well i need help understanding the Autocrafters spark plug numbering system the spark plug number i have is BSF42C i want to go i heat range hotter ...what number should that be?
Is it Autocrafter Or Motorcraft? I have an NGK book that lists a BSF-42 Motorcraft that corresponds to a NGK WR5. The hotter plug for that is a WR4-1. that references back to a Motorcraft BSF 44C. Not sure if that's a help or not. Hope so.
to scooper, with the stock plugs they are carbon fouled really bad.. that was with the untuned carb(now its leaner) but i would still think that there will be some fouling and a hotter plug will "help" to don. its Motorcraft......i was searching and found that one step colder was BSF32C so i presumed that BSF52C was hotter. thanks for the input
Bowstick be sure about the heat range. if you get it to hot and do a lot of high speed running you could have some bad motor problems. example such as hole in piston.
BF42's are Autolite's. The hotter plug will be a 52 number. There will be an increased chance for detonation with the hotter plug. 42's should be plenty, that's what I run.
be sure that you are not trying to "read" those plugs while you are just idling in the driveway... All plugs will be dark when idling. The only time "reading" plugs works is immediately after a wide open throttle run. When I read mine, I take it on the highway, where there is no traffic (you know where i live out in the boonies). I usually leave it in 2nd gear so I am doing 60mph at 4500 rpm, then immediately pull over onto the shoulder and stop as fast as I can and cut the motor. Then they are usually all white to very light tan colored (on my old motor). Some guys even cut the motor while they are moving, but I don't want to risk hitting the key too far back and locking my steering wheel up.
oh...ok didnt know that.. thanks guys that might change some stuff.. because 90 percent was at idle thanks pat
