2.0 911S plug fouling problem

[911pcars]

I'm sensing too many related but separate threads and little obvious indication of what responses fit whose question.

Sorry.

[911ts3]

Hi, yes, ganun's reply is to a 2004 posting, my fault probably by reviving an old thread after searching for answers to my plug gap question.
Apologies, will have more info later this week after I've fitted new cap, rotor arm, and tested the new BP7ES's out at various gaps.
Many thanks
Steve
911ts3

[surfdwn]

I had a '68 2.0 liter that the PO had taken up to "S" specs, like this car. The car would not run a week without the plugs fouling.

I switched to the Crane ignition, which helped but did not completely solve it. I finally switched to the expensive, original plugs ( I don't remember the number since it was 10 years ago) and the problem went away.

The ignition upgrade was the most bang for the buck.


David Nolen
1970 911T

[HawgRyder]

My solution for a plug fouling engine (not a Porsche) was to go to a different type of plug (barrier gap).
Bosche make a plug that has no side electrodes....just the metal threaded part...and a small center electrode sticking up.
The idea being that the spark will jump to the side where the resistance is least (it changes form spark to spark I think).
The gap cannot be adjusted...but they seem to work like a charm...and in the case of a rotary engine...the is nothing to break off and score the chamber if the plug fails.
They have an extremely large heat range...are good for idling and high speed runs...and come in many lengths (thread depth).
Just my $.02
Bob

[911ts3]

Hi Bob, sounds good, do you have a link to the Bosch sales bumf ?

Steve
911ts3

[merbesfield]

How about a plug suggestion for a normal 66 2.0. Don't know what's inside engine as car is new to me.

[blau911]

I just saw that someone revived this thread which I started back in 2004. I flipped thru the posts and realized that I never ended up updating the post with what the eventual problem was and how it was sorted out. I bought an MSD 6AL with a blaster coil. It took appr 1 hour to wire I swapped out the plugs for the NGK BP7ES and adjusted the gaps. The problem was solved immediately, and never had a plug fouling problem again. The motor idled perfectly and had amazing acceleration all the way thru 7400 revs....
Anyone with a built 2.0 S or higher compression motor should seriously consider installing an MSD.

[911pcars]

Yep. A higher capacity ignition system is the preferred solution to minimize low speed plug fouling, especially on early carbureted and MFI engines. If there's an over-rich condition on a later CIS or EFI engine, diagnose and repair the fuel induction system.

Changing the spark plug heat range is usually a last-ditch panacea for oil-fouled plugs. There's only a narrow heat range selection for a particular engine. There's a higher risk of engine damage using hotter-than normal plugs to mitigate an over-rich fuel setting.

Sherwood