'79 911, new plug wires, what's up with this distributer?

[sporqster]

So long story short, we've had this '79 SC for about a year, and it has developed a bit of a valve tap. So I hop over to my favorite tech forum and read 'valve adjustment made easy'.... seems like something someone of average intelligence and a set of tools ought to be able to handle, so I jack her up, drain the oil, remove all the junk in the way off the top of the motor, pull out 4 spark plug wires but on the 5th...

DOH!

Well, the car is out of commission until I get this fixed, and she's a daily driver, which means I've got to do carpool until I replace the spark plug wires. Semi-locally available are these cheapies: http://www.partsamerica.com/ProductDetail.aspx?mfrcode=XCT&mfrpartnumber=6093&parttype=5004&ptset=A

Then one of my wealthier Porsche purist buddies (whose opinion I generally respect) tells me I definately need the OEM style braided wires, that cost about twice the price or more. Else the air box is liable to explode!

Fact or crap?

Second question, perhaps should be in a seperate post but... look at this distributer:

Is this the right part here? I've been told this is supposed to be electronic ignition with a vacuum retard and advance.... only has one vac line to it... and looks pretty mechanical to me.

PS I know almost nothing about Porsche's - but the wife bought this one as her daily driver, and while I don't get to drive it much it stays in the garage and therefore is my responsibility to keep running. Your help is much appreciated!

[snbush67]

It is the right part, IE ditributor and rotor, no you dont need the factory braided wires but they are normally better than the aftermarkets ones as they have the Beru connectors. When you remove the wires you should do it with a slow rocking motion while you pull.

Check your airbox to see if it has been upgraded with a pop off valve, if it has not then do that mod immediatly.

[74cookiecutter]

"do it with a slow rocking motion while you pull." Nice ...


Saw some ignition wires on Ebay this weekend, for a good price.

[Walter_Middie]

Sporqster,

snbush67 is correct, but I'm going to expand on what he said a little. If you had mechanical ignition, you would see a set of breaker points under the rotor. What you see is all electronic.

If you do a search on plug wires, you will see a wide range of ideas on what works best. Porsche added the braided ground sheath on the wires to try and avoid air box back-fires, but that has been shown to not work. Most aftermarket wires do not have (or need) the braiding.

Looks like your air pump has been removed - that's good, as long as you don't need to pass emissions.

P.S. Don't remove the spark plugs prior to doing a valve adjustment as some carbon may drop into an open valve and cause faulty readings.

[sporqster]

Originally posted by snbush67
Check your airbox to see if it has been upgraded with a pop off valve, if it has not then do that mod immediatly.

Got it. I think this must have been the last upgrade made by the previous owner, as it is still shiney black plastic - looks pretty new.

I guess I just misunderstood what an "electronic" distributer is. I figured 'electronic' distributer was something akin to what you'd find on a modern car- an optical or magnetic pickup feeding an external gizmo (i.e. ignition computer) that does the sparking.... Much to learn have I in the ways of the Porsche.