They are correct about the weights in the distributor being a possible cause. Another issue with those cars was the catalysts starting to clog. I will share an old test of mine to see how well the car was performing. If you leave your car in first gear and accelerate hard the car will override the governor in the transmission and shift into second gear at about 6300 rpms. When this shift occurs the car should launch itself. If the car shifts out below 6000 rpm you have a possible ignition issue or partially plug cat. If you do this with the cats removed at times it will break the rear wheels loose on the 1-2 shift. It was always fun to show a customer how fast their car would go. I know it does not work on the face lifted cars(1992 onward).

 

Have you looked at Classic jaguars transmission conversions kits? They have several 5 and 6 speed kits. Complete. They recommend the 5 speed because of ratios. They are pricey, however.

 

Have you considered the classic jaguar transmission conversion kits. They have 5 and 6 speed conversion kits. Pricey though.

 

There is a thread on here by a guy that converted his car using a "complete" kit. Didn't turn out that way. The bellhousing is offered by at least a couple of different vendors. From there, its transmission, flywheel, of course clutch,pp, and tob. Then there is the hydraulics. If you have a ABS car, the brake pedal housing gets tricky. I have pieced mine together, and I'm thinking I will come out less expensive. Maybe 3K? But lots of time spent looking at all options.

 

3k sounds a lot better than 5. I have noticed that one of the kit vendors sells components. Your approach sounds better. I have an early 1989 coupe, so don't have abs. I have lot's of time, a shop with hoist, and a couple of other cars to drive, including the xj6 with chev 350. I do appreciate your input and would like to stay in touch.
jack

 

My car is a complete hodge podge so to speak. I am working through a lot of things. My 97 XJR actually has a mounting boss that looks like it could be drilled for a clutch master cylinder. I only say that, because the XJS was offered with a straight drive very early. (1975). I really wonder if the pedal housing on the non abs car could be modified to accept the Jaguar clutch master cylinder? It is what I am using. It is a odd looking thing that saves a LOT of space, as it is verticle. Have you checked out the Classic Jaguar parts section? A wealth of info just looking at the exploded parts diagrams. I am using a after market center force hydraulic throw out bearing. The bell housing is available. What would be really good, is if you could get hold of the guy in Texas that I sold my E-type 4 speed, bell housing, flywheel, to and see if he ever used it? I actually liked the 4 speed better than the 5 speed. I didn't drive it out on the highway much, so the 5 speed wasn't much gain. First gear was so short, that I could start off in second with no problem. I have another one of these Tremecs. One of my big costs was having it machined for the different shifter position. It is NOS, never ran. I can't imagine ever using it, would consider selling it to another nut, er, enthusiast I mean, lol.

 

Here is the clutch master on the XJS I'm doing:Clutch Master Cylinder-From (V)148945 - Parts For XJS from (V)139052 to (V)179736 | Jaguar Heritage Parts UK

 

I bought the clutch pedal for 125.00, and am going to modify my brake pedal by grinding down the pad to the size of a manual brake pedal, so I can use stock rubber pads.

 

Is the 6 that much stronger than the 5.3? Have not checked the Jag parts section.
I agree with you in that the pedals are going to be the big issue.

 

Not sure about stronger. I went looking for another 5.3 to rebuild, then drop in my 89 after it dropped a valve seat. I dumb lucked up on a early 94 6.0 and well, the rest is history. The 6.0 is just a stroked 5.3. Same bore., cams, etc. I had a 94 XJS 6.0 convertible, and it was certainly a nice running engine. However, that may have had to do with it being MUCH newer than any other XJS I had owned. The 5.3 in my 71 XKE was lots of fun with the manual transmission. Its all just want a feller wants to do, ya know?

 

It appears that when raced the 6.0 is used. You seem to have owned a number of XJ's. must be nice. Was there an issue with the 5.3 71. It was already a manual. Took my chev powered 6 out yesterday. It is a joy to drive. No V12 issues. Oh well. I think I will get to like the 12 as well. In time.
Have a great day.

 

The 5.3 was often stroked to 6.0 by companies like TWR. The odd thing to me about the V12 is the way it "feels" when running it at what some might call high rpm. It will purr at 5K. After getting the ignition changed on my 71, I literally could run it 7200-7400 rpm with no fear of it breaking. I also have a Chevrolet powered 6. TR6 that is. 302 Chevrolet with a muncie 4 speed and Corvette diff with 4.10:1 rear gear, lol. I only break it about every time I drive it, lol
I grew up in cars. My father owned a body shop, and a dealership. I changed cars often. At 55, its really hard to remember all the cars I've traded, owned, built. Not bragging, its just the way it was. The XJS is a neat GT kinda car. But the most fun car I can ever remember having would have to be a toss up between a MGB that I put a Olds 215 and T-5 in, or the 87 Buick Grand National. Always wondered what that V6 would be like in the class and style of the XJS.
To me, the XJS is just a pretty car. Very very under powered though. Maybe even one of the 4.2 Supercharged V8s? The possibilities are endless, lol

 

Well, I finally found my rev problem. It was the secondary coil located if front of the radiator. I purchased an MSD 8207 in the hopes that I could use it as my sole coil. No such luck, I lost 1000 rpm ie it started missing at 4000. So I put the original primary coil back in and went back to missing at 5000. Then mounted the MSD in front of the Radiator as the secondary coil and now have basically unlimited rpm. 7000 is easy. More power over the whole range. What a difference. I too have a 6 with chev 355 vortec heads. Real strong. Have a ZZ4 LT1 roller cam engine I am building this winter for the 6. I have removed the mufflers and resonators, went 2.5 pipes and magnaflo mufflers, more power not much change in noise. I do appreciate your help and input. I am still interested in a standard trimec 5 speed conversion.

cheers,
jack

 

I bought a quicktime bellhousing, but there is also a aluminum one offered from
V12 Jaguar Bell Housing
I blew a clutch apart in my TR6 V8, and feel that the scattershield on it most likely saved me from bodily injury. Have a cousin that lost part of his foot in such a incident. The quicktime is steel, but was about a 100.00 more than the quicktime. A look at eBayUK, might just find you a pedal housing along with the clutch master, etc.
From what I could come up with, the shifter must be located about 24" from the back face of the engine. From there, its just your mechanical imagination. I had my machinist turn down a pilot bushing I bought from NAPA for 3 bucks. I think Bill charged me 10 to turn it down to fit my crank.
The one thing that I can caution on is the Tremec. That is what I put in my XKE, and promptly destroyed the 2nd gear syncro. It cost 600 to repair!! They don't seem to like power shifting. I kinda wish now I had bit the bullet and went with the Richmond 6 speed. I learned to drive my XKE with a little more respect for the transmission, and know that going into this conversion on my XJS. So far, I have only heard that a manual trans in the XJS truly is the best modification you can do to it.
I have not purchased the TOB yet, but plan on finding something suitable as I get this 6.0 put back together. I have the triple disc clutch and flywheel from 10000RPM, but am very concerned about its streetability. It takes less than 1/4" to engage. I may wind up buying a standard clutch and pressure plate, and having the clutch relined with Kevlar fingers to avoid killing it as I did with my XKE. I put 4 clutches in it from doing rolling burnouts. The V12 loves to rev, lol.