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Gapping Autolite AR-94's?

5K views 9 replies 3 participants last post by  V8ThunderCat 
#1 · (Edited)
I recently bought one of Jerry's old Diabo chips and it required that I installed a 180 degree t-stat and 2-step colder spark plugs. After searching through these forums I decided to get some AR-94's because of the cut back electrode. I was installing them and when I got to the 7th plug I realized I may have made a mistake. I never checked the gap of the plugs.

Thinking that these plugs should be gapped like any other plug I attempted to gap them @ 0.054. I had to use some vise grips and it took a lot of trial and error and I think I got it right. The sides of the electrode is now all gouged up. I also cannot tell if I'm using the gap gauge correctly because of the way the plug is made. For now I'm leaving that one plug the way it is and resuming this tomorrow when I have daylight.

If someone has used these can you please let me know where the gap is supposed to be! I'm also trying to find the correct tool for gapping the plugs but so far I cannot find them locally.
 
#2 ·
I used one of those round-ramped tools that are 99 cents at any parts store counter.
 
#3 · (Edited)
That is what I've been using. The AR-94's start off with the gap around .030. When I began trying to use the gauge to widen the gap the gauge became a bit bent. Last time I gapped plugs with the gauge a little of the ceramic was broken off on one of the plugs. Luckily that didn't affect the plug's performance. I know that there is a tool designed for gapping plugs but so far nobody at Autozone or Advance has any idea what I'm talking about.

I guess if the gauge reads .060, (even at an angle), I'll go with it and hope it doesn't miss. If it misses at least I'll know to lessen the gap but I really hope I don't have to take the plugs out and regap them over and over.
 
#4 ·
You want a wire type gauge, not the flat style. It's a piece of steel wire, different sizes, bent in a box pattern...

Like this, but this one isn't big enough diameter wire:
http://www.amazon.com/Tools-2327-Spark-Plug-Gauge/dp/B000CO9NUW/ref=pd_bxgy_auto_img_b

The gap needs to be even all the way across; angled will wear the closest side more.

I bought my gauge at a cycle shop, long ago. it has a tool with notches in it that hooks the bent electrode and bends it precisely.

File off any rough spots; those can make 'hot spots" and cause detonation.
 
#5 ·
I also have ar-94s. Though I used the 99 cent tool, I agree with Grog6 that the wire tool is better.
 
#6 ·
Yeah, that's the tool I saw somewhere but I haven't seen it since I moved to NC. I really need this done tomorrow because this is my daily driver and I'm not going to be able to borrow my girlfriend's car again to find it. I'll order it so that I'll have it for the next time. I probably should have been changing my plugs more often anyway. I'm now hoping that maybe my low idle and stalling has been caused by worn out plugs.

I'll do what I can with a file to get rid of the rough spots on the first plug. Hopefully I'll do better with the rest. I think I was able to keep the electrode in the proper shape while I was bending it. I held the electode on the sides close to the base with a vise grip so that the overall shape wouldn't change. I'll double check the first one and maybe bend the tip of the electode if it does appear uneven. It's just with the way that the electrode is cut back the guage can slide in at an angle and I'm not sure if that affects the reading. I guess it doesn't seeing as how a gap is a gap no matter what angle it's measured at.

Nobody has mentioned anything about the gap so I'm going to assume that .054-.060 is fine.
 
#7 ·
Oh sure, now everybody carries the gapping tool after I drive out of my way to pick one up at PepBoys.:rolleyes: It was about a year ago when I couldn't find one at Autozone or Advance. Well, at least I like the one I got better than the ones they carry that may have a wider range of guage wires but have fewer adjusters. The one I got is just like the one shown in that link to Amazon.com.

I used it on the last plug that I haven't installed yet. It worked like a charm even though I may have widened it .001 too much. Close enough.

I talked to the Advance where I paid for the plugs, (although I had to pick them up at a different Advance and they only carried 8 total), to see about ordering one more to replace the one I messed up. The guys at this Advance are really cool even though they never have what I need in stock. He offered to trade the plug out with a new one after some arrive from another store in the morning.:D Unfortunately I'm in no hurry to finish this now that the weather is going to be cold and wet for the next few days.:(
 
#8 ·
Unless you have a blower or run nitrous a lot, the gap really isn't that critical. (on our cars)

I set at stock, which is .054 in my book.

Wider=more voltage, narrower = more current, pretty much. More voltage wears wires, more current wears plugs.

These coils can do ridiculous voltage with good wires; I use one to feed a tesla coil for megavolts. :D

You aren't having fun if you're not scaring the neighbors, lol. :)
 
#9 ·
I would love to play with some tesla coils!:D

I figured I would go with .060 because the new gauge is much easier to use and that's the closest wire it has to .054. I'm also not 100% sure when I use the "coin" whether to center the electrode on .054 or align it on the right side. I also read that + or - .007 doesn't make much of a difference but I could have read that wrong.
 
#10 · (Edited)
Alright, I seem to be finished now! So far the chip and new plugs seem to be working great. I cannot believe how my car feels now! I still need to either replace the 87 octane with 93 or pull the octane pin. The car doesn't seem to stall anymore so now I can concentrate on my other problems!:D

EDIT: Surprisingly my TC shudder has been diminshed by at least 85%!!!
 
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