Jaguar XJ-S. Service manual — part 145

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metal fan on the front, and another fan inside the housing at the rear. These alternators are rated at 85 to 105 amps in
stock form, can be rebuilt to put out 140 amps, and charge like a sumbitch at idle. They are all internal-regulator type;
apparently they assume you know that, because none of the books or catalogs tell you.

I know you don’t think the physical size is a big deal, but let Arthur Blackwell improve your mind: “the alternator is
much smaller physically and did not require dropping front suspension pieces to put in place.”

The CS130 alternators come with some interesting variations in main power connections. Some have a basic stud,
while others have a protruding rectangular block that a screw is run through crosswise. Whatever, it shouldn’t be
difficult to finagle a connection to the battery in the XJ-S.

The CS130 comes with a special regulator connector: a rectangular block with four pins in it -- one large one and three
smaller ones. The big one is the sense wire, similar to terminal 2 on the earlier GM alternators. You don’t need to
connect it to the main power connection three inches away because GM has thoughtfully done that for you internally.
Apparently, if you connect up a sense wire, it will override the internal sense connection. Hence, it is an optional sense
connector; you can connect it to the main bus for optimum performance, or you can just forget about it and it’ll work
fine.

The small pin right next to the big one goes to the ignition switch on cars without a dash indicator light. The middle
small one goes to a dash indicator light on cars so equipped. It’s not known what the farthest small pin is for, perhaps a
tach connector.

For clarity: you only need to connect up the main power cable and connect the middle small pin in the plug to the
existing NB wire in the XJ-S to get the CS130 alternator to work. If you get the plug with the alternator from a
junkyard, it’s probable the plug will only have that one wire!

If you don’t get a connector with the alternator, auto parts shops sell a variety of connectors to fit the CS130 regulator
socket. You will need to get one from somewhere -- generic spade terminals won’t work here. There are plugs
available with four wires, one to each pin. There are plugs with only three wires. There are adaptors (short harnesses
with a connector on each end) for retrofitting the CS130 into cars without dash indicator lights that originally had the
earlier alternators with 2-wire connectors. And there are adaptors for retrofitting the CS130 into cars with dash
indicator lights that originally had the earlier alternators with 2-wire connectors. Three out of these four will work on
the XJ-S (you won’t want the adapter for cars without dash indicator lights), so choose the cheapest one of the three. If
it’s the adapter you buy, just cut off the 2-wire connector and use the CS130 connector end.

If the CS130 in hand has the connections in an inconvenient position, the pulley can be removed with a 24mm socket
and an impact wrench, then the case separated by removing the three bolts using an E8 Torx socket. Then the front
case can be rotated to any of three positions and the bolts reinserted. Since the front case includes all the mounting
lugs, this effectively rotates the rest of the alternator, including all the terminals on the rear end, in 120º increments.

Note that GM alternators can be fitted with either a single-groove pulley or several different widths of multi-groove
pulley -- and of course most modern GM cars come with serpentine belts, so finding an alternator with a single-groove
pulley in the junkyard might be difficult. The pulley from the Lucas alternator will not fit. However, finding a single-
groove pulley for a GM alternator shouldn’t be too difficult or expensive, and they can be swapped out in a minute.

There are some reports that GM alternators all have problems with the rear bearing. SI units came with a needle
bearing, apparently a source of trouble. The CS130 comes with a ball bearing at the rear, a considerable improvement -
- except that they used too small a ball bearing. The CS130 has also developed a reputation for lack of durability,
apparently frying something in the electronics every 50K miles or so on the American cars they are fitted on. This
being an American product, there are aftermarket fixes: J. C. Whitney (page 691) offers a “Quick Start ‘Iceberg’”
rebuild kit, 81xx5780U, which provides improved rectifier cooling and a larger rear ball bearing for the CS130
alternator. If you are paying good money for a rebuilt alternator from a reputable shop, you may want to insist upon
such improvements at the outset.

J. C. Whitney also offers a kit, 81xx5781B, to convert the CS130 to 140 amp capacity. This is not necessary with a
stock XJ-S, but if you’ve added loads such as an electric radiator fan or a big sound system, it’s something to consider.

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Besides the SI’s and the CS130, GM also offers the CS130D, described on the Oakville Starter Alternator Ltd. “Tech
Talk” web page: “The CS130D is the revised version of the CS130 and uses the same alternator connections although
the connector has been slightly modified to reduce corrosion. Some GM vehicles as early as 1994 may have come
equipped with this alternator. The joke in rebuilding circles is that the "D" in CS130D stands for "Different" because
although the CS130D is supposed to be a close cousin of the CS130, internally they are totally "Different" - there are no
interchangeable components. In reality the "D" stands for "Dual Internal Fan". The CS130 also had dual fans - one
external (behind the pulley) and one internal (inside the alternator near the rectifier). In the CS130D, both fans are
internal - there is no external fan behind the pulley. This is the easiest way to distinguish the two alternators.

“One of the new features on the CS130D is the alternator's internal temperature sensor. The regulator will sense the
alternator's internal temperature and shut the charging system down if the unit reaches 280°F. The dash light will also
come on. This of course will prevent overheating and prolong alternator life. This also means that if this alternator is
overloaded (by a bad battery or an ear-bleeding stereo, etc.) it will shut off! No longer will roasted alternators be
returned to us for warranty. The downside of this feature however is that diagnostic problems could occur. Imagine, a
hot July day stuck in traffic - air conditioner is on full. Suddenly, the alternator stops charging and the idiot light comes
on. The customer pulls off the highway into your shop and sits for 45 minutes before you can check it. When you
check it you find that the alternator charges fine. The regulator had shut the alternator down after it exceeded 280ºF;
once the vehicle cooled, the alternator started charging again. There is nothing wrong with the vehicle or the
alternator.”

In NW Florida in 1998, the price for a rebuilt GM alternator -- of whichever type -- was in the vicinity of $1/amp.
Actually a little less than that without core charge, but you might not wanna sell off your Lucas for the core value of a
Delco so you may prefer to pay the core charge.

Michael Aiken points out that if your car came with the Bosch 115-amp alternator instead of the Lucas, you might be
reducing your capacity installing a GM alt -- and the Bosch seems to be far more reliable than the Lucas, so you may
not be improving reliability significantly either. Of course you can opt for a GM alternator up to 140 amps.

ALTERNATIVE ALTERNATOR INSTALLATION: A non-Lucas alternator won’t simply bolt in where the Lucas
alternator comes out, so you’ll have to do something to mount it. The following sections describe several ideas for
installing alternative alternators -- all of which happen to be GM alternators. But the same ideas might apply to other
alternative alternator installations, even though details may differ.

GM ALTERNATOR INSTALLATION -- WHERE THE LUCAS WAS: One possibility involves making an entirely
new bracket to fit whatever alternator you choose. However, the existing alternator mount bracket is rather convoluted
and is involved in supporting the air pump as well, so it would be no simple task to fashion a replacement. It might be
worth it, though; the cost of a new Lucas alternator would pay for a GM alternator and a very expensive custom-made
bracket, and the next alternator replacement would be cheap.

Fortunately you can skip the fab work and just buy a new bracket. John’s Cars (page 715) offers a bracket to fit a GM
Delco alternator, complete with a suitable wiring connector. Their catalog number for it is GMALT. Michael Minglin
says, “A little pricey, but well-designed and went in without any problems.”

GM ALTERNATOR INSTALLATION -- HUNG OFF THE AIR PUMP BRACKET: It’s possible to hang a GM
alternator from the bottom of the air pump bracket instead of from the alternator bracket. The air pump bracket is steel
and can easily be altered to hold a GM alternator close enough to the original position that the stock adjuster can be
used. The attachment of the adjuster to the front of the engine is a block on a single bolt that can be loosened and
repositioned to accommodate the new alternator position.

Jim Schultetus describes the method he used: “the original alt bracket was removed along with the alt and a rough
dimension was taken from a reference point off the bracket to the alt pulley and from the front of the bracket to front
edge of the original Lucas pulley. With these dimensions the CS130 was positioned next to bracket and two straps

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about 1-3/4 inches long were made of 1/4 in. steel about a inch wide with a 3/8 in. hole drilled in one end of each.
These two straps then where bolted to the Delco alt and positioned on the original bracket tube of about a inch in
diameter. Using the original measurements taken from the Lucas alt in original position I welded the 2 straps to the
tube. Bolted bracket back to block, installed CS130 and used original tensioner setup and belt. Took about 1 1/2
hours.”

Another variation on this idea would be to bolt or weld steel plates to the surface of the flanges on the air pump mount
extending downwards, and drilling holes for a pivot bolt through them.

Here’s another idea for modifying the air pump bracket to hold a GM alternator that doesn’t involve welding: Drill a
set of holes for a second pivot bolt, this set close (very close) to the bottom edge of the bracket and between the engine
and the stiffening tube in the bracket. Swing a GM alternator from this pivot, spacing it back from the forward face of
the bracket the proper amount to align the belt -- about 3/4”. A “long lug” alternator (see GM alternator descriptions
above) would probably fit best. The only problem with this idea is that the alternator probably won’t be able to swing
through many degrees between hitting the air pump bracket on either side of the pivot, so you’d need to select exactly
the right length belt. A little filing here and there may permit a few more degrees of swing.

The Lucas alternator, using the GM alternator terminology, has the tensioner lug at the 2 o’clock position. Since the
various methods of supporting the GM alternator from the air pump bracket position the pivot outward and upward
from the original pivot for the Lucas, using a “straight across” (6:00 and 12:00) lug arrangement should put the
tensioner lug in nearly the same position as original.

Don’t just run a pivot bolt through the bracket and tighten a nut on the back side; you’ll distort the sides of the air pump
bracket. Insert the pivot bolt through the front flange of the bracket, through some spacers selected to provide belt
alignment, through the pivot lug on the GM alternator, through a washer , through two nuts, through a washer, then
through the rear flange of the bracket and into another washer and nut. First, snug up the rearmost nut, but don’t
overtighten it -- you don’t want to distort the bracket. Second, tighten the nut just forward of the rear flange back
against the forward side of the rear flange, so those two nuts are tightened down against each other with the rear flange
in between. Finally, after adjusting the belt tension, tighten the forwardmost nut forward, pulling the alternator lug
snugly against the forward flange of the bracket.

If your pivot bolt isn’t threaded the entire length, you may need to add some spacers between the back side of the
alternator lug and the nut that tightens down on it.

REPLACING THE AIR PUMP WITH A GM ALTERNATOR: If you happen to be using your car for competition or
other applications where the air injection system is unnecessary, ripping the air pump out and putting a GM alternator in
that spot to maintain tension on the A/C compressor belt makes sense. It looks especially attractive when you realize
that the mount schemes are similar; a small GM alternator will fit right onto the air pump mounting bracket, you only
need to add a few spacers on the pivot bolt behind it.

A short-lug CS130 alternator with a tensioner lug at 10 o’clock works just fine mounted on the air pump bracket in the
OEM location, and does not interfere with the tensioner clevis, radiator hoses, or thermostat housing. A CS130D
should fit just as well.

Alternators driven by V-belts, including the Lucas on the XJ-S as well as GM alternator applications using V-belts,
generally use a 10mm wide (15 series) V-belt. The air pump and the air conditioning compressor on the XJ-S use a
13mm wide (17 series) V-belt. If you install a CS130 alternator in place of the air pump and driven by the same belt as
the compressor, you need alternator pulley part number 24-1104. Other GM alternators probably need the same
pulley. Unfortunately, you’re not likely to find this pulley in a junkyard, but it can be ordered through any alternator
shop for perhaps $15. This pulley is 3-1/4” in diameter, which is larger than typical alternator pulleys for 10mm belts,
which means the alternator will turn slower -- which may have implications on charging at idle. That’s tough; this
pulley is this big for a reason, namely that a 13mm belt really shouldn’t be bent any tighter than that.

From Bernie Embden’s www site: “I was able to source a 3.25" wide belt pulley (1/2 inch) from Canton Racing
Products. At $32.00 US, this billet aluminum pulley cost more that the alternator, but it does look good.

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The tips of the cooling fan on the alternator might hit the upper corner of the front leg of the air pump bracket. To
preclude this possibility, slip the pivot bolt through the air pump bracket with a washer under the head, mark a
semicircle around the edge of the washer, and grind off the portion of the bracket outside this mark.

The pivot on the air pump is 3-3/4” long, but the pivot lug on a GM alternator is only 2” long. You can fill the extra
space within the bracket with a stack of washers if you want. If you want a more professional appearance, drop into a
bicycle shop; many 10-speeds use a 10mm rear axle and have spacers on the derailleur side of the rear wheel that will
serve quite well here. Or you can get some more of the spacers used by Jaguar on the banjo bolt at the top right of the
radiator; it’s part number CAC4559. All of the spacers should go behind the alternator pivot; with it butted up against
the front leg of the air pump bracket, the belt lines up perfectly.

The rear leg of the air pump bracket has a sleeve fitted where the pivot bolt goes through -- just like any other similar
bracket. This sleeve is intended to be pulled through the bracket leg as the pivot bolt is tightened so that the air pump
(or whatever) can be snugged up without bending the bracket itself. Make sure that your spacers are long enough that
this sleeve is not pulled all the way through the bracket and the nut contacts the bracket leg itself. In fact, you might opt
to push that sleeve rearward in the bracket before you start fitting spacers to give it more capacity to take up slack when
tightening down the pivot bolt.

Unfortunately, the pulley on an alternator is smaller than the one on the air pump, which moves the portion of the V-
belt between the crank pulley and the alternator up a little -- possibly right into the idler arm for the belt-driven fan.
David Osborne didn’t have a problem. “I did the CS130 alternator-in-place-of-air pump conversion with great success.
The replacement (shorter) belt (Dynacraft 59017) successfully clears the idler arm by about 3/16 inch.” Alas, others
haven’t been so lucky, and when you realize you’ve got interference there it can bring this pleasant little job to a
screechin’ halt.

To avoid this interference problem, it helps to mount the alternator with its centerline as low as possible. That’s why
you want a CS130; its small diameter keeps the centerline closer to the mounting bracket. You also most definitely
want the short-lug version.

The 24-1104 pulley may also help with the interference problem. Using this slightly larger pulley will move the belt a
hair away from the interference.

You’ll need to figure out what length V-belt you’ll need; with the CS130 alternator and 24-1104 pulley, the 59017
mentioned by Osborne above (or a 17590, same difference) works fine on the author’s car with no belt-driven fan and
hence no interference concern. Going to the long side helps with the interference problem, as swinging the alternator
farther away to tighten a longer belt also moves the belt farther away from the idler arm. Going too long, however, will
bring the alternator close to the side of the engine compartment and possibly cause a whack when the engine twists on
its rubber mounts. That’s another reason to choose a CS130; it’s small size allows you to pivot it farther outward
without contacting the fenderwell.

Once you find a belt length that works, John Napoli says, “Note the number (length) of the new alternator belt and
scratch it into the fender of the car.”

You might also find that going with a different length fan belt may help the interference issue by moving the idler arm
out of the way. Of course, the best way to avoid the interference issue is to toss that belt-driven fan and idler hardware
over the hedge and install an electric fan as described on page 219. As long as you’re installing that big-amp GM
alternator, why not put it to good use?

With a CS130 with the tensioner lug at 10 o’clock, the existing tensioner arrangement for the air pump will work just
fine. If you use some other configuration and the alignment of the tensioner bracket gives you any trouble, take the
tensioner bracket off the front of the right bank and replace it with the tensioner clevis formerly used with the Lucas
alternator at the bottom right corner of the engine. This will require a 1/4” thick stack of washers under one end since
the alternator tensioner clevis was designed to sit on an uneven surface.

See page 312 for removal of the rest of the air injection system.