[Mark]

My 82 SC stopped running twice in last few years and had to be towed to two different shops, where the coils were replaced but nothing was found that could have caused the failures.
Could it be that the coils are just failure-prone? Anybody else having this problem?
I'm going to keep a spare in the car to avoid future towing costs and calls to wife to come get me ... again.

[Jase007]

COP (coil on plug) are more prone to failure but lucky you, you don't have that ignition setup. My original Bosch COPs for my BMW lasted 170k miles... not to shabby.

Could it be that the coils are just failure-prone?

Just the opposite. I've had to replace 1 in 15 years (~140k miles) on my '76 911 (same as your SC, one coil). And the old one wasn't that for out of spec, rather part of preventative maintenance.

CD Box is "more likely" to fail sooner than the coil. Can you hear your CD box "whine" when the engine is running?

[Trak Ratt]

Mines still going stong on the SC after 15 years, ~200K miles. Lots of track time too No indication in docs from PO that it had been changed since new in '82. I'd be looking at the system for other issues.

[Cliff Claven]

mine too. and coil is not something you hear about as being a problem on these cars.

did your coils give any warning of a problem before the non-starts and failed coil diagnoses?

[Chopper Dropper]

Originally Posted by Cliff Claven

mine too. and coil is not something you hear about as being a problem on these cars.

did your coils give any warning of a problem before the non-starts and failed coil diagnoses?

DME??
Dirk

[type954]

Originally Posted by Chopper Dropper

DME??

No DME on a CIS/K-Jet SC...

[Vicegrip]

Check voltage reg, correct plug wires and pug type and coil mounting. Heat and vibration can be a killer.

[cmartin]

That's great advice. You shouldnt need a spare coil, they rarely are a problem. However, it might not be a bad idea until you find the root cause.

[matt de maria]

Bosch coils for the last ten years have been made in Spain. They have been very problematic. Even dead out of the box. Particularly Sc-Carrera coils and the COP for the watercooled. Sometimes one problem is solved with the introduction of another.

[Mark]

The CD box does whine, and there was no warning before the coil failed; in fact, I was thinking how good the car was running just before it flamed out.
From what Matt says, it sounds like there might be a bit of luck involved in whether or not you get a good coil or not. The comments about looking elsewhere for a contributing problem make a lot of sense.
Thanks, guys.