924Board.org

[Johnny_Haywire]

Have any of you guys ever come across this? My positive terminal on the new battery gets hot while the car is running. Like...real hot. Connections are clean and solid, but the car hasn't run in ten years, so who knows the condition of the alternator.

Could the hot terminal be a sign of the battery doing too much work?

And can I do the old school test of disconnecting the battery once the car is running to see if it will run off the alternator? I know it's frowned upon for newer cars with computer systems, but it should be okay for an '81 right?
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1981 924 N/A 5-speed

[ideola]

DO NOT DISCONNECT BATTERY WITH CAR RUNNING! This will wipe out the voltage regulator.

Proper test is to check voltage at the battery with the alternator running.

Heat in wiring is usually due to resistance. I would be highly suspicious of the main battery-to-starter-to-alternator harness. They are particular susceptible to heat fatigue on the NA models due to the proximity of aforementioned wiring loom to the exhaust manifold. I suspect that you may have a lot of resistance in that loom which is causing the terminal / wire to heat up. Best to carefully investigate before running the car for long periods. You don't want an exploding battery or under-hood fire. I would also recommend removing the old harness and then buying all new components with larger sized UL-rated wiring and rebuild the whole thing, then put it in a heat resistant shield like firebraid.
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erstwhile owner of just about every 924 variant ever made

[Johnny_Haywire]

Thanks for getting back to me on that, Dan.

I will check the voltage at the battery with the alternator running tonight. It's definitely not safe for driving right now.

Any pointers on where I could get the proper cables/wiring to do this? I'm so close to having her on the road...
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1981 924 N/A 5-speed

[Rasta Monsta]

I realize Chicago is just a little village, but there should be an automotive wiring shop near you that could either copy the alternator and starter harness for you, or sell you the appropriate wiring.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Johnny_Haywire]

I'll hunt around and see what I can find, but a quick google search of automotive wiring shops yields nada. Perhaps an automotive audio shop...

On the off chance that the alt is bad, could that be a cause for the hot terminal?
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1981 924 N/A 5-speed

[fiat22turbo]

I rebuilt mine using generic parts store cables. One from the battery to the stud on the starter solenoid. Then one with two lugs from the solenoid to the alternator.

Take the old wiring one out and measure the lengths.

You should probably do the negative side at the same time. Pay attention to the braided grounds for the coil and alternator.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[ideola]

I'm guessing a place like this would have everything you would need:
https://cityelectricsupply.com/branchlocator.aspx

I still haven't found local equivalents to all the suppliers I used back in MI!
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erstwhile owner of just about every 924 variant ever made

[Johnny_Haywire]

Thanks for all the helpful info, guys. I seriously love this forum.

I was at a local Irish-named chain auto parts store picking up some things today and noticed they had a pretty wide assortment of different cables, so I will probably go that route unless what they have just won't work.

I forgot that I already have a new negative battery cable. It was in the Rockauto box. I'll pop that on tonight to get started and will also test battery voltage with the alternator running.

I'll definitely post an update later with my findings.
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1981 924 N/A 5-speed

[Johnny_Haywire]

Had a little time to mess with the car tonight.

Here are the results from the battery voltage test:

Off: 12.68V

Running at idle: 14.6-15.5V

Running at idle with wipers and headlights on: 13.2-13.7V

Same conditions as above but while revving engine: ~15-17V

Alternator seems okay, right?

I installed the new negative cable and will do the same tests next time I run it.
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1981 924 N/A 5-speed

[Rasta Monsta]

I would say its overcharging. Throw a new regulator at it. . .ten bucks.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Johnny_Haywire]

Thanks, Rasta!

Do you think that's the cause behind the positive terminal getting hot?
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1981 924 N/A 5-speed

[Rasta Monsta]

Maybe. 17v heap too much.


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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[musicalannette]

the max you regulator really wants to be at revving the engine 14.5v

i would think you have a zenner in the regulator circuit thats on its way out.

i would still check the loom out tho.

one night you will be driving along in the middle of nowwhere........ the alternator will start to struggle to charge and feel like you are trying to jump start another car, then the light comes,followed by a ton of smoke from under the bonnet as the wires all melt together followed by the fan belt letting go as the alternator blows itself up trying to charge a short circuit. if your lucky it wont be raining at it will be the middle of summer on a moonlight clear night, you will only be 3 miles from home and you can fix it. then again, it might be raining and 50 miles to the next garage and and porsche alternators are sooo cheap..........

you really want to be using p.t.f.e. insulated wire as a replacement. thats the same stuff the heat shield cover is made of, in fact you can get sheets of it to use instead of aluminum foil in your cooker too, and its reusable, handy stuff and less mess the baco-foil.

http://www.agacookshop.co.uk/bakeoglide-cooking-liner.html


like i say, when my alternator blew i was lucky, but as a friend once said, better to be lucky than good....
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

[Johnny_Haywire]

Still chuckling here, Musicalannette

With the heat coming through the positive terminal right now, I don't even want to drive this thing to the pub at the end of the block.

I ordered a voltage regulator today, which will be in tomorrow at noon, so hopefully I'll have that on tomorrow to test the outcome, but I also have the brakes apart on the port side of the car, so...it may be a few days, but hopefully not. I only have one half of the garage, so I have to plan out which side of the car I'm working on and position accordingly.

Man, the brake calipers are something else on this one. Granted, she sat for 10 years before I got her, but the "sliding" part of the caliper is not sliding currently. I was able to lube it up and massage with a hammer once my thick head was able to figure out how they worked, but was not able to finish it tonight. I did get both pads out, so that's a start.

And, best of all, I cleaned the brake bleeder with a wire brush, soaked liberally with penetrating oil and, after leaving it a while... she loosened. A Christmas miracle...

Baby steps, I guess. I thought I'd have this car on the road by mid-August. Now I'll be thrilled if it happens by mid-September. Steady as she goes... a little bit each night.

Thanks again for all the knowledge, gents. I will keep you posted once I get that regulator in.
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1981 924 N/A 5-speed

[Johnny_Haywire]

I pulled the alternator today. Not too bad of a job, especially after ignoring the Haynes manual and reading a great how-to on this board, though the nut for the larger of the two wires coming into it was not easy to get off. A bit rusty...

That said, the wiring itself didn't look too bad, the rubber shielding around them was still supple, though I'll still replace the wires for a fresh start.

My voltage regulator did not come in today, unfortunately, but when I pulled the old reg, one of the spring loaded contacts had a noticeable problem.



It held together when I took it out, but when I picked it up, the end of the contact just fell off. Probably another result of the car having sat for around 10 years.

Once again, I send my sincere thanks for helping me figure this out.

I'll be sure to post some test results once I get the new regulator in there. Hopefully tomorrow night.

Cheers!
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1981 924 N/A 5-speed