Guide | Technical
Info | Maintenence
| Reader's Reports
Disclaimer: any information provided here is used at your own risk. I
accept no responsibility for any damage you may do to yourself, others
or you car. Having said that I thoroughly recommend getting yourself the
Haynes owners workshop manual for the 924. It's
the best publication of it's type for the car, oh and also make sure you're
on friendly terms with your local porsche parts interpreter and wrecker,
they can save you both time and money with their useful information.
Updating your "kettering points" ignition to electronic
The "points" type ignition found in early euro (and US?) spec 924's, can
easily be replaced by a "Hall-Effect" electronic ignition system. "Ignitor"
make a conversion unit that replaces the points and best of all (unlike
similar systems like the Crane-Allison) is completely housed within the
distributor cap. It cost me AUD$180 but I never have to touch points again!
While your at it check you distributor vacuum advance unit. Follow the
vacuum hose from the distributor to the intake manifold. Unplug the hose
from the manifold and (with the distributor cap off) suck on the hose,
the points or hall-effect sensor should move. Replacing my broken advance
unit fixed a number of ignition and performance hassles I was having with
the car and at AUD$36 it's an easy and cheap fix.
Fixing that broken odometer/trip meter
I've lost count of the number of cars and stories I've heard about broken
odometers in the 924 and early 944's. The fix is quite easy. It involves
removing the Speedometer (quite difficult), opening it up (quite easy)
and supa-gluing a little plastic gear (dead easy!). The example I give
here is from my experience with my car (a '77 right hand drive) it should
be the same for most other models.
You'll need: 1 phillips head screw driver, 1 small flat bladed screw driver,
small hands (not like mine!) and lots of patience!
1) Sitting in the drivers' seat reach under the dash with your right hand.
Locate the back of the tachometer and gently push it out steadying it
with your left hand. (It'll just pop straight out).
2) The tachometer has three wires attached to the back as well as two
light globes. Remove the two light globes by just pulling them out (now
is a good time to replace the bulbs!). Pull off the three wires taking
note of which pin they come off (there are four pins!) on my car they
black, blank, green and brown (looking at the back of the tacho from left
to right) brown is intrument earth, green is feed direct from the distributor
and black is (I think) another earth (DO NOT CONFUSE the wires!)
3) Remove the two phillips head screws securing the dash surround, but
don't remove the surround, you only need to be able to move it a little.
4) With your right hand through the tacho hole gently push out the speedo
a short way. This should be enough for you to feel around and unscrew
the speedo cable (it may be tight!).
5) If you can't unscrew the cable don't worry, next remove the wire and
three globes from the back of the speedo. (one brown earth, two illumination
globes and one indicator globe).
6) With your left hand under the dash feed the speedo cable out while
pulling the speedo out with your right hand.
7) Unscrew the cable now if you haven't already.
8) The speedo should now be free, work it out of the dash (it may be tight!)
9) Using the small flat blade screwdriver prise off the lip around the
speedo bezel, don't worry if you bend it you won't see it from the front.
10) The bezel comes off with a "snap" and with it comes the glass (plastic!)
and another seal.
11) Remove the two screws on the back of the speedo and work the mechanism
out of the case.
12) The broken plastic gear is located on the end of the shaft holding
the odometer numbers. If it's still there you can just supa-glue it on
the shaft. Check before you glue that it's all working by turning the
cable drive and confirming that the numbers are going around. I found
that moving toward the end of the shaft worked quite well.
13) Reassemble by reverse order.
14) Replacing the speedo is quite tricky. I found that the following worked
best for me.
-Work the speedo back only a short way into it's hole so you still have
access to the back.
-Attach the left hand globe and screw in the cable.
-Push the speedo back in (but not all the way) I needed to guide the cable
with my left hand from under the dash and push quite hard (it's a VERY
-with the speedo almost home, woking through the tacho hole, I put back
the indicator globe, the earth wire (brown, goes on a pin on the speedo
body) and then the right illumination globe (you changed the globes right??)
-Push the speedo firmly home.
15) Before putting back the tacho confirm the lights and indicators are
working:take care that no tacho wires are shorting when switching on the
16) If all is well replace the tacho taking care to put the wires back
in the right spots, and push it home
17) Replace the dash surround and retaining screws
18) Fire her up and go for a test drive!
Changing the timing belt
How old is your timing belt? Don't know? Then replace it NOW! Changing
the belt is easy and unlike the 944 you don't need any expensive tensioning
1) remove the timing belt guard-3 bolts 2 at the top and one in the centre
at the bottom.
2) remove any drive belts (ie. alternator, power steer etc)
3) rotate the engine to No.1 TDC using the timing mark on the flywheel
[See Right] (the mark varies for US and euro engines so check which one
and the mark on the back of the top cam drive pulley (it lines up with
a pointer on the cam cover) [See Left]
4) using a large spanner and a socket wrench, loosen the small bolthead
on the tensioning pulley (mounted on the water pump) and gently rotate
the pulley (with the large spanner) to release the tension from the belt.
5) the belt can now be removed.
6) replace the belt making sure it meshes properly with the pulley's the
bottom pulley can be a bit tricky to see a torch will help.
7) Again using your large spanner turn the tensioning pulley until the
belt is quite tight.
8) Check the tension by twisting the long side of the belt with your fingers
through 90 degrees. You should just be able to twist it that far.
9) using your socket wrench tighten the retaining belt.
10) check that the engine is still at TDC. Using the mark on the camshaft
drive pulley and on the crankshaft. Sometimes you can move the timing
while tensioning the belt. I usually rotate the engine through a full
revolution by hand then re-check the timing marks to make sure everything
11) replace your accessory drive belts and tension them (now is a good
time to fit new ones!)
12) replace your cam belt cover (you can leave this till last in case
you make a mistake!)
13) start her up (if you like you can check you ignition timing with a
strobe although if you didn't muck anything up you won't need to) if you
mucked up the timing marks then either i) the engine won't start or ii)
it will run really rough or ping like crazy (if you're one notch out).
Re-align the engine to No1 TDC and recheck the timing marks again!
Adjusting early drum brakes
If you have an early (pre mid 77) 924 you may have non self-adjusting
drum brakes. They need periodic adjusting (when the hand brake doesn't
work so well or you can feel the brakes fading a little)
1) Park the car on a level, flat hardstand
2) block the front wheels securely
3) place the car in neutral and release the hand brake
4) using a large trolley jack raise one rear wheel
5) for safety you can raise the entire back end and place on chassis stands
6) on the backing plate are a number of holes (covered by rubber seals)
remove the seals. the inner two hide the adjusters (one for each shoe)
and outer two are inspection holes so you can check the wear.
7) using a long flat screwdriver turn the adjusting wheel until the road
wheel no longer turns freely by hand, then back the adjuster off a little
until the road wheel turns freely by hand.
8) repeat this for the other adjuster
9) replace the rubber caps and repeat for the other side.
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