Got my new plugs in despite the snowy weather. They are Autolite Racing AR-472. The straps are VERY short and doesn't even come over the top of the electrode. Do I gap measuring from the corner of the electrode to the strap, or still hold the gapper flat across the dop of the electrode?
I am guessing just to gap between the top corner of the electrod and the strap. As opposed to holding the gapper flat across the top of the electrode. That would make a gap larger than what I am trying to obtain. Dave, thanks for the instructions, but they are the same instructions used for any other plug. I am running an MSD and use .060 gap. these are nowhere near there.
I dont understand how a company can put less on a part, give it a fancy name, and double or triple the price...lol and the threads are different I think..really looks like it...have you test-fitted them yet?
They are gapped at .023 out of the box. That picture is deceiving. It was taken in "macro" mode on my camera, and the lens is only 4 or 5 inches away from the closer plug, making it look larger than the one behind it. They are the same size in real life. Actually, after looking at that picture again, they REALLY look like way different sizes. But they arent.
A quote from autolite.com "* The proper gap for Autolite® Racing Plugs is set during the manufacturing process. Do not gap before installing." ...bottom of page two, http://www.autolite.com/pdf/Autolite_HP_Apps.pdf
DAMN!!! I guess I will have to make a call to Autolite AND MSD and ask for their suggestions. I just cannot justify running a crapload of plugs on an MSD/Pertronix system with only .023 gap. That just AINT right. I will let you all know what the "experts" tell me...after I call them.
Side gap plugs have been around since before the 1960's. The gap is supposed to be very small so the turbulence in the chamber won't "blow out" the spark. They are used in high compression and blown engines where the small gap is absolutely necessary. In a stock engine with lower compression you may need to widen the gap slightly to .028" or .030". The plug is designed to fire to and from the sharp edges of the electrodes to reduce the amount of voltage necessary to fire the plugs under extreme conditions. They are called "racing plugs" for a reason.
What made you decide on that plug? I asked 2 friends what plug to run in mine. One owns a high performance shop and the other owns a speed shop. I'm running AR 3910's. The chart says it's for chevy and hemi's. But I run Edelbrock heads. The differences in our plugs are that mine has a .750 reach where yours is a .708, Yours is a tapered plug and mine is a gasket plug. If you don't come up with an answer PM me and I can ask them what they think would be the best plug to use. P.S. Edelbrock told me what plug to use and they burnt really lean. These guys told me they would be good for a street plug but not for all the MSD stuff I run.
I found these plugs by looking for both motorcraft and autolite in the stores and I never got a straight answer on which plug number to run, and then I could not figure out how to get a step or two colder. So I got on jegs and found the autolite plugs, identified the reach, thread, etc, and found that the AR474 is the stock replacement for my heads, then lowered the number 2 steps for the AR472, then ordered those from my O'Reilly. I didn't buy them for the short strap, and didn't even know it had them until I opened the box. I just bought them for the brand name, size, and heat range. Yes, you posted a link, and step 2 was "gap the plugs"...
Since you are correct on the gap, Im assuming you measured them. Just widen the gap as on a normal plug, I use a pair of big side cutter wire cutters to widen mine, As you cant pry on anything else. I run the 3932s and gap them at 35 thousands.
