What sparkplug to use?
 

What spark plug to use?
My setup is 2.7L (150HP) engine fitted with webers and 2.7S CIS cams, I also have Dansk sport muffler (2 in 1 out) and the pre -74 exhaust headers.

I use the 1968-1971 Porsche 911 Spark Plug - NGK - Standard Part number: NG2411 Pelican Parts sell the Bosch WR5DP Platinum, great plugs

good luck.

Bill

I just pulled the plugs out of my car and found that the PO was running plugs one number colder than recommended - NGK B8ES, rather than the suggested BP7ES. The engine is a '75 S. There does not seem to be any unusual fouling. What does this tell me?

Jerome,
I ran B8ES in my motorcycles when I raced motocross. It is a good plug. The heat ranges for NGK don't change much with one number difference.

To answer your question, the PO put in the wrong plugs. Use what Porsche recommends and you will be a happy camper.

Mark

Use the coldest plug you can without fouling. Colder means more protection against detonation/preignition.

if mine I'd start with a hot plug, NGK BPR5ES, and lean idle screws until it doesn't foul. You may have to run webers on the rich side for driving issues though.

in a better world you'd slowly start leaning until you could run BPR6ES clean

then lean so you can run BPR7ES clean for an ideal world

Weber driving issues may determine how lean you can go

an ignition curve set for carbs helps. If original CIS dizzy disconnect vacuum canister and perminately plug it. Set total abvance to 35 deg

done

thx for the catch