A previous owner put in NGK WR 5 plugs. Not a common choise obviously. Finally I pulled them as the car was missing on idle some times. Found some oily residue around the threads, although the insulators & electodes were not obviously fouled. Car isn't driven a lot & seldom sees the highway. A couple of manuals & parts books refer to Autolite BF 82s for the Y. Is the Motorcraft BSF 82 C similar & likely to be satisfactory? Thanks


Paul

Paul! I have found the same thing as have others.Champion plugs.Not from an oil leak.Anyone know where it comes from?

  

Mark: Yes, I thought it was odd that the perimeter of the plugs would be some what oily. Too cold a plug maybe? And one plug looked like it might be leaking where it contacted the head. Maybe there was dirt on the contact surface? Anyway, still hoping to get advice on whether or not Motorcraft BFS-82C plugs might be satisfactory? I happen to have those on hand.

Paul

BSF82C is just an BF82 W/radio suppression and copper core.

The oil is probably a v/c leak.

Regards,

Ron.

I got this explanation on another website.

While it may look like dirty oil, it isn't, this is unburnt fuel that all the lighter elements in the fuel have boiled off leaving the heavier hydrocarbon components behind. This is not unusual to find even on race engines. I wouldn't have known this myself if I hadn't run acrossed the explanation from a very respected pro engine builder on another site. This "fuel" is here because the seal(tapered seat or gasket) is above the threads but the threads themselves are shielded from the actual combustion process. Almost sounds crazy but it is true.

I have been using NGK WR5's for about 5 years in 2 motors a stock 272 and mild built 292.  They work good.  I am a motorcycle technician (Japanese) so Champions are garbage to me and NGK is good stuff.

Nat: That's an interesting explanation. The engine in my car had been in chassis a long time & is somewhat tired (how much may be revealed in a compression test I'm going to do shortly) & I thought that also might be the problem. The NGKs used in the engine have been in there quite some time, also. Thanks to everybody that replied..

Paul