Ever since she came out of storage a couple of weeks ago, shifting from P to R resulted in a very slow engagement of R gear. Well, tonight we had our first really cold night since taking the car from storage, and I cranked the car and shifted into R and again it took about 10 seconds for it to start backing out of the garage. Once I stopped, I shifted into D, but I hadn't backed out far enough to be able to clear my wife's SUV sitting in the driveway, so I shifted back into R, and ... dead.

No matter how much gas I gave it, it never budged. Sat there like it was in neutral the whole time. I finally had no choice but to park it, move the SUV instead, and then roll the XJS into the grass and leave it.

Thus, my manual conversion project now gets under way. Previously, I had looked at kits from DrivenMan, but had seen cautionary tales here about that kit. So I ran a Google search just now and kits from Simply Performance and Vintage Jag Works popped up. Obviously if I had to order from Simply Performance, I'll be waiting awhile on shipment, as they are U.K.-based. Has anyone had any experience with either of these vendors? Or maybe there's another one I'm unaware of? Or has DrivenMan got the kinks worked out?

I'm not trying to do anything crazy, just go from the factory GM400 to a 5- or 6-speed, and I guess I'm going to have to keep the factory rear-end gear for the time being.

Jess

 

I use Simply Performance. Great people. Quick, helpful, good prices. Ben is the bloke to get in touch with. He'll answer latest the next morning or his staff with.

I needed loads of parts for my X308 XJ from them and they sent it all on a pallet. 2 days later it was in my yard. That is from UK to DE.

 

Great idea to convert over to a manual transmission. On your GM TH400 unit, it sounds like low fluid level, clogged filter, low control circuit pressure. These units are legendary for torque and their clutch packs are super reliable.

Please keep us posted on the conversion progress. I have always dreamed about finding a late 80's XJS to attempt this conversion. That will be a blast to drive when finished, I am sure.

 

I used Simply Performance but not for anything major.
If I use them again it will be because I have no other options.

 

Can't speak to the filter or the circuit pressure, but the fluid is at optimal level right now and a healthy pink. That was my first thought as well.

Jess

 

See, this is the issue I run into here a lot: Widely conflicting opinions about the same vendor from multiple users. Especially with the transmission conversion, there seems to be no one truly happy with the vendor experience. What happened with your experience?

Jess

 

I bought a used radiator off them, supposedly in good, leak free condition.
It took weeks to arrive and it was in a right mess. Took it to a specialist to test it and it was completely shot so had to fork out another £270 to get it re-cored.
They completely failed to answer any emails or phone calls.
The other stuff they sold me went straight down the tip as it was junk.
If I wasn't such a lazy sod I would have pursued it but sometimes you just give up.

 

I have dealt with them on more than one occasion and can only pass on my experience. Jon Thompson is bens father. I had problems when dealing with Jon during the purchase of an exhaust part. As has been stated lots of hassle no action. Eventually the wrong part arrived and after another call a full refund was given immediately. I believe around this time the business was growing very quickly and this was causing problems. I used them again somewhat reluctantly by which time Ben had taken over the parts section. He was very helpful on more than one occasion and I had no real issues. Only thing I will say is they know how to charge . Overall I would say ok for parts but I have no knowledge of the conversion or performance side of things.

 

There are guys on here who have very successfully done their own manual conversions from parts and suppliers bought in the USA. My impression and belief is that a kit bought in the UK will not be a good strategy for you to follow. There is also a view in the UK from some converters that the gearbox from the 6 cylinder car will do the job in a V12, which I believe is quite mistaken.
I also believe that documenting very precisely which parts you used, for absolutely every tiny piece of the conversion is essential to keep some value in the car. So things like clutch plates, release bearings, slave and master cylinders etc etc are clearly identified and recorded, so any parts required in the future are clearly known. In a way, an OEM style parts list and workshop manual.

 

Greg,

I tend to agree, which (I guess) puts me working with DrivenMan and/or Vintage Jag Works. I will have to do my research on the latter, as I don't recall seeing their names here very often.

The shop that will be doing the work for me doesn't typically work on Jaguars unless it's one of mine. However, they are trustworthy and competent. The owner does a lot of custom work on hot rods, rat rods, etc. He has done several custom vintage cars and I like his work. They are a bit apprehensive about doing my car but are willing to take on the challenge. I know they would feel a lot better about things if I could just drop a kit off at the door, but the more I read, the less it sounds like that's a possibility.

The one thing that's going to be an issue is custom machine work. I've seen info out there that the prop shaft has to be shaved, for instance. We'll have to farm that work out to another shop. And while I'm not really budget-limited per se, that changes if I start having to go through multiple parts. I don't want to have to buy the kit twice if you know what I mean.

Jess

 

I've got a converted V12 manual with the AJ6 Engineering tuning bits and a 3.54 diff, which is using the Getrag gearbox from a 3.6 manual, I think. I've not had problems, as yet, with the gearbox holding-up to the power and torque, but on balance, I think a more modern 4/5 speed automatic gearbox conversion would suit the car better.

 

The key component is the bell housing to connect the gearbox/clutch to the V12. This thread discusses it
https://www.jaguarforums.com/forum/x...nsight-174129/
and google produces this UK firm, and loads of others, who might be worth contacting. If the bellhousing is precisely accurate for the V12, and is correct for the gearbox you choose, the rest of the conversion is relatively straightforward. If the bellhousing is even a few thou off, it is a substantial problem to correct it.
Jag T5 ? 5 Speed Conversion for Classic Jaguars & Austin Healey - Elite Racing Transmissions


Greg

 

I went with the DM kit about 7 years ago, Everything new! TKO600, Alum FW, Zoom clutch etc. Problems were few. Shorten the driveshaft $50, ECU reworked, sent to Bywater,. I suggest taking the seats and consul out. I spent a lot of time under the dash.
I also drilled a 1 1/2" inspection hole in the bottom of the bellhousing. Reason, to see the throwout bearing work before everything is put back together.
American Powertrain sells a very interesting shifter for the Tremec 600 I'm considering, check it out

 

Follow-up: If I've got to keep the factory rear end for now, what's the current take on which transmission to get? I also see references to people custom selecting the gear ratios in the box...is that common? Or an expensive upgrade?

Jess

 

May I ask how long ago that was? I know that the son, Ben, took over from his dad. Maybe you got stuff as hisndad was still active?

 

Yeah, it was his dad, I've never met Ben.
I was very disappointed in the treatment, especially after I practically gave him my knackered Lister years previously.
Hopefully it bit him in the ****.

 

I've only dealt with Ben and he has been a real help.

 

Ok cool, maybe I'll give them another go if I need something.

 

On your question about gear ratio's trans & diff , there are probably a hundred different threads about this in this Forum. I recommend reading everyone's take on this before making a decision. IMO Its all about "what the car will be used for", highway, city driving, some track, stump pulling, etc. That's first, then comes transmission ratio choices. Then your diff gear decision. Getting someone in the USA that IS qualified & will set up a Jag diff was a real hassle for me. "Jaguar diff's must be brain surgery" in some shops. Others don't do ANYTHING JAGUAR . In any case you better have a big budget, all new parts & labor

 

BTW... I do diff's and manual conversions.