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Old 01/09/12, 10:15 AM   #1
f2502011
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Hotter Spark Plug than an Autolite AP26?

Currently have the recommended stock Autolite Platinum AP26 in a 302. I would like to try and run a set of hotter plugs but cannot find any info online that tells me what is a hotter plug that will work. Anyone have any info on this?
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Old 01/09/12, 10:44 AM   #2
broncnaz
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26 is as hot as they sell in that size range. Are you sure that the 26 is what is recommended as stock? usually its 25 or 24's that are stock. I probably wouldnt bother with platinum plugs if the engine is carberated. just a waste of $$. You need to be very careful about running hot plugs as you can do more damage to the engine with hot plugs than cold plugs.
Here's the only chart that I could find I used to have one somewhere but couldnt find it. Your plugs in the upper right hand corner. http://www.cvproducts.com/upfiles/Autolite.pdf

73 Ranger 2 1/2 lift 302 TFS heads NP435,PS,PDB, tierod over, 33x10.50x15 BFG M/T
71 Sport 63,000 miles all orginal except for cut fenders 302 3sp 4.11's D44/BBTrac lok rear
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Old 01/09/12, 11:37 AM   #3
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As much as I hate msd stuff..a Carb setup benefits greatly from their boxes.

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Old 01/09/12, 12:32 PM   #4
f2502011
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Quote:
Originally Posted by broncnaz View Post
26 is as hot as they sell in that size range. Are you sure that the 26 is what is recommended as stock? usually its 25 or 24's that are stock. I probably wouldnt bother with platinum plugs if the engine is carberated. just a waste of $$. You need to be very careful about running hot plugs as you can do more damage to the engine with hot plugs than cold plugs.
Here's the only chart that I could find I used to have one somewhere but couldnt find it. Your plugs in the upper right hand corner. http://www.cvproducts.com/upfiles/Autolite.pdf

If I go on autozone or oreilly's website and put in what vehicle I have (76 bronco) it lists only the autolite 26 or off brand equivalent.
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Old 01/09/12, 07:51 PM   #5
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gotcha just making sure. Actaully I got it kinda wrong on the numbers doesnt matter anyways 1976's use the smaller plugs than the earlier years. I know my 73 calls for 45's and 71 calls for 124's but I run 45's in the 71 as the 124's were just to cold when I idle for long periods if I get it out on the road some more I may need to switch back to the 124's.
Really if your fouling plugs then you have issues that need to be addressed by more than just a temporay bandaid.

73 Ranger 2 1/2 lift 302 TFS heads NP435,PS,PDB, tierod over, 33x10.50x15 BFG M/T
71 Sport 63,000 miles all orginal except for cut fenders 302 3sp 4.11's D44/BBTrac lok rear
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Old 01/09/12, 09:39 PM   #6
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Autolite 26 is a 14mm, .460" reach, 5/8" hex, tapered seat, power tip suppressor spark plug.

That is the second hottest spark plug available. There are only 2 hotter versions. Neither in the power tip. And the AP26 you have, the "P" is for Platnium. The fancy exotic metal tipped spark plugs are great for moder EFI engines, but old carbed engines they are a bit pointless.

OK, the hotter plugs. autolite 147 or 687 are the only hotter options that will fit your heads. The 687 is the wide gap version. Stock application is a '75 Checker.

All thanks to the phone book autolite catalog. The real paper catalog, not the online stuff.

"She's built like a steakhouse but she handles like a bistro"-Zapp Brannigan
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Old 01/10/12, 03:01 AM   #7
f2502011
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Great! Thanks for all the helpful info. I've got one cylinder (back passenger side) that will get oil on it if you run it for a bit. All the other cylinders burn clean. The strange thing is that it doesn't smoke when the plug is installed normally. I got a non-fouler just to try and when you first crank up with that after letting it sit for a bit it will let out a puff of blue smoke on that side. Not very much, but just enough to be able to smell burnt oil. I took it out after running for a long while mostly idling because I was tuning the carb and the bottom of the non-fouler had oil on it, but the plug was completely dry. I put the plug back in without the fouler and no smoke. It doesn't appear to smoke at all with either the plug or plug + non-fouler while driving normally. I need to borrow a compression tester to get more info on the condition of that cylinder and the others. I'm keeping my fingers crossed and hoping it's only valve guide seals. If everything checks out, the issue is fairly minor, and there are no issues with any other cylinders I'm considering just running a hotter plug on that one cylinder till the problem gets bad enough to warrant a full rebuild. What are your thoughts?
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Old 01/10/12, 08:37 AM   #8
broncnaz
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Unless that plug is actually fouling and its causing a miss fire I would keep it as is. if it is misfiring due to fouling then trying a hotter plug in that cylinder may help. Of course you have the non fouler so you could just use that instead of a hotter plug. No matter what that cylinder will burn oil all you need to do is make sure the plug keeps firing.

73 Ranger 2 1/2 lift 302 TFS heads NP435,PS,PDB, tierod over, 33x10.50x15 BFG M/T
71 Sport 63,000 miles all orginal except for cut fenders 302 3sp 4.11's D44/BBTrac lok rear
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