Stumbling above 4k - '82 SC

[larkja]

I did a search and found a similar thread on a 3.2 Carrera but since the electronics are different, I thought I would try a post.

I have a stock 1982, 911 SC. I was just at the track (Thunderhill) and here's what happened:

First two runs were awesome. Halfway through the third run, I started getting some stumbling above 4k RPM. The more I drove, the worse it got until it wouldn't even go past 5k RPM. So I drove her in, parked and pondered about the fairness of it all - my first track day this year and... I thought this was very odd since it was running great just prior. The car wasn't overheating, oil level was fine, I just topped off with 91 octane gas. I was able to drive her home, just kept it below 4k RPM.

The entire engine was rebuilt 20k miles ago, from valves to piston rings. It sounds like some sort of fuel delivery (bad fuel filter, injectors, bad gas?) or spark problem (plugs?) but before I go ahead and start tearing into things, I thought I would see if anyone here had a similar problem and what they did to fix it.

Thanks
Jim

[avendlerdp]

I'll bet ignition. Check the usual cap/rotor/wires/coil stuff first.

Alex

[al lkosmal]

I had the same symptoms. A new coil was the answer.

[larkja]

It's a brand new distributor 20k miles ago. I'll check the coil first and go from there.

Thanks
Jim

[stlrj]

How old are your ignition cables?

[larkja]

I just took a look at the coil and I bet it wasn't replaced with the rebuild. I went through the receipts and did not see anything relating to a coil. I have receipts for distributor, new plug wires, cap, rotor, etc.

Would you recommend replacing the coil wires as well?

Also, I was checking out prices on coils. The factory Bosch unit is almost $180 - wow. Have any of you used a Jacobs or MDS coil? Any compatability problems with the rest of the '82s ignition components?

Thanks

[larkja]

Sorry, I meant ignition cables not coil wires re. your question re. replacement.

[stlrj]

I had the same miss above 5K that was caused by old, corroded ignition cable terminals on the cap and the coil.

[larkja]

I just started into the project and as soon as I started to disconnect the leads to the coil, the wires on the negative side just fell off - looks like I had a faulty connection.

So I removed all the black tape and inspected all of the wires in the engine bay. Some needed a little repair and connectors. I put it all back together, re-connected the battery, and voila, all is well.

Thanks for all your input and pointing me in the direction of the coil - that did it.

Jim