Plug wires... Maintenance replacement item, or fix when broke?

adamnitti · adamnitti's Garage

My '85 still has the original plug wires. Do they 'start' to go bad?

rfix'n · 12-19-2001, 08:48 AM

They can be tested for end to end resistance. Do a search for more specifics. Providing they meet this criteria and there is no arching (check with engine running at night) then they are okay.

KTL · 12-19-2001, 09:31 AM

Adam,

The Porsche wires on your car can be "broken down" into separate pieces if you need to test/replace them. The connectors for the dist. cap and spark plug ends unscrew from the wire itself. You can test all the components individually to see what's bad.

Warren, John Walker, Superman, et. al. posted about this subject awhile back. There's some good info. in there about terminal part #'s, what wire to use, what the resistance values for the connectors and wire should be, etc.

Search away....

BER · BER's Garage

Adam,

I replaced the plug wires on my '84 911 a couple of years ago. I used new Magnacor 8.5MM wires with Beru connectors. I believe the old wires were the originals (had about 75k miles on them). I did not think I needed new wires...until I replaced them.

Boy, what a difference the new wires made!

If your wires are original, I would suggest replacing them because they are 16 years old and probably breaking down.

Regards, Bruce

dickster · 12-19-2001, 11:56 PM

bruce

i just ordered some Magnacor 8.5MM wires for my 1986 coupe (still original wires i think), but they won't arrive now til after xmas! bugger!

i'm curious, what difference did you feel that i can look forward to?

thanks

richard

ChrisL · 12-23-2001, 08:07 AM

I just replaced the plug wires, spark plugs, distributor cap and rotor as part of the 90k maintenance on my 1986 Carrera. I also replaced the DME relay at the same time (it was original, the date stamped on it was from 1985). The wires were also original - outwardly they appeared fine, although the rubber tubing that they ride in over the cooling fan was cracking. I got a new set from Pelican. The new wires have the exact same connectors on them (Beru) as the originals. The major difference is that they don't have sections covered in the aforementioned tubing like the originals, and you'll have to use the two- and three-wire standoffs from your old set. It takes some effort to route the new wires and get everything reconnected. I removed my a/c compressor (just set it on top of the fan) to route the wires under the compressor bracket.

The difference was impressive. The engine seems much smoother and clutch judder on takeoff is significantly reduced. I allowed myself the double placebo of new wires and new DME relay at the same time, so I'm not really sure if there's not some effect of spending $350+ and wanting to feel some difference...

Chris.

KTL · 12-23-2001, 10:29 AM

Chris,

You have to unscrew the connector (dist. cap end is probably closest) on the old wires, remove the rubber sleeve and put it on the new wires.

ChrisL · 12-23-2001, 11:53 AM

Kevin,

The new wires came complete with new rubber boots and new ends. I did unscrew the ends in some instances to get the outer rubber hose on them. If you're referring to the need to remove the a/c compressor, you're correct that I could have probably gotten away with leaving it in place.

Chris.