Sparkplug help

[maxford]

95 Ranger, 2.3L, 5spd.

I have new set of 8 motorcraft plugs on the shelf from a previous project that I did not use. They are AGSF-32PM.
According to O'Reilly auto parts the Ranger calls for AGSF-32FM.

Both are platinum, 5/8inch hex, 14mm thread size, and have a tapered seat. It has been a long time, but wasn't the "32" the heat range? if so, they are both the same on that.

I don't know what the suffix difference does to the plugs between "PM" and "FM." Anyone know or have an opinion If I can use these? I know it will be a pain to do this job and can't afford the time to do it twice, but cash is also at a premium right now for me and I'd like to save a few pennies if I can.

thanks,
Greg

 

[Mark_88]

Apparently they are the similar but you might want to read the comments by Abe on the link below...

http://www.lincolnsonline.com/forum/archive/index.php/t-76422.html

The FM have a fine wire single platinum tip and tend to be more maintenance intensive (need changing more frequently)...and he suggests to return them for the proper ones or the newer N standard...

I experimented quite a bit with plugs in my 4 banger 4 plug and actually found the Bosch Platinum 4 were the best for a carbureted setup...fuel injection and coil packs are much more effective so the stock plug is OK...

meaning you can use these FM plugs but expect to change them before 50,000 miles...the only other thing you need to check is the plug length and the depth of the electrode...

Between the older heads there was a considerable difference in how deep the plugs needed to be for effective spark. I'm not as familiar with the newer plugs but a simple test of holding them up side by side and checking them visually...if the threaded part is the EXACT same length then it won't affect the plug firing...if the FM is shorter than the PM...do not use it...or if it is longer...it can actually get tapped by the piston and bend the end of the plug...essentially eliminating the gap...and won't fire properly.

 

[tomw]

Read here:
http://forums.corral.net/forums/gt-sohc/666984-agsf-32fm-same-agsf-32pm-spark-plugs.html

Consensus at that site is they are good interchange or substitute.

I expect they would be mechanically the same, but with a different center electrode. The heat range and 'reach' should be the same.
tom

 

[maxford]

Thank you!