My car is an '85 12a stockport with an MSD direct fire ignition.

I've done a pretty thorough test on some NGK R5672A-8/10 plugs as per Paul Yaw and the tutorial on Mazspeed.com, and I can say that under no combination of heat range (both and 8 and 10 were tried) and gapping (from .85 to .65 to .45) did they perform anything but poorly. I noticed a very distinct loss of power in the midrange, and probably a total average loss of 20% power or more compared to stock Autolites. To sum it up, they suck.

Though, I have to admit I was wrong about the stock first gen NGK plugs. Fresh NGK plugs are much better than fresh Autolites, even with the MSD. Plug life may still be an issue, however. Maybe I will try second gen plugs next.

 

I never bothered to try side fire plugs. I never saw a need for them.

I bet you'll like the 2nd gen plugs in leading since you've got direct fire.

 

Yeah, the R5672As are "V Power" plugs. I don't see why that would be good for side fire at all. But that's what they said to use...

I will try the second gen plugs when I get the chance. I'm happy with the car as it is with the regular NGKs in it. Do they make "platinum" plugs for the FC? I'll just have to ask the folks in the 2nd gen forum what they use. (Or do a search, heh).

I'm not going to screw with it now. I was just driving around back home and I saw a black "S" model SA with some grass growing under it (I'm always looking) and I asked the lady with 50 cats who owned it and she said "I don't drive 'my baby' in the summer because the window won't roll down." 69k miles on a Mazda rebuilt motor, with a brand new '79 gauge cluster installed at the same time [?], brand new oil cooler and all hoses in the front, etc. [ka ching!] Nothing bad but a little surface rust and a few really easy dings... only the hood was a goner.

She wasn't sure if her husband wanted her to sell it with all the money in it but she said she'd be happy to take $500. I told her that if her husband won't let go for it, I'd be happy to fix the window for her anyway

 

And another example of how nice 1st geners are....!

On the other hand, if that car had been a Honda, I bet you wouldn't have offered to fix the windsows.

 

I had problems with the Yaw-recommended plugs. Also the Yaw-recommended timing settings... but he does all of his tuning on 93 so that probably makes a difference.

If you want side-fire generiplugs, I'll speak up again on the benefits of the Autolite 3923's. They wear a long time (over 20k on one set of plugs!), they don't seem to foul (the MSD may be helping here), and they're about a buck a piece. Oh and they have a 5/8" hex so they'll work in any rotor housing without a special thinwall socket.

 

A Honda? 'ell naw. All it needed was a window channel and I have some spares.

She said she was worried that I wanted the car for the parts... I told her that I wanted it to put the perfectly good parts I keep pulling from my car onto.

 

Yea I had no luck with homemade side fire plugs either. Whether Direct fire, stock or MSD, never got anything positive out of it. I have run Autolites for a while now on the streetcar and they're not bad. But NGK's are still the best in my book.

 

3923 huh? I'll get my buddy at AutoZone to grab me a set if they stock them. $.80 each

I'll have to wait until the weekend to try them though. I don't have a vice or any [real] tools at my apartment and doing side fire plugs with a file is kinda tedious.

 

Try Discount/ Advance auto. Thats what they stock for a first gen.

 

I don't even use a vise - Dremel wheel to cut just the right amount off, tap it down with a hammer, all while the plug is held in my hand.

 

I've tried the Autolite FB plugs... they're... 2523... I think. Okay but not as good as *fresh* NGK stock plugs. Curiously the idle is better with Autolites but the power and responsiveness are better with stock NGK plugs.

I'd been using Autolites for a while because I initially thought they felt better, but I didn't have the MSD installed right so neither felt too great before I figured it out and I never went back to the stock NGKs until now.

3923 probably has to be cut -- right peejay?

 

Yes they need to be cut. They were stock equipment in some Ford Contour ('95? It was a Zetec powered model and they are non platinum). I had a set of nearly new take-outs from a customer's car, and I said hmm, correct reach, 5/8 hex, and free. I'll cut 'em down and try them, and go from there as far as heat range is concerned.

Heat range seems to be perfect, for street/drag racing anyway. Sometimes things work out like that.

I'll try them in my next engine, without MSD. I sold my MSD, and the engine in the car now has plugs that will *not* come out and I will *not* force them, so it's going to have the same plugs in it until the engine gets torn down.