by cass3958 » Tue Apr 07, 2020 4:10 pm
John you are right your chassis number should start with a "P" to indicate it was a factory fitted PAS system.
To retrofit the PAS steering box to the MK2 or S Type there has to be an indent in the front subframe cross member for the box to sit in as the PAS steering box is that much bigger than the standard non PAS box. When you do the conversion to PAS it is quite easy as long as you have all the parts and one of those is to change the front subframe over to the later one with the indent. I have seen some where the original cross member has been cut and then rewelded to create the indent for the PAS box to sit in but then you have to trust the welding skills of the fitter to get it right.
I think I am right in saying the later Adwest Marles PAS did not come in until 1966/67 on the S Type when it was fitted to the Jaguar 420 and 420G.
Taken from Wiki on the Jaguar 420
A novel mechanical feature that the 420/Sovereign shared with the 420G was Marles Varamatic power steering,[4] which was offered as an option on the 420 but was standard on the Sovereign. Built by Adwest Engineering Co Ltd of Reading, England, it was a "cam and roller" system in which the non-constant pitch of the cam resulted in a variable steering ratio, with the lowest gearing being at the straight ahead, rising rapidly to either lock. The rise in gearing (equivalent to a drop in ratio from 21.6:1 to 13:1) occurred almost entirely within the first half turn of the steering wheel from the straight-ahead position. The effect was to give very light and relaxed steering at the straight ahead, with quick reaction when cornering. There was no adjustment in the behaviour of the steering in reaction to road speed. A very few of the last S-Types were similarly equipped.
John you are right your chassis number should start with a "P" to indicate it was a factory fitted PAS system.
To retrofit the PAS steering box to the MK2 or S Type there has to be an indent in the front subframe cross member for the box to sit in as the PAS steering box is that much bigger than the standard non PAS box. When you do the conversion to PAS it is quite easy as long as you have all the parts and one of those is to change the front subframe over to the later one with the indent. I have seen some where the original cross member has been cut and then rewelded to create the indent for the PAS box to sit in but then you have to trust the welding skills of the fitter to get it right.
I think I am right in saying the later Adwest Marles PAS did not come in until 1966/67 on the S Type when it was fitted to the Jaguar 420 and 420G.
Taken from Wiki on the Jaguar 420
[i][quote]A novel mechanical feature that the 420/Sovereign shared with the 420G was Marles Varamatic power steering,[4] which was offered as an option on the 420 but was standard on the Sovereign. Built by Adwest Engineering Co Ltd of Reading, England, it was a "cam and roller" system in which the non-constant pitch of the cam resulted in a variable steering ratio, with the lowest gearing being at the straight ahead, rising rapidly to either lock. The rise in gearing (equivalent to a drop in ratio from 21.6:1 to 13:1) occurred almost entirely within the first half turn of the steering wheel from the straight-ahead position. The effect was to give very light and relaxed steering at the straight ahead, with quick reaction when cornering. There was no adjustment in the behaviour of the steering in reaction to road speed. A very few of the last S-Types were similarly equipped.[/quote][/i]