View Full Version : TR6 Jag. upper balljoint on a TR6

04-20-2007, 10:13 AM

I saw a post somewhere describing how to fit JAG. XJ6 upper balljoint on a TR6, but cold not remember where. The result looks great, but unfortunately I lost the site address. Can someone help me...



04-20-2007, 12:56 PM
Hi. J.G.C, Yes, there was an old article in Grassroots Motorsports written by J.K. Jackson (tr6 racer mechanic in Florida) he said to use the xj6 joints with two shims (xj6 takes two shims)in the front of the mounting point, this will give you more caster. There was only one problem--it doesnt work!!. I tried it and the problem was the xj6 tappered ball joint stem is larger than the TR6 stem and will not seat completly down in the hole. After more research on this subject the extra caster is not needed on the tr6, it has plenty already, but you can use the camber adjustment points to adjust the caster, if I remember right it is (approx.) for every shim added to the rear point or taken away from the front point will increase your caster 1/4 degree.---I still have 2 XJ6 ball joints for sale and cheap (free).------------------------------------------------------Got my rear and front shims mixed up on the original post--they are correct now.

04-20-2007, 10:04 PM
That's funny, maybe you got the wrong parts. Cuz' I saw the same article, ordered the joints put them on my car(and this was what 5 or 6 years ago or more. Shimmed them back measured the caster, improved by 3/4 percent if I remember right, but it's been so long. Really only big deal on doing more caster is straight line tractability.

04-20-2007, 10:37 PM
Confirmed I had the right parts. They will go on but they dont completly seat and will raise the upper wishbone up (ball joint end) about 1/2", I almost didnt notice it at first, yours might be the same way. This problem with the conversion was brought out by someone else in a prior post, it was in answer to a question I had about this 10 months ago. There was also another problem----by offsetting the balljoint with shims it puts the trunion/spindle link in a slight bind because it was designed to be in alignment between the middle of the top wishbones, with it off center it causes a bind. If your suspension was worn it might not have been too noticeable. With new suspension the steering would be harder than normal (very hard in my case) and there will be premature wear of the trunion. Also with the top outer wishbone lifted 1/2" the geometry on the front end will be changed. Several others have spoken out against this conversion in the past.------although J.K. Jackson was very clear about the XJ6 ball joints it has been mentioned in other post that it may be a different model Jag ball joint that works, but I think it still would put the trunion in a bind.

04-21-2007, 01:03 AM
You mentioned something that lit a lightbulb in my memory. If I remember properly the balljoints were NOT XJ6 they were XK 140. Big difference.

04-21-2007, 01:30 AM
I still have the article--he said xj6 but maybe it was an error. The other past mentioned ball joint was a Jag MK IV. I think if I need more caster I can get it with the camber shims. Why did you change, what differeces in feel and handling did you notice, do you race or autocross?

04-21-2007, 01:31 AM
I have the jag ball joints in my 63 and they seat. I originally tried them as described by Jackson but since the lower A arms are not adjustable in a TR4 as in a 4A or 6, I was concerned about binding and after trying it for a while, shimmed them to stock. The change in castor was quite noticeable in handling, much better for autocross. I assume there was enough "slop" in the lower A arms to allow the increase in castor. I became concerned about wear in the lower suspension so I shimmed both sides of the upper joint to "neutral". In a 4A or 6 used in autocross the jag uppers may be worthwhile, guess it depends on what you want to do with the car. Bottom line; if you are not going to race it leave it alone and keep it stock, it will cruise just fine, turn your attention to other areas.

04-21-2007, 06:04 PM
I've got the rack mounts, poly bushings, spax front shocks, lowered higher pressure springs, kyb kit shocks on the rear, 205/65R15's on the front, 205/70R15's on the rear, two Weber 40DEOE's and one SK(one WEber float cover broke and I had the SK's, just haven't gotten around to replacing the Weber cover, high volume water pump, electic puller radiator fan, Allsion/Crane and MSD ignition. I just like to drive quickly sometimes.(I usually ride my 91 Yamaha FJ1200 with 116K miles on it).Oh and the XK-140 balljoints, increased camber 1/2 degree negatively. 1/2 degree more caster on the drivers side than on the passenger side.

Main purpose of caster is returning to a straight line and tracking capabilites. As far as TR6's have enough. Well MB has 6+ degrees on a lot of years, so.........?

05-03-2007, 10:33 AM
A Jaguar shop that I know ordered a pair of upper ball joints for the TR6 to fit onto the Jaguar because they were cheaper. To make them fit the upper wishbones had to be drilled out because the centre to centre distance is not large enough. The upper wishbones are now hacked up and the shop never fixed the problem. Also the joint is not strong
enough to take the added weight of the Jaguar car.
Lots of Jag's.