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24V Cosworth Scorpio
After a series of electrical silliness, such as instrument resets on startup,
flickering battery light and a complete electrical blackout, I checked the
battery with KwikFit, who discharge tested it. When the needle showed no change
after 20 seconds it was clear that the battery was okay, which left the
alternator as the prime suspect.
First of all, there is some confusion in the parts books for the Scorpio and
it's as well to give you what information I have gleaned first so that you are
better placed to get the right replacement, which is more than I managed. There
are three types of alternator on the Scorpio range -
| DOHC |
Bosch KC 90 amp |
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| All V6 |
Magneti Marelli A1271 - 100 amp |
| Diesel |
Magneti Marelli A127 70 amp |
For the 24V you are looking for a [looking from the front] LH mounted alternator
with about 48mm between centres on the mounting holes. The unit I was given
first looked correct, but had 60mm between the mounting holes and would not fit
the solid bracket. Take a ruler with you when you go to the dealer and measure
the distance between centres shown below, and that the rear mounting hole is on
the right for the LH mounting.
The second alternator I was offered looked exactly right, but it was set for a
RH mounting. I could have taken it, but unbolting the rear casing and moving it
round 90 degrees would have meant invalidating the warranty, so I left the
alternator behind and refitted the old one for now.
When you first look down the front of the engine behind the radiator and fans,
you suspect that there won't be enough room to change the alternator - but in
fact there is with care.
First - and this is most important - I disconnected the battery and tucked the
positive lead away so that it can't creep back to the terminal. Be careful to
use a short spanner and great care when removing the battery connection, the
bonnet hinge is very close.
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| Then I needed to release the auxilliary drive belt. I found that
I did not need to touch the AC compressor belt, I just released the left hand
belt and pushed it out of the way. It's very easy to remove - if you know how.
The left hand drive belt runs from the crank pulley up over the tensioner and
down again to the alternator, then up over the power steering pump and straight
to the water pump, then down to the crank pulley. The tensioner contains a large
coil spring and requires some muscle, but space is restricted between the
tensioner and the electric radiator fans. Ford suggests using a ring spanner
from underneath, but I could not budge the tensioner at all, so I used a short
17mm socket on a small ratchet augmented with a piece of square steel tube to
give extra leverage, turning clockwise, and the tensioner unlocked with a click
and released plenty of slack to pull the belt from the alternator pulley. I then
gently removed the clockwise pressure and allowed the tensioner to release
fully. If I were changing the belt I would need to remove the AC drive belt as
well, but here I left it in place. |
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| Reaching underneath without jacking the car up I could reach the
engine undercover quite easily. There are four T30 torx head screws for the
engine cover. They were removed and the cover pulled away. I then used the
cross-member and a 3 tonne jack to lift the car and placed it on axle stands. It
was not necessary to raise the wheels right off the ground to give plenty of
room to slide under. The alternator is secured with a through bolt and nut at
the top and a single bolt underneath. In order to release the nut from the top
bolt, I found it necessary to remove the o/s exhaust manifold heat shield -
three 10mm bolts on the top and two underneath. The heatshield was drawn away
and this provided just enough room for a small ratchet and 13mm socket for the
nut, with a larger 13mm socket on the front to stop it turning. The bolt then
free, it can be withdrawn as far as the radiator fan housing where it seems
trapped. I left it there for a moment, then went underneath to remove the lower
13mm bolt. The two power connections are then removed using a very small ratchet
at 10mm socket. I removed the large power wire from the top, which is a 10mm
nut, and then removed the lower one from underneath. This is also 10mm, but is
captive with the connector. |
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At this point the alternator is free to move, but the upper bolt
is trapped. Looking up from underneath you can see that the radiator fan housing
is secured with a slide and a single 10mm bolt in a slot. The right hand bolt is
just beneath the top radiator hose. I loosened this off and then slid the
electric fan housing upward to free the alternator bolt. The alternator can then
be levered from the mounting and drawn round the power steering pressure hose to
the ground. |
On the right is a view of the alternator from underneath. On the
top right corner is the radiator and the black pipe beneath the alternator is
the power steering pressure pipe (this is the new one installed to stop the
vibration at parking speeds. You can also see the Power
Steering Pressure Switch which advises the EEC-V of
impending load from the Power Steering. The bottom fixing bolt can be
clearly seen. There is a glimpse of the Cosworth alloy sump beside it. There is
just enough room between the pressure pipe and the radiator to fiddle the
released alternator through.
Having looked at the new alternator it was then I discovered that it would never
fit. The alternator bracket is rigid steel and the bolt holes must be in exactly
the right place or the unit would never fit. Good thing I checked it before
offering it up!
The bracket is black metal here behind the PS pipe - unless the holes on the
alternator match exactly the alternator is useless. |
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I returned the new one to the motor factor and then we examined
three more which should be right - no joy. One had the correct bolt centres, but
was for a RH fitting!!
Nothing for it but to put the old one back until I could source the correct
replacement.
I tapped the alternator bolt collar gently so as to loosen the alternator on the
bracket in the engine, and then squeezed the alternator through the gap and
offered it up to the bracket. Still working from underneath, I loosely installed
the lower bolt to the bracket so that the alternator could not fall, but was
roughly in the right place. Using the lower bolt as a fulcrum, I moved the
alternator about from the top with the through bolt in the top hole so as to
feel for the lining up. It is tricky here, because the radiator fan housing has
to be pulled up at the same time to allow the slack for the bolt to line up.
After a bit of struggling and bad language, the bolt slipped in and I put the
nut and its washer on the other end. Both top and bottom bolts are torqued up to
25Nm. I then reinstalled the alternator connections, torque 24Nm. |
| The radiator fan housing needs to be retightened.
Then I reinstalled the drive belt. Using the long bar on a small ratchet makes
it very easy, despite the limited clearance, and I recommend this method. I
checked that the belt was properly seated on all the pulleys. Done. |
 I lifted
the car off the stands and lowered it. I replaced the exhaust heat shield,
(bolts lightly tight) and then reconnected the battery and replaced the battery
cover. I ran the car for five miles so that it could re-learn the engine data,
and then checked for any error codes: none.
I entered the pin code for the radio - worked first time.
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And the end result? Not altogether a waste of time. I have used the car for
three journeys since and the electrical gremlins have gone - at least for now.
There has been no flickering light, no instrument resets, nothing. Perhaps there
was a loose connection? I will wait and see.
CHARGE WARNING LIGHT
Incidentally - do not assume if the alternator is not charging that the battery
light will warn you - it won't. The charge warning light will not illuminate at
all if the alternator diodes or regulator circuit goes open-circuit. So check
the lights in the instrument panel at start-up, if there's no battery light
there's no power going into the battery!
Tools Required
T30 Torx bit
17mm short socket - extension bar
Short 1/4" drive ratchet, 10mm, 13mm sockets
Torque wrench
Trolley Jack, 2 axle stands
NB The charge warning light flickered the very next day, so I
went to Ford, where I purchased the correct re-engineered alternator, which cost
£125. It was installed in an hour, which shows how much difference rehearsal
makes to any job!
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