Should these be replaced? I think they are low mileage. 5k or so. Im not sure how to detect wear on these.

 

I don't see anything wrong with 'em. Throw 'em back on the car IMHO

Cheers
DD

 

yup

nothing wrong with them...


BB

 

Agreed. Plenty of miles left in those parts.

Mark

 

My experience with the AJ6 is the cap and rotor tend to binary failures, and I've been stranded that way before.

So put 'em back on, then go ahead and keep replacements handy as insurance.

**whoops: I see you're running a v12 (faked out by the 6 cylinder cap, hahaha), but the same principle applies.

 

Do the Marelli Fix Modification to the distributor, fill the rotor mount hole with silicone and you look good to go.

 

YOU DO NOT need to modify the Marelli system. Porsche and Ferrari all used the same system, in fact the dual plug Porsche Dissy cap look almost identical to the V12 Jag, and none of these guys had fires.

All that is needed is to maintain the ignition system. What causes the fires in the Cats is bad spark plugs, usually in the front 4 cylinders.

That is not a genuine Marelli cap but appears to be in good condition

 

No you don't NEED to modify it. However, what is the downside of doing it?

 

Do the porsche and ferrari systems have the same distributor shaft? maybe its shorter and doesnt arc? or maybe those cars just have easy access to the spark plugs and thats that?

I already have the silicone so I might as well put it in there. I was going to cut the shaft as well but maybe its not necessary?

 

Thinking about this, I seem to recall that there were quite a few examples of Marelli caused fires in Ferrari V-8s where they ran as two 4 cylinder units, and perhaps V-12s as well.

The Porsche dual plug, isn't going to suffer the same kind of failure because you are still going to get combustion, just not maximum efficiency combustion.

Additionally, the Ferrari is just a poor comparison. The risk of Marelli fire is from driving a XJS beyond the limits of proper maintenance. The number of XJS's that were driven well beyond proper maintenance standards, versus the number of Ferraris done so is a huge ratio.

 

Not sure which model you are referring to, but the 993 distributor is actually a side by side unit with a belt drive. I understand both sides of the marelli discussion, and will stay out of it

 

The way I see it is why do modifications that are not needed, spend the time and maintain the system correctly and the car will not burn

This is Porsch MArelli

 

That porsche rotor is a completely different design. Those are points.

I used the silicone, though I did not cut down the shaft. It may have been a good idea to do so. Hopefully I do not run into issues. Though, it apears everyone who has used any silicone at all has not run into a fire yet. Whether that is becuaes they used the silicone or because they are more on top of the maintenance from that point on will not be known. I will definitely swap out the plugs and wires along with the cap and rotor every 20k.

 

Anyone looking for a replacement this seems like a good price

Ferrari 400 - Jaguar V12 Distributor cap and rotor JLM 1909 1911

 

SNG Barratt has a good quality replacement cap they have manufactured in the UK available at very reasonable price.

 

Hoodun:


From a generic point of view, that distributor cap and rotor look to be in fine shape. The button is clean and undamaged. No signs of excessive arcing on each tower or on the rotor.


Agree, slap 'em on.


I've read of the silicon as added insulation. I've my doubts as to it's effectiveness.


But, a whole lot of necessary arcing going on in a somewhat limited space.


Carl