 plus labor. Quickly realized part costs for this beauty are off the chain. So I made my own fix for less than $15.00 in parts. I pulled the #3 20 amp fuse in the left fuse box, spliced in a 20 amp fusible link, ran the wires under the console to a 20 amp toggle switch I mounted in the left ash tray. I do not smoke nor do I let anyone smoke in my cars so it was a perfect hiding place for the switch. Now I just manually control the left fan, no problem. Also had to replace the front shock rubber mounts as they had deteriorated and the shocks were banging on bumps. A low cost fix and about 1 hour of my time. She is a fantastic highway car, solid, stable and quiet. Actually quieter than an 06 Mercedes convertible I had. Next I need to refinish the wheels. They are also original to the car and the clear coat is beat. A strip and reshoot will return them to near new condition. Just completed one and it looks great. Thanks to the members who replied to my post. Comments and suggestions are appreciated.

 

Leave the six in the car(less maintainence than the 12 and good for a ton of miles). your oil leak may be coming from the cam chain tensioner. another place to look for leaks are the power steering hoses and fittings.

 

The 4.0L six cylinder engines usually stay dry. 'Tis the older models that are notorious leakers. Your example proves the "usually" (as opposed to "always") in my first sentence :-)

As for the converson...it's your car and you can do what you like. As far as I'm concerned, increasing horsepower is the most legitimate reason to make the swap, so my hat's off to you as far as that goes.

If you're thinking a swap will save long-run money or add future reliability...and I'm not saying you are.... I can almost promise you it won't. The 4.0 Jaguar six is reliable and notoriously long lasting. And, since you're a Corvette guy, you know as well as anyone that having a Chevy engine under the hood doesn't guarantee the ultimate in reliabilty by any means. (I know because I spent the majority of my adult life as the service manager at a Chevy dealer.)

As for future values, yes, I think there is *potential* future value in the late XJS convertibles. I don't think it'll ever reach the level of an E-type of classic Corvette...the icon/cult aspect just isn't there....but I do think there's potential. If yours is an extra clean example you might wanna do your best to preserve it in original form and, as others mentioned, find an earlier coupe for the swap.

Cheers
DD

 

Thanks to the members who replied to my post. I have decided to not make the V8 conversion and will keep the jag original. The mechanic who replaced the valve cover gasket said the car was a "nice piece" and had not been "beat on". So if it is not broke, don't fix it. Any one who expects a 14 yo car to be perfect needs a reality check so the repairs I am doing at this time are reasonable in my mind. Most maintenace and minor repairs I can do my self. Need to add a set of metric tools to my kit as mine are all SAE. I leave the engine and trans to the pros. The oil leak definitely needs to be stopped. I can keep a pan under the car in my garage but friends and family can get annoyed when you leave oil stains in their driveways. Definitely not power steering or trans fluid, wrong color and consistency. So back to the repair shop Tuesday and see what is still leaking. Will post results when I know.

 

Good choice, Roadking. I'm not a purist by any means, but a perfectly good engine in a perfectly good Jaguar should be retained if for nothing else than being able to always say you own a Jaguar. There's a reason some Jaguar owners call those with Chevy engines "lumps".

 

INTERESTING: You know I think you have to own both types of Jags to have a credible opinion.

I have become an XJS and XJ6 enthusiast in just recent years...

My rare edition XJS (2) 89 91 collectors examples are both low mileage around 50K, and are the V12 variety.I love them both, well except for the damn seat belts in the 89... All Original

Now on the flip side I have owned (2) and currently have XJ6'S BOTH WITH V8 CHEVROLET 350 conversions. One a TPI and the other with carburetor,
TOP Quality conversions. Both very powerful, etc...

What do I prefer? I prefer non conversion. Taking a Jaguar and downgrading it to a Chevrolet V8 similar to a corvette or a camaro makes the Jaguar lose its original feel and charm.

Are the conversion cars fun to drive, sure, absolutely. Do they have good performance, durability and affordibilty with the chevrolet transplant, absolutely.

Is it still a Jaguar? No

I have become somewhat of a purist plus I have come to realize that owning an original Jaguar is not a reasonable and cost effective car to own like a Toyota in example. Meaning low upkeep and overall affordability...

So overall I would have to say that pre Ford Jaguars should stay Jaguar,,,Much more enjoyable vehicle when kept like this in my opinion. I look forward to driving my V12's each and every-time I drive them...

If I wanted a Chevrolet V8 Ill buy another Supercharged Corvette or Camaro, Ive owned both and enjoyed both. But the transplants take away from not only the donor car but the recipient as well.

Not sure what kind of remarks I might get from this post but I just wanted to put it out there..

 

Oil leaks are sometimes apparent, but often not. An old trick I used in servicing classic English motorcycles was to: first clean the motor. Then lightly spray the suspect areas of the motor with a spray-on jock itch powder. The powder will stick to a clean motor, and the oil leak will soon become apparent.

 

As I mentioned earlier, this is my first venture into the Jag world. I can repair SBC in my sleep but the 4.0 jag was a bit intimidating at first as it was "foreign territory" to my made in the USA experience. Initially I suspected the leak was around the oil filter area but I could see it was not coming from the filter seal. There was a pair of hydralic hoses that mounted into a connection below the oil filter and the leak appeared to be there. Being ignorant of the engineering of this motor I decided to let a "jag mechanic" inspect it. If there are any mechanics reading this here is why the general public ranks you with car sales men when it come to integrity. I was told they would power wash the engine to remove all external oil, add a uv dye to the oil, run the engine for an hour and black light the engine. I got a call that I had a leaking valve cover gasket, something I could have done myself but the car was in the shop so I said do the work. Charges as follows, $42.50 to check for leaks, $76.91 for the gasket, $85.00 installation, $12.00 shop supplies, $15.15 Fl sales tax, total $231.56 for that repair. Having owned an auto body shop in my younger days, I have no issue with the amount of a repair bill. I can always elect not to do the work. What does **** me off is when I get screwed. The next day I pull the Jag out of the garage and bingo, there is still oil under the engine area. Went back to the Jag shop and was told there were additional leaks around the oil filter housing, about $750.00 parts and labor. Now I get suspicious, how did they miss this to begin with? I saw that myself without the uv dye bull****. So I tell him I'll go home to "think it over". Now I just happen to have a "black light" left over from my hippie days so I dig it out, plug it in and shine it on the oil puddle. No, it does not glow!! So I know this mechanic is full of crap and I chalk it up to "lesson learned". This is probably more info than most of you care to read so here is the solution. All the experienced Jag owner/mechanics already know what the problem was. The two hoses I referred to were to the oil cooler. The housing they thread into below the oil filter has two "O" ring seals. I realized the oil had to be leaking from those seals and running down the hoses which made them look suspect. Also the oil pressure sending unit was leaking. Cleaned the hoses off and saw they were intact. Bought two seals and an oil sending unit from Jagbits. Spent about $70.00 and a few hours of my time, problem solved. Now the only thing I leave on the floor is a bit of water condensation from the ac. I am discovering for a 6 cylinder this is a very thirsty engine but I am getting more attached to this car and enjoy driving it. Finally I miss spoke the mileage. I bought it with 59k not 66k. The 66k was a 1986 12 cylinder 2 door I decided to pass on and buy the 96 convertible instead.

 

Glad you got the oil leak sorted, but please please will you put in a few double returns when you are posting..

It hurts my old eyes.

The 6 is not as thirsty as the 12.

Many thanks.

 

TL;dr

My eyes are old as well :-)

Sorry.

DD

 

Yes but your point is not valid... SBC belong in a Chevrolet. Its not just the motor. Jags are troublesome cars with their Electronics that the Brits never took the time to improve upon over the years. Only a Jag Mechanic can address those because its just damn hard to know where the hell and how it all works. I understand I.e that a Ferrari or a Rolls Royce have very costly tune ups and brakes ETC. BUt you dont see SBC going into them regularly. What I say is that certain cars need certain levels of maintenance. And the Vultures that call themselves Jag and Mercedes and Ferrari Mechanics feel that its appropriate to charge ridiculous amounts of hourly fees. Im sure they in their own minds think that they have to have special equipment and special training to work on these beasts. But I think overall its just greed. My Jag Mechanic for example gets $60 an hour... How many professions do you know that get this hourly rate of pay... Its BS and they have the market cornered. If these mechanics would be more realistic in their fees I think there would be more work for them and there would be allot more original Jags cruising the streets of small town USA...SO in closing as it stands; own a Jag; its cost money to keep it running. NO cheap fixes... Do I like it? Hell NO...Probably going to stay that way for a long time as well...

 

In my opinion a conversion to a modern LS series Chevrolet makes some sense with several conditions and limitations. Don't do it unless you are prepared to do it yourself. The reason is that the cost is just too much otherwise. Don't do it if you feel the XJS will be a classic someday.
But if this car is to be a true GT driver that you will drive for +100K miles, taking long cross country trips; you intend to keep the car for many years; and you are an accomplished amateur mechanic then the swap can be interesting, the process fun and the enjoyment unmatched.
I have done several swaps, including a SBC into a XJ6 over a Christmas weekend in the early 80s. I learned a lot along the way. I would not hesitate to install an LS motor. It is lighter than the Jag, produces more power, is more reliable, has cheaper parts, probably gets better gas mileage and is easier to service. The small block Chev, in my opinion, is old technology not worth considering. I have found that the devil is in the details though. A good swap looks OEM and behaves better.
No doubt you will not see many swaps into Rolls or Ferraris. Owners of these autos are rarely hot rodders. The cars are rarely driven beyond city limits.
Presently there is a mania amongst auto collectors for "originality", and if collecting is your bag then by all means maintain this originality.