924Board.org

[caswah]

Euro 1981 924 Coupe 125HP.

The stupid mistake:
Forgot to secure the distributor cap before starting

Under the distributor rotor, there is a metal ring with 4 pins bent 90 degrees down (pointing down into the distributor housing). As the distributor rotor rotates, these 4 pins pass tightly by 4 static pins.

As the cap was not secured, the metal clamps normally holding the cap were loose and in the way of the 4rotating pins. 2 of them were damaged, not badly but slightly bent. Since then she hasnt started.

Tried to understand what the pins do and how large the gap between the rotating 4 (the rotor) and the static 4 (the stator) should be, but found no info. Haynes says "check for a visible gap", I did so, bent the rotors back in position and made sure the rotor did not touch the stator.

I reinstalled the distributor, set the ignition timing carefully but she wont start. Tried adjusting the distributor position (the timing) slowly whilst revolving the engine with the starter, at some positions it sounds like its going to start (nice ignition sounds) but it simply doesnt.


So the only thing different now from when she was running perfectly is that the distributor rotor arms have been bent and rebent. Is this causing it all ?

HELP !
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Euro ´81 924 - Interior being restored

[gohim]

The four shutters (two of which you bent) pass in a slot blocking a magnetic field.

The two sides of the slot have delicate electrical coils in them.

I guess is that when the shutters were bent, they made contact with the plastic wall parts (a single assembly called a "hall effect sensor", and damaged the sensor.

The sensor will need to be replaced. The sensor costs about $75-$100 here in the US. When mine died, I took the entire distributor to a Bosch Authorized Service Center where it could be tested and repaired.

You could also look for a used replacement distributor.

[ideola]

[Ozzie]

IIRC the euro model was the same throughout the range except for the points type.
my '84 na had a 477 905 206
another number on it was 0 237 002 054
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[michi924]

Time for a new distributor. I recommend ebay.co.uk becouse you are in Sweden.
If you buy it online, remember to ask if it's a ignition pick-up distributor what they are selling. Ptobably the second reference Ozzie wrote.
The ignition pick-up is what tells the ignition module when to trigger the ignition coil.
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Porsche 924 NA Euro.

[caswah]

Thanks for your help =)

My distributor has the Porsche OEM Nr 023 700 2054 and the VW Nr 477 905 206. After a couple hours on the net I found out there is a Bosch-number for exactly this distributor. Its 0986 237 102 as well as an EAN: 316 514 314 89 78.

Hope the numbers are useful to someone.

Ive contacted Bosch Sweden to see if they can help out, waiting for their reply. Think my plan is :

1) Take another look at the dist, set the timing again, check wires again etc
2) Take it to a Bosch authorized repairman
3) Buy a new one

Ive looked around for a used one, but since I need one with the exact serial number its wuite hard. Ive found two matching my numbers but they are sold from dissembly shops for 100£ (!!). And they are 28 years old, dirty and without running guarantee.. I can get a brand new one from the US for around 230£, so Im not paying 100 for a dirty old bastard.

Will try to deal with the dist myself first though.
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Euro ´81 924 - Interior being restored

[RC]

The numbers are only useful if you wish to pay megabucks to a dealer. The only electrical part in these is a coil of wire, the pickup coil. They`re a common part, only about US$30 - 40. Check by measuring resistance, IIRC should be between 600 ohm and 1.2K, specs in manual. If that`s OK you likely have another problem, although they do go intermittently open circuit.

Ignore comment about hall effect sensor as they were only used in US and perhaps Ca, not in Euro/ROW. The 4 prong star is called a reluctor and <$10. They should all be straight, aligned at 90* and set with an air gap 0.2 - 0.3mm, about 0.010".

Heaps more info using SEARCH:
http://www.924board.org/viewtopic.php?p=258168&highlight=reluctor+variable+coil#258168

http://www.924board.org/viewtopic.php?p=202528&highlight=reluctor+variable+coil#202528

http://www.924board.org/viewtopic.php?p=210651&highlight=pickup+coil#210651

[caswah]

Thanks again.

I fixed it. Bosch sweden sent me an exploded view of the distributor, I took it apart, cleaned it and bent the stator legs even more until there was a gap of almost .5 mm

Reinstalled, timed the engine again and then she fired up instantly.

After running smoothly for 15 minutes it died. I found a piece on the ground. It was one of the L-shaped steel legs holding the engine to the chassis.

Because of the violent vibrations, the timing belt was jammed and ripped off. Im so sick of this. There is absolutely no rust anywhere else in the car except for in that engine attachment. Ripped timing belt is, as you all know, a bit like ripping someones main artery : bad bad idea.

So from one problem to another. Are the valves screwed? The valve lifters ? Is my 924 crap?

Dont want this.
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Euro ´81 924 - Interior being restored

[ideola]

The NA motor is non-interference, so you shouldn't have any worries with valves or lifters. Just replace the timing belt and the tension roller, and you should be back in business. You might consider doing the water pump while you're at it, but not a requirement.
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erstwhile owner of just about every 924 variant ever made

[caswah]

OK, that was at least some comfort.

But I still have to replace the engine mount that came loose. That was a bit of a surprise, almost no rust whatsoever in any other place and this 2-3mm steel was rusted all the way through and fragile like an egg..

Is there any chance that I can replace the mount without lifting the engine out?

And what does non-interference mean ?

Thanks again.
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Euro ´81 924 - Interior being restored

[ideola]

[!tom]

In an interference engine, both the pistions and the valves occupy the same space, but at different times.

In a non-interference engine, this is not the case.

Therefore, if the pistons and valves become out of time in an interference engine, the pistons will bend the valves, and the valves might break the pistons, as it is problematic if the pistons and valves attempt to occupy the same space at the same time. This is not a problem in the non-interference engine, as the pistons and valves never attempt to occupy the same space at the same time.

The 924 normally asperated engine is the non-interference design, whereas the 924 turbo, or 931 as it is commonly referred to here, is. Also, the 924S, the version of the 924 with the engine from the 944, is as well. This is a completely different engine than what the earlier 924 and 931 use.

So, 3 engines in the 924 variants.

924 - not interference
931 - interference
924S - interference
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78 924 NA
5-lug