1992 Jaguar XJR-S

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Discussion

craigjm

17,909 posts

199 months

Thursday 20th October 2016
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If the Zytek is borked I wouldn't for a second think about a second hand one! Apparently they are tough to repair too. Get yourself an Emerald ECU and have it programmed on a rolling road. That's what I am going to do eventually and have three switchable maps, one for motorway economy, one for everyday driving and one for some noise and holding gears to the red line!

darkyoung1000

2,025 posts

195 months

Thursday 20th October 2016
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Lovely, I've always had a soft spot for the XJR and having taken a plunge into X308 ownership for Le Mans last year (for only 5 months admittedly), they appeal even more.

Keep us updated!

Tom

craigjm

17,909 posts

199 months

Wednesday 26th October 2016
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Dave, what diff do you have in that car. As you know I have the same engine but I dont know whether they changed the diff. Mine is a 3.54 was wondering what it should be to match that engine

anonymous-user

Original Poster:

53 months

Wednesday 26th October 2016
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craigjm said:
Dave, what diff do you have in that car. As you know I have the same engine but I dont know whether they changed the diff. Mine is a 3.54 was wondering what it should be to match that engine
It should be a 2.88 with the 3 speed autobox, and top gear in that box is 1:1. From fag packet maths that sounds about right for my car.

I imagine a 3.54 would make it quite lively off the line but it must be screaming at higher speeds? From memory when they moved to the 4 speed box with an overdrive 4th gear they dropped the final drive ratio to liven up acceleration a bit and still drop the engine speed in top gear, and the Pre HE cars had a higher ratio too.

craigjm

17,909 posts

199 months

Wednesday 26th October 2016
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Need to look into that then. Currently the car is doing a touch under 3000rpm at 80mph

anonymous-user

Original Poster:

53 months

Wednesday 26th October 2016
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craigjm said:
Need to look into that then. Currently the car is doing a touch under 3000rpm at 80mph
So is mine, are you sure it's a 3.54? I need to re-do my maths to check.

craigjm

17,909 posts

199 months

Wednesday 26th October 2016
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dme123 said:
craigjm said:
Need to look into that then. Currently the car is doing a touch under 3000rpm at 80mph
So is mine, are you sure it's a 3.54? I need to re-do my maths to check.
Yeah, im also on 17 inch 235 tyres though

anonymous-user

Original Poster:

53 months

Saturday 29th October 2016
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Well I've had my first snag. Went to unlock it today and the central locking didn't fire. Uh-oh. Battery is dead flat. Now I can't say I'm particularly surprised, it's a crap brand battery and way too small so I think someone just chucked it in to get the car moving at some point in the past.

Internet wisdom says it's an 096 battery, but having been bitten by this before I actually measured the battery tray and it absolutely is NOT an 096. I believe it's an 027, so I'll pick one up tomorrow. Turns out that a "Lion" battery might be cheap to buy, but Lions drop dead as soon as the weather gets a bit cold.

craigjm

17,909 posts

199 months

Saturday 29th October 2016
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The correct battery definitely is an 096. The 027 is only 60amp whereas the 096 is 75amp.

anonymous-user

Original Poster:

53 months

Saturday 29th October 2016
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craigjm said:
The correct battery definitely is an 096. The 027 is only 60amp whereas the 096 is 75amp.
From what I can see on the JEC bulletin board they must have made a change sometime after '92. I took a tape measure to the battery tray and there is no way a 096 will fit. I've also measured the top bracket that sits around the battery and that is 175mm wide x 255mm long. A 096 battery is 2cm too long to fit inside the bracket or in the tray, it's 175mm x 278mm. An 027 is 175mm x 242mm.

I'd far rather have a bigger battery, believe me!

craigjm

17,909 posts

199 months

Saturday 29th October 2016
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An 027 is physically the same size though just lower ampage

anonymous-user

Original Poster:

53 months

Saturday 29th October 2016
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craigjm said:
An 027 is physically the same size though just lower ampage
From everything I can find an 096 is 278L x 175W x 190H and an 027 is 242L x 175W x 190H. 278mm is comfortably longer than the largest battery that'll fit under the bracket or in the tray.

I have read on one battery finder site than an '88 - '92 XJS uses a 075 battery, which is the same footprint as an 027 but 15cm shorter.

craigjm

17,909 posts

199 months

Saturday 29th October 2016
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The X300 V12 6/0 XJ post 1995 runs an 072

anonymous-user

Original Poster:

53 months

Sunday 30th October 2016
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Right I got to the bottom of this. Here is a diagram of the battery tray for early facelift cars. If your VIN is 1000 or so later than mine you got a clamp on the bottom of the battery rather than the top frame.



The original fit was a 088 battery which at 245mm L x 175mm H will fit exactly inside that frame. They are 220mm high and the couple of I can find to buy are 68Ah and 505 CCA. They are not a common size and there is a limited selection available now.

Other owners have used 075 and 027 as they will fit. They both have a 242mm L x 175mm W footprint and vary only in height. Both are widely available from various manufacturers. Having had several strong recommendations from owners and seeing an entry in the Jag-Lovers enormous book to running an XJS I have decided to try an Optima Red Top AGM battery that fits almost exactly in the right place. This kicks out a substantially higher starting current than any of the lead acid originals and there are owners who've had them for 7 - 8 trouble free years. They self discharge more slowly than standard batteries and are sealed and maintenance free.

The battery in there was an off brand type 063 with 40Ah of capacity and a CCA rating of 340, so a Fiesta or Corsa sized battery. I am amazed it could even turn the engine over, and not at all surprised it's died of over exertion.

craigjm

17,909 posts

199 months

Sunday 30th October 2016
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An O63 was the standard battery for any BL/Rover car under 2.0 engine size during the 80s and 90s. I am amazed that even kicked it over.

anonymous-user

Original Poster:

53 months

Sunday 30th October 2016
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craigjm said:
An O63 was the standard battery for any BL/Rover car under 2.0 engine size during the 80s and 90s. I am amazed that even kicked it over.
Well the car is always reluctant to fire when even slightly warm or hot, it turns over for 2 - 4 seconds before catching. Starts instantly when cold. I'm wondering if this feeble battery is the cause, that the voltage is sagging too low when turning over the engine. Seems a long shot, I was thinking it was more likely to be an ignition or sensor problem, but I'll find out on Tuesday.

anonymous-user

Original Poster:

53 months

Friday 4th November 2016
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Well I've now found my two first bits of bodgery. Firstly I went to change a headlamp bulb as only one is working on full beam. Turns out some monkey had lost the spring clip for the NS lamp so had stuck the bulb in with silicone sealant. What the fk goes through these peoples tiny little minds?? I'm going to get the lamp out and see what sort of mess they've made, and try to get a new spring clip.

Second bit was to find out why the Radio permanent power feed kept blowing fuses. Turns out someone had wired the switched and permanent 12V from the car into the replacement head unit the wrong way round. Easy mistake, easily rectified. Of course that would be too sensible so instead they joined the two cables together with a scotch block. As soon as your turn the car off the radio tries to keep going and draw current from the permanent 12V feed and blows the fuse. Auto electrics really does seem to be 95% bodgers. Probably explains the battery getting flattened too.

anonymous-user

Original Poster:

53 months

Sunday 6th November 2016
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Fixed the cruise control today! In 1992 they moved the XJS over to the system used in the XJ40 and later X300 so it has a vacuum pump fixed to the inner wing, a separate dump valve, and then a smaller bellows than the old system. The bellows held a vacuum so I thought I'd start with the basics and cleaned all the connectors. Success! It worked. For a bit. Well, half an hour.

Stopped working again now, and the heated seat that worked once has also decided it's had enough and the LED on the switch doesn't even come on. At least I know the cruise CAN work! I also discovered that to top it up the oil from the E mark to the F mark on the dipstick takes 2.6 litres of oil. Wow.

Edited by dme123 on Sunday 6th November 14:25

craigjm

17,909 posts

199 months

Sunday 6th November 2016
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Split bellows used to be a common cause of the cruise control failure.

The 6.0 v12 takes 10 litres of oil for a complete change!

anonymous-user

Original Poster:

53 months

Sunday 6th November 2016
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Absolutely lovely barge, good work!