www.jec.org.uk

anyone hear of them or have any of their products fitted ?

i will divulge why i want to know later......lol


BB

Hi BB

Yes I have purchased parts for my Mk2 from them.

Front and rear HB anti-roll bars fitted on pre-facelift. Would recommend...

cool

reason being

i picked up a brand new old stock steering rack , but the numbers didnt match any Jag numbers , but began with POW-A-RAK HBE 122.... so i took a punt.....

a quick google search and i turned up Harvey Bailey , but not a lot more

so it seems i have a ' tuned ' steering rack for an XJ6/XJS , but how its modified is not known ,

i have emailed them for any info they might have on it ,

anyone else know any different ?

cheerrz

BB

Hi BB,
I haven't a clue what a tuned steering rack is but I will make a suggestion which may help!
The rack tower houses a pinion shaft, on one end is the pinion (would you believe) which engages with the rack.The lower steering column fits on to the other end (at the top of the tower)
I've just nipped down to the workshop to get a shaft that just happened to be there, just to remind meself.
The shaft comprises of two halves and join together in about the centre of its length. Thinks, how do I explain the joint? The lower half of the shaft as a square section slot cut across it with a corresponding peg machined into the upper half of the shaft.These two halves engage together but a slack fit allowing about 2mm of rotary movement between them. OK so far? Now, running through the centre of both halves of the pinion shaft is a 5mm torsion bar secured at the ends to its respective half of the pinion shaft. So initial steering wheel movement twists the torsion bar until the slack is taken up in the sloppy joint.

Just to digress for a moment. Oil pressure either side of the piston in the rack is equal or in balance. When a steering wheel movement is made oil is bled off from one side of the piston allowing the higher pressure on the other side to move the rack in the selected direction.

Cor Bennett why did I start this - I hope you appreciate this BB

So if above makes sense so far- by adjusting the strength of the torsion bar and / or the clearance of the sloppy joint in the two halves of the pinion shaft will effect the sensitivity of the steering. Perhaps I should go on a little more and explain that whilst twisting the torsion bar ports in the flow control devise bleeds off pressure at an increasing rate to maximum rate when all the slack in the sloppy joint is taken up

To summarise. The only changes to the rack that I can think of would be in strength of the torsion bar or clearances to the sloppy joint

All guess work but hope it helps a little

Oldtimer

I would imagine it is basically a 'quick - rack'. They alter the turning ratio lock to lock changing the pressure valves.

Jaguarsport used a different strength torsion bar on the rack for the XJR-S (.250" ?) which reduces the assist, which I think was developed from / is the same as the steering modification that TWR offered as a stand alone pre Jaguarsport. There may also be accompanying changes in the pressure valves.

I think there was also a seperate Sport version available as part of the sports pack (.235" ?). I think the standard torsion bar is something around 1.90" to .210" and changed over the years.

There was a website somewhere with pictures and an explanation about different racks that Jaguar used that I came across when I was looking for info on what TWR changed from the standard for their "TWR power assisted steering valve and pinion assembly" option. Above is taken from a few jottings I made based on that info.

May be something to do with one you have. I think there were also a number of variations throughout the years and different suppliers were used at different times.

I have some pictures of a TWR rack somewhere, I will see if they have any numbers visible on them.

thanks for the detailed replies lads ,

i appreciate how the rack works, and was wondering on the differences to standard ,

the good news is that Harvey bailey have been back in touch with me , and told me that although the actual part number is not current or recognised, the prefix's were all associated with steering and suspension up front, and could be a ' one off ' customer request .

also

that the manufacturers supply both Aston Martin and Bently at the moment

will keep researching what i have

BB