924Board.org

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

Hi all,

finally got my hands dirty and replaced the alternator earth strap with the official part bought at the OPC, and removed my fudge. First pain was that the thread into the alternator seems to have worn out - was very loose, so I used a slightly longer bolt with an extra washer and it tightened, phew! (otherwise its on with the spare alternator!)

anyway, sorry for digressing! Main point of the post is something I've hit before and just wondered if its a common thing.

The belt length specified for my car ('85 UK n/a no power steering/aircon or any of that) seems too short. The last time I changed it I had to loosen the alternator to its shortest setting and still had to lever the pulle on with a screwdriver to get it on. Then the belt runs perilously close to the alternator bushing.

Each time I've bought one at either German/Swedish/French or Eurocarparts its been the same one, so I ordered the belt from the OPC (not too much more expensive) and the only difference seems to be the width, the width of the OPC one is 9.5 whereas all the others (Bosch etc) seem to be 10. Being slightly thinner it was easier to get on, but again there's no point tensioning it as its too tight with the alternator fully across.

I wondered if something is not fitted correctly, or whether I actually have an engine from an older model...

any suggestions?
_________________
1998 BMW Z3 2.8 arctic silver & red

1981 168HP 931 S2 blue/tan leather - SOLD

1985 121HP 924 2.0l na modded - SOLD!
1992 968 lux SOLD
1989 944 2.7 lux SOLD

Ozzie · Posted: Thu May 04, 2006 10:59 pm Post subject:

Sounds just like the drama I go through to fit mine.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Smoothie · Posted: Thu May 04, 2006 11:46 pm Post subject:

Different sized pullies were used, so it's possible to have the wrong size belt for your pulley -
http://www.924board.org/viewtopic.php?t=6141

TJ couldn't find a 10x, but found an 11x915 belt fit fine - http://www.924board.org/viewtopic.php?t=13272&&start=45
-Should only change belt width as a last resort though, because a too narrow belt might sit too low in the pullies and slip, while a too wide belt would sit higher-up and be more likely to come off.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

Having read the post Smoothie pointed me at (I did search before posting honest!) it would appear that I have an old pulley, but I might like to measure it at some point to confirm that, but there also seems to possibly be a reason to have the smaller pulley (apart from proper tension) so I may see if my spare alternator (from an '81 931) has the different pulley...
_________________
1998 BMW Z3 2.8 arctic silver & red

1981 168HP 931 S2 blue/tan leather - SOLD

1985 121HP 924 2.0l na modded - SOLD!
1992 968 lux SOLD
1989 944 2.7 lux SOLD

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

The smaller pulley is the newer one, and should have come on all cars built 80 and later.

Switch was made to the smaller pulley at the same time that a higher rated (more watts) defroster was added to the rear hatch glass. the smaller pulley allows the alternator to spin faster sooner and generate more current (amps) at a lower engine speed.