Hey there,

Has anyone here ever heard of the XJR-S having a different crankshaft than the standard 6.0l V12? I'm not talking about the TWR 6.0l... Just the 5993 ccm V12. According to a user in Germany, his XJR-S from 1992 has a special crankshaft making exactly 5993 ccm and it comes with Cosworth pistons...

All of my litrature says nothing about Cosworth parts nor does it state that the engine is any different than that of the standard 6.0l V12s in facelifts...

I know the TWR 6.0l engines are more powerful, have a different crank, different conrods and have a different overall displacement due to these differencss and I would understand, that the TWR engine could have some totally different pistons due to it being a 'tamed' race car engine, but I find it hard to believe the standard XJR-S has something like that...!?

Anyone heard of this?

Cheers

Damien

 

Daim,

Remember that there are 3 different types of 6 litre engines (+ the Lister 6.0 engine!)

The first one was the TWR 6 litre engine. I'm not sure of its exact displacement. I have read that it used a longer throw 80mm crank, but I've also read that it had a bigger bore and specially forged pistons. I have also read publications where it was stated that it had Cosworth pistons.

Then there was the 6 litre engine that was developed by JaguarSport for the pre-facelift XJR-S. This used a long-throw 78.5 crank to give a displacement of 5993 and a compression ratio of 11.2:1. This engine continued into the facelift XJR-S. It used Zytek engine management and I've also read that it had Cosworth pistons.

Then Jaguar developed the "standard" 6 litre engine and the XJR-S ceased production. The new "standard" 6 litre engine also used a long-throw 78.5 crank, displaced 5993 but had a compression ratio of 11:1

As JaguarSport was partially derived from the original TWR team, I think it's quite possible that the XJR-S 6 litre had Cosworth pistons.

Not sure if that helps or confuses!

Paul

 

Are the special 6.0ls somehow identified via a different engine number?

 

Daim,

XJR-S & "standard" 6.0 XJS engines can both be identified from the engine number. XJR-S engines start off with 8W.... and "standard" 6.0 litre XJS engines start off with 8D...

Paul

 

Fantastic! That is something I've been searching for... So this 'one off' engine, as the man states, can be identified... Just for general interest...

 

I don't think its a one off. I was of the understanding that both my pistons (cosworth) and the crank are different. I seem to remember being told that our R-S's have a forged crank as opposed to the later cars which have a welded crank... hope that helps.

 

That may be a typo but no cars had welded cranks. The vast majority of V12's ran forged cranks although some later on had a chilled cast crank.

 

Yeah, I was reading at the time something on stroke variants which listed 'welded standard crank'.. my bad. Anyhow, the point I was trying to make is that the R-S did have a different forged crank from the standard cast iron production crank. ;-)

 

Probably just splitting hairs but l would have said the "standard" crank in a Jag V12 is the forged steel crank. Relatively few were the cast variety and as best l remember they were restricted to some of the production 6 litre models.

 

5.3L use a EN16T forged and the 6.0L used EN40 forged until Ford introduced the cast crank about the time they went EDIS.

 

Warren,

Do you know the date at which the cast crank was introduced? I had read that the XJR-S used a forged crank but the "standard" 6.0-engined model which superseded the XJR-S from April 93 used a cast crank.

Paul

 

Jaguar repair operation manual lists 6.0 L engine in model year 1993.25 on as forged steel crankshaft.
I read somewhere that later 6l used chilled cast iron crankshaft, but don't know when this happened.

 

I believe all XJS models had forged crank. The cast crank was introduced after 1994 in I think the X300.

I have a 1994 6.0L engine out of a US XJ12 (soon to be 6.7L) to go in my XJS and it has a forged crank.

 

As far as l can see the cast crank appeared alongside the nippon denso engine management in the 1995 X300.
If your motor is running lucas or marelli ignition it will have a forged steel crank.

 

Warren / Paul_59,

Thank you both for your replies. I've been doing a bit of digging around and it seems the crank changed at the intro of the x300 and at engine number 12471. That means that early standard 6.0 XJS had forged cranks (as per XJ40) and late 6.0 XJS (from about VIN 199400) have cast cranks (as per x300).

Paul

 

I'm still waiting for the engine number... He won't provide it...

 

why not use a good condition cast crank?

Ford probably knows more about chilled nodular cast iron cranks than anybody else!

i'm quite sure a good cast V12 crank could easily stand up to 500 HP!

 

Pre-facelift XJR-s was built by TWR, the facelift cars I am not sure but by this time maybe Jaguar were building these. From what I read the TWR 6.0L (road engines) used a 78.5mm crank stock Jaguar rods and cosworth pistons. cold air intakes and free flowing exhaust and made around 380hp.

 

Warren,

As I mentioned, remember that there is a difference between the TWR 6.0 engine built up until 1988, and the XJR-S 6.0 engine. The XJR-S was assembled by JaguarSport, not by TWR, although it was built in the ex-TWR building. The TWR 6.0 uses an 80.0 crank, the JaguarSport 6.0 uses a 78.5 crank.

Cheers

Paul

 

So that means the TWR engine would be 6.1L. All the literature I have read quotes it as 6.0L. I'm not sure

AJ6 list the XJR-s crank as 78.5mm, doesn't really say if this is the TWR or JaguarSport????