The 'E' Type Forum

I want to put a taller diff into my 1969 US 4.2 OTS. I am not that bothered about speed off the line, but like low revving engines at motorway speeds.
What Jag models have compatible differentials with the Series II? I think 2.88 ratio would suit me best.

Steve

XJ6 are most numerous in scrapyards etc but not many have 2.88 . Or you may be able to find someone who has taken the diff out of an auto 2+2 - this is probably 2.88 if you are in Europe but may be a numerically higher ratio in the US - also I think that many XJS were 2.88 but would not be categorical about it

Are they all completely interchangeable, in respect of external dimensions? The XJS's seem to be LSD generally. Is it normal to swap the whole lump or to replace the crownwheel and pinion.

Steve

Normal to swap the complete diff casing and internals. Interestingly, I believe I saw a 2.88 for sale in Surrey in today's JEC magazine which is also available on line ( although it was described as a Z88 but I think this was a misprint - ? 275

here is the link

http://www.jaguarclassifieds.org.uk/?page=cars&id=1372

christopher storey wrote:Normal to swap the complete diff casing and internals. Interestingly, I believe I saw a 2.88 for sale in Surrey in today's JEC magazine which is also available on line ( although it was described as a Z88 but I think this was a misprint - ? 275

here is the link

http://www.jaguarclassifieds.org.uk/?page=cars&id=1372

Thanks Chris - think I speed read that and fleetingly wondered what a Z88 was. Anyway it had gone when I phoned him.
There seem to few a few 2.88 diffs about which look externally similar to an E-Type, but are all Powerlok LSD's. Some say 'suitable for inboard discs' - implying that some types might not be! Are there any gotchas that anyone knows of with incompatibility?

Powrlok is quite normal and was standard fit on Es up to about 1968 . The only IRS Jaguar diffs I can think of that didn't use inboards were ( I think ) the facelift XJS of about 1991 onwards

All Jag Salisbury 4HA-style diffs from more or less post-war to 1986 XJ and 1996 XJS have similar 'pumpkins' if IRS and innards even if solid axle. The innards don't necessarily swap perfectly, depending on ratio. The 2.88 carrier, for example,is different from the 3.54, whether PowrLok or open diff. Some S2 E-types had an open diff around 70-ish I think, although my 68, 69 and 2 70s have all had LSD. All V12s (E-type or other model) have LSD regardless of year, right up to 1997MY.

In 1986 on the XJ40 and subsequent, Jag changed to a different IRS design but the XJ-S (called XJS from about 91-on) used the same basic IRS as classic Jags right to the end, albeit eventually with outboard discs.

There was a period in the mid/late 80s when some cars used a Dana diff with no significant interchangeable parts. These are easily spotted by the absence of a drain plug and can be fitted if you use the accompanying calipers, but in all cases the lower fulcrum brackets for an E-type must be used to put the suspension/diff nose at the right angle.

Pete

Thanks Pete

I found a 2.88 Powerlok at ?300 at Black Country Jaguar

I will soon find out if it is cromulent for a S2 OTS.


Steve

'Cromulent' - love it! Not often I have to look a word up but that's worthy of Leonard Sachs and 'The Good Old Days' - or should that be Robert Robinson and 'Call My Bluff'?

Well the etymology is admittedly obscure, and historically the word has seldom been found outside a narrow Sociology context.

Oddly I remember the first time I heard it so used, the dialogue went "I don't think I ever heard the word embiggen before I came to Springfield", response: "Well it's a perfectly cromulent word".

Since then it has appeared in many reputable scientific papers, including my own (as yet unpublished) 'Degrees of Cromulence - Some Observations Toward a Classification'.

Steve

Corpulence is more my thing...

Alan Slawson [ajseng @ hotmail.co.uk] is a specialist in UK for diffs. He can offer 2,88 "renewed" for a reasonable price. I friend of me bought one and was very satisfied with the quality.
Regards Wolfgang Gatza

Thanks for the suggestion Wolfgang, but I found one at Potteries Jaguar, don't know yet how good it is. Was ?300 incl delivery locally.

A used more than 20 years old diff oftens is good to use in the church as a "gospel-singer". I would not mount an "unchecked" diff.
Regards Wolfgang Gatza