Good afternoon Team,
I am about to start installation of the Ole Mobek modification to a HE V12 with CEI ignition. Part of the prerequisite for the system is that the harmonic balancer has a crank position sensor system, Ole recommends a Marelli harmonic balancer as the solution. Does anyone have a source for a second hand or repro unit? I am currently on holiday in the UK so in particular if anyone in England or Scotland knows where the old XJ-S' were sent to I would be very grateful. Cheers Chris

 

https://www.ebay.com/itm/285449547027
But the pulley for the alternator is a multi V type, not a single V belt, so the alternator has to have a new pulley to match it.
Or this to rebuild your old one;
https://jaguarpreserve.com/product/r...onic-balancer/
or this

It is not hard to fix a toothed wheel to the thing if you re-use your old non-Marelli one. I am not sure what the system would read on the Marelli damper, either.

 

Thanks Greg,
The kit comes with a 'spider' that sits over the harmonic balancer which provides the input to the crank position sensor, and as TDC is marked on the CEI unit balancer I was wondering the same as you: could I attach the spider to the original non Marelli Harmonic balancer (without disturbing the balance) and avoid scouring the planet for a rather hard to obtain, Marelli unit. It would appear that the sole reason for the Marelli change is that it has a locating pin that aligns the spider with the crankshaft orientation. I have asked Grant via e-mail if there are any wreckers in SA that might possibly have one, as well as his thoughts on the modification. I'm sure he will see your post and comment providing me with his opinion.
If Ole Mobek is online he may also comment on this thread.
Many thanks for the links provided, much appreciated. I didn't know Camp Chaos sold parts.
Chris

 

Chris,

If you're in the UK at present, you could try ringing Andy Harvey:

Just Jaguar XJS Parts and Spares, all models 1975 to 1996

Cheers

Paul

 

Thank you very much Paul, I shall give him a call. Much appreciated.
Cheers Chris

 

Chris,

Email answered earlier.

That Marelli timing "thing" is a separate part, and bolted to the rear face of the balance. I included a Parts schematics to help.

Not found one here yet.

 

Thanks Greg, In talking with Simply Performance (Jaguar specialists) the Marelli Bosch alternator unit can be provided but it doesn't fit the Lucas CEI alternator bracket! So now I'm trying to establish if the Bosch bracket fits onto the orifice for the Lucas alternator......More discussions with them when I get home and can photograph my set up. Apparently my 1988 V12 HE XJ-S is right on the cusp of the Marelli system upgrade, and here in the UK that year model came with the multi groove belt? Good ole' Jag!

 

I think the only difference is that the later alternator has a 10mm diameter pivot bolt, and all you have to do is drill out the holes in the bracket and find a long 10mm bolt.

 

I was able to purchase a new/rebuilt Marelli Harmonic balancer from SPEEDYPARTSDIRECT here in the US. My original had a few hairline cracks and I could have continued using it but since I was refurbishing the engine I decided why not? Cost of the HB was $98.00 US with free shipping. If you want my old HB you can have it for the shipping cost to your country.

 

My alternator upgrade from MANY years ago.

Some spelling and "bad" words sorted before posting it here.

YES, the 10mm long bolt is all that is needed, plus time and patience.

I run twin Efans, so much more room than the standard set up.

The 11A0850 original belt is also reused.

 

Thanks Sanchez, I was just watching the video sent from Camp Chaos Chronicles, and it would appear that you may have caught your Harmonic Balancer/Damper just in time. Bob articulates how when the Damper starts to go, quick replacement will same your engine! Notwithstanding, very many thanks for the offer. Cheers Chris

 

G'day Grant,
Many thanks for this information on the V12 Alternator upgrade. Sorry about the delay, just got back from sunny UK, where I drank far too much whisky whilst swanning around the highlands of Scotland: highly recommended by the way, lovely friendly people the Scots, or so I experienced.
Couple of observations from this gem that I would like to clarify with you "on air' so everyone gets the benefit vis a vis my Marelli harmonic balancer change:
a. a Bosch XJ40 alternator (Australian delivery with multi v pulley) fits onto a XJ-S V12 engine with a bit of drilling;
b. I have established my '88 XJ-S V 12 has a Bosch 8025 alternator, and my car is an Australian delivery, so I'm thinking that bit is done, except I have the single V pulley on the front of it;
c. I have bought a new harmonic balancer/damper on Amazon ex-Taiwan using links provided by members in this thread (I think, there was some stock issues delivery to be advised?) which comes with the multi v pulley. Notwithstanding other sources of said balancer/damper greatly appreciated, as they are hard to get;
d. Thus, if I could find an XJ-40 alternator, or the Bosch multi v pulley on line I'm home and hosed.
I have a Jaguar number for the pulley: EAC 9319, nil stock global!
Do you happen to recall the Bosch number for the multi v pulley on the XJ-S?

I am going to the SNG website to see if I can find a Jaguar number for the XJ40 version, or search for one around the traps, any assistance greatly appreciated. Also begs the question, what harmonic balancer was on the XJ40 V12 cars? Also, worth a look on the parts catalogue.

Thank you again Grant for your really helpful advice and profound experience.
Cheers, Chris

 

Chris,

Just a suggestion: any part number you need, start with the Jaguar parts website, not one of the independent websites. At least you'll know the number is correct then.

Cheers

Paul

 

Good morning, Paul,
Good advice. I have found a number and availability of the pulley for the XJ40/XJ-S Facelift (JLM 11149), the harmonic balancer/damper is unfortunately not available at SNG but the number is NHF 1411AA. I will cross reference these with the Jaguar parts website, which strangely I have never used, could be an eye opener.
Many thanks, Chris

 

Yes, from a quick perusal of the website, those seem to be the right numbers.

Paul

 

It would appear that the XJ40 alternator pulley Part number JLM 1149 is compatible with the XJ-S Facelift and has a recommendation for cars as early as 1988. Further evidence is that the alternator pulley belt EAC 9369 fits earlier cars as well as the XJ40. So, that would suggest that the pulley will fit my alternator? Anybody have any evidence of this compatibility?

 

Chris,

If you check the parts website, you'll se that it's not just that JLM11149 is compatible with late XJS facelift, it IS the part number for the late XJS fitment.

Compatibility with earlier cars may or may not be an issue, but those ARE the late XJS part numbers. Just spend a few minutes perusing the Jaguar website in the XJS sections.

Paul

 

Good morning Team,
Just a quick update on the Marelli/Ole Mobek upgrade:
a. Got the Marelli damper on Evil Bay from Taiwan, I'll see what it's like.
b. Got the alternator pulley and multi groove alternator belt from SNG: fits my old Lucas alternator shaft from the Daimler so should fit the Bosch unit on my XJ-S.
Whilst I was at it, I got myself a decent damper puller/installer. Just for our member's advice I rate this Toledo tool (I like Toledo stuff), the damper came off with small pop, job done. I had a practice on an old Series 2 V12 engine I have in the workshop before tackling the XJ-S, having an engine available on a stand has helped me out several times with 'seeing' what I couldn't whilst the engine was in the engine bay.
Got a Mathewson's mug whilst visiting Yorkshire!