XJS 4 pot calipers on Series 2?

288gto · Post by **288gto** » Sat Jul 12, 2014 12:31 pm

Just a quick question, can you fit XJS 4 pot front calipers to a Series 2 upright? I'm assuming that if it was that simple everyone would be doing it and posting about it. (Search revealed nothing)

Thanks,

Simon

Dave K · Post by **Dave K** » Sat Jul 12, 2014 2:08 pm

If the hole centres are the same and I think they are for the callipers then yes.
I have XJS uprights with Coopercraft XJS 4 pot callipers on my car.
Standard XJS callipers are bloody heavy bits of kit, the Coopercraft callipers are aluminium (billet of course:D )
You will need xjs vented discs as well.

Dave

288gto · Post by **288gto** » Sat Jul 12, 2014 2:17 pm

Cheers Dave, it's just that a chap near me is breaking an XJS and it all started with me looking for a 3.07 diff.
You say that you have XJS uprights on yours, is there an advantage to this? Do you have any info on what years etc are compatible?

Simon

Dave K · Post by **Dave K** » Sat Jul 12, 2014 3:42 pm

288gto wrote:Cheers Dave, it's just that a chap near me is breaking an XJS and it all started with me looking for a 3.07 diff.
You say that you have XJS uprights on yours, is there an advantage to this? Do you have any info on what years etc are compatible?

Simon

If you look on Derek Watson's website http://www.derek-watson.co.uk/brakes.php it tells you all about the upgrade. It is supposed to transform the braking and handling of the E-Type, however I haven't noticed much difference. You need the steering arms which as far as I know only he supplies. I'm not sure but I think E-Type fabs also offer the same upgrade.
I tried to do it the cheap way by getting a set of uprights and stub shafts from a local Jag breakers and supply my own callipers, turned out to be twice as expensive in the end and 3 times more hassle

Dave

Post by **Heuer** » Sat Jul 12, 2014 3:46 pm

Have you considered the Volvo brake caliper conversion? Details are here somewhere or on Jag Lovers. Other option is Zeus.

christopher storey · Post by **christopher storey** » Sat Jul 12, 2014 3:53 pm

Unlike the Dunlops on the S1 , the Girlings on the S2 are well up to modern standards, and IMHO there is really no advantage in changing them for road use

288gto · Post by **288gto** » Sat Jul 12, 2014 4:19 pm

Thanks chaps, and as Dave suggests, it may just end up a whole lot of hassle. I'm sat at home recuperating from an operation with way too much time on my hands.
I did look at Uryk's while I was up there collecting frames, but while superbly engineered, they were a bit too modern looking for my taste.
Realistically, I think it will be the Zeus or Coopercraft ones.

Simon

PeterCrespin · Post by **PeterCrespin** » Sat Jul 12, 2014 9:07 pm

I am unsure what you are looking for by fitting different brakes.

As Chris said, the S2 calipers are excellent, so the only rationale I can think of for changing would be to save unsprung mass if you change to an alloy caliper (some of which have their own downsides) or to save money if your aftermarket calipers are a lot cheaper than refurbed OEM parts (which I doubt).

I certainly don't think your braking will improve unless you increase the tyre spec and doing that would benefit existing calipers as well.

Pete

288gto · Post by **288gto** » Sat Jul 12, 2014 10:28 pm

PeterCrespin wrote:I am unsure what you are looking for by fitting different brakes.
Pete

It's just that I hate doing things twice and want to get the brakes spot on from the very outset. Given that everything has to be replaced or refurbed it seemed to make sense to do any upgrades at this stage.

Having searched various posts, forum comments and feedback like,

"....brake kit does improve stopping distances" ,
"a huge difference already....wish I had had them in the Alps",
and "Brake upgrades such as modern 4 pot calipers work well......"

made me think the extra cost would be worthwhile.

As I said, unfortunately sore and housebound at the moment and a little frustrated I can't do any manual work on the E type shell so thought I would occupy myself with some research. On a positive note I think I've found a supplier for black original style 3/8" body hole plugs as opposed to the clear ones everyone seems to stock.

Simon

PeterCrespin · Post by **PeterCrespin** » Sun Jul 13, 2014 1:29 am

I think I recognise one of the quotes as David's but be sure you're comparing apples and apples. I would agree that the S2 calipers might be an improvement on an S1 in some respects, which is why Jag switched the cars were on radials by then as oppsed to crossplies when Dunlops were first specced.

I'm not trying to dismiss your ideas but you're starting from a good base with a 4.2 and especially an S2 so I'd be running the car standard until/unless you perceive a specific defficiency you want to rectify. My bet is you won't really find much wrong if everything is in good shape.

Pete

christopher storey · Post by **christopher storey** » Sun Jul 13, 2014 7:07 am

Peter makes the same point that I made : the S2 is a world away from the S1 in braking power. The Girling front calipers are 3 pot type and not fundamentally different from those on the XJ6 . If your car was an S1, then you could be sure that there was an "upgrade" element if you fitted eg Coopercraft , but there is no upgrade in substituting aftermarket calipers for the Girlings .

Post by **Heuer** » Sun Jul 13, 2014 7:36 am

Not sure those comments were made by me and they are most certainly out of context. My car has had Zeus callipers since I bought it along with AP ventilated and cross drilled front discs. The one modification I have made is to replace the Mintex pads with Greenstuff. Only other problem I have had was caused by overheating of the servo due to a missing heat shield. I still have a bit of sponginess on first application but a second press clears it. On our return I intend to replace the front hoses with Goodrich braidedbto see if that resolves it (system has been bled quite a few times to try and fix it). On an S1 Zeus are the way to go as just about everyone thinks they are standard Dunlop. On an S2 consider ventilated discs if you intend to tackle Alpine passes but for road use the standard setup is fine. I have S2 callipers on my FHC and am reluctant to fit the Dunlpo ones back as braking is so good.

PeterCrespin · Post by **PeterCrespin** » Sun Jul 13, 2014 10:58 am

Are you talking about S2 at the rear David or do you have S2 uprighs to match the 3.5" hole centres?

Post by **Heuer** » Sun Jul 13, 2014 1:15 pm

S2 uprights. I have had the Dunlop callipers restored and have access to a set of S1 uprights but the car stops so well I am loath to revert to original.

288gto · Post by **288gto** » Sun Jul 13, 2014 1:59 pm

David, the quote is from another member with a late S1, the first is from a member with a 69 S2 and the third is from my bedside "bible" a veritable fountain of useful information entitled "Essential Buyers Guide" by an author of some considerable repute. I did however mischievously and in the best tabloid fashion neglect to quote the rest of the sentence "especially on early 3.8 cars".

Given that I intend to use the car as much as possible, I want to get the brakes up to modern standards. I can't think of any modern 250 bhp cars that don't have at least vented discs on the front. Having said that, I also take on board Peter's comment that they are only as good as the tyres.

All interesting stuff and thanks again for all your replies and info.

Simon

Post by **Heuer** » Sun Jul 13, 2014 4:43 pm

Simon

Modern cars weigh a lot more than the E-Type - even a new MINI is 25% heavier - so big tyres and huge brakes are not necessary. Suggest you try the car with the standard setup and then bolt on what you want. Biggest improvement you can make to the car is the Mangoletsi cable throttle system - absolutely incredible control and a joy to use. Next would be the Edis/Megajolt and although Ray is no longer selling the kit you can buy the various parts from trigger-wheels.com although you will have to have the bracketry and harness made up, unless we can convince John (kingzetts) to go into production. I think it was Nuvolari who said "brakes are for people who want to stop"!

Dave K · Post by **Dave K** » Sun Jul 13, 2014 5:05 pm

Heuer wrote:Simon

Modern cars weigh a lot more than the E-Type - even a new MINI is 25% heavier - so big tyres and huge brakes are not necessary. Suggest you try the car with the standard setup and then bolt on what you want. Biggest improvement you can make to the car is the Mangoletsi cable throttle system - absolutely incredible control and a joy to use. Next would be the Edis/Megajolt and although Ray is no longer selling the kit you can buy the various parts from trigger-wheels.com although you will have to have the bracketry and harness made up, unless we can convince John (kingzetts) to go into production. I think it was Nuvolari who said "brakes are for people who want to stop"!

There is a company called Nordiz that a friend of mine is working with to produce a very similar set up to the MJ. He should have more info soon.

Dave

288gto · Post by **288gto** » Sun Jul 13, 2014 10:54 pm

David

Heuer wrote:Simon

Modern cars weigh a lot more than the E-Type - even a new MINI is 25% heavier - so big tyres and huge brakes are not necessary.

Just a few curb weights for an interesting comparison,

S2 E Type OTS .............. 1321 kg
3.0 BMW Z4................... 1365 kg
Current Boxster............. 1310 kg
V6 F type....................... 1597 kg

Again thanks for all the input chaps, especially the update on the Edis/Megajolt

Simon

Link:
BBcode:
HTML:
	Hide post links

Link:
BBcode:
HTML:
	Hide post links

Link:
BBcode:
HTML:
	Hide post links

Link:
BBcode:
HTML:
	Hide post links

Link:
BBcode:
HTML:
	Hide post links

The 'E' Type Forum

XJS 4 pot calipers on Series 2?

#1 XJS 4 pot calipers on Series 2?

#2

#3

#4

#5

#6

#7

#8

#9

#10

#11

#12

#13

#14

#15

#16

#17

#18