Is there a general consensus as to how long the Marelli rotor will last,
either in terms of mileage or months, before pushing an XJ-S flamb�
envelope? How often are folks on the list changing their rotors and
ignition caps?
TIA,
Don K.
Is there a general consensus as to how long the Marelli rotor will last,
either in terms of mileage or months, before pushing an XJ-S flamb�
envelope? How often are folks on the list changing their rotors and
ignition caps?
I have had a new cap+rotor in for a year now. I plan on checking the condition
of the rotor and cap at least once a year, more if I am working in that area.
The old cap (the PO’s, don’t know how long it was in there), was in very good
shape, and I have saved it for a spare/back-up?. The quality of the Marelli
cap (not the aftermarket) is very high, I think we can get quite a few years
out of it. The rotor, I will probably replace every year, even at $70
something a pop. The peace of mind is worth that. My old rotor (PO’s) showed
signs of a carbon type deposit on it, along the ramp leading to the lower
contact. These deposits will determine how often I replace my rotor. I posted
to the list last year about this (with photo’s). If anyone is interested in
seeing this rotor I think I still have the photo’s on my hard drive, if not I
will take a few more. These deposits might be the cause of the problem?
I now trust the Marelli system, not so when I first heard about the rotor burn
through problem. I am prepared to deal with it if ever happens, I hope!
Al Askevold
90 XJ-S CONV.
The Ozarks, USAFrom: “Don Krysakowski”
Don Krysakowski wrote:
Is there a general consensus as to how long the Marelli rotor will
last, either in terms of mileage or months, before pushing an XJ-S
flamb� envelope? How often are folks on the list changing their
rotors and ignition caps?
Hmmmm. All things considered, perhaps a better idea than replacing
every x miles would be to carry a spare and be prepared to replace
the INSTANT one fails.
I suspect the rotor life is strongly related to plug gap – the
bigger the gap, the shorter the rotor life.
– Kirbert
Are you talking about “carbon track” (white)?
The rotor may be cheapish, but the distributor, especially if we have to buy it from jaguar, is in the $400s I believe. Anyone sells the original distributor caps other than the dealer?
Chris,
90 xjs.--------
My old rotor (PO’s) showed signs of a carbon type deposit on it, along the ramp
leading to the lower contact.
Al Askevold
90 XJ-S CONV.
The Ozarks, USA
How will someone know if the rotor fails? You mean wait for the car to stop firing because the rotor contacts caused a short, or lost their ability to drive the distributor cap due to carbon deposits and wear? Isn’ t that kinda too late?
I like it though. No one single day of the rotor’ s life is wasted this way.
Chris,
90 xjs convertible with marelli and quite used-up rotor.>Hmmmm. All things considered, perhaps a better idea than replacing
every x miles would be to carry a spare and be prepared to replace
the INSTANT one fails.
– Kirbert
Are you talking about “carbon track” (white)?
The rotor may be cheapish, but the distributor, especially if we have to buy
it from jaguar, is in the $400s I believe. Anyone sells the original
distributor caps other than the dealer?
No, the carbon like deposits are a grayish color on the ivory colored rotor.
Cheapish is not the right word, they are expensive and are of a high quality.
Just about any source can get these Marelli parts, just be aware that they are
boxing the cheaper (non Marelli) parts in the “green” Jag boxes. If you pay for
the Marelli make sure you get the part you paid for.
Al Askevold
90 XJ-S CONV.
The Ozarks, USAFrom: christky@bellatlantic.net
christky@bellatlantic.net wrote:
How will someone know if the rotor fails?
Everyone who’s had it happen reports you can’t miss it. The car
suddenly has less power than a Subaru, and not only needs to be
floored to maintain speed but will often downshift to 2nd.
The problem is not that you don’t know it; the problem is that it
still RUNS, and there is a significant percentage of the American
driving population that will drive a car every last foot it will move
under its own power before seeking repairs.
You mean wait for the car
to stop firing because the rotor contacts caused a short, or lost
their ability to drive the distributor cap due to carbon deposits and
wear? Isn’ t that kinda too late?
The failure is that the A bank shuts off. Car still runs, and has no
damage – if you stop IMMEDIATELY. If you keep driving, your
problems will multiply within seconds.
I like it though. No one single day of the rotor’ s life is wasted
this way.
AFAIK, nothing else in the car is damaged when the rotor fails. If
true, driving until it fails and then swapping out the rotor roadside
should work fine. Can’t wait for a nice spot to pull over, though;
if you’re sitting in the left lane waiting for the light to change
when it fails, I’d suggest either fixing it THERE in the midst of
oncoming traffic, or shut it down, wait for the light to turn AND for
a clearing in traffic, and start it just long enough to drive off the
side of the road.
There is an option, described in the Book, for shutting off the fuel
to the A bank when the ignition on that bank fails. Easy to do, just
splice a switch into the wires to the injectors. That would allow
you to take more time to pull over to replace the rotor.
– Kirbert
The failure is that the A bank shuts off.
– Kirbert
Thanks. I do not understand why the A bank shuts off (passenger-side). Is this something wired internally to the marelli? Why can’ t the B bank shut off as a reaction to a rotor failure, or both banks shut off together, or no shut off at all? The rotor serves both banks since it has 2 contacts inside. Why is only the A bank affected? What logic is behind this?
Thanks
Chris,
90 XJS Convertible (with Marelli and a miserable-looking rotor)
christky@bellatlantic.net wrote:
The failure is that the A bank shuts off.
Thanks. I do not understand why the A bank shuts off
(passenger-side).
Correction: It is the A bank that shuts off. It is not necessarily
the passenger side, since that could mean either A bank or B bank
depending on which part of the world you’re in.
Is this something wired internally to the marelli?
No, it’s the rotor that fails.
Why can’ t the B bank shut off as a reaction to a rotor failure, or
both banks shut off together, or no shut off at all?
Because it doesn’t. The Marelli is two separate 6-cylinder ignition
systems, and it’s the A half of the dual-level rotor that fails.
The rotor serves
both banks since it has 2 contacts inside. Why is only the A bank
affected? What logic is behind this?
What can I say? It’s the A contact that shorts to ground, not the B
contact.
– Kirbert