Autolite plugs
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Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
Autolite plugs
as long as we're talking about these, here is some more info.
there is an old paul yaw article floating around where he likes them with the MSD. that and the 2.89 price is good.
the BAD:
the parts store computer screen says these are pre gapped to .055". this would be nice if it was true, out of 8 plugs 2 were at .055, 3 at .047, 1 at .045 and 2 more were in the low .040's. so you have to match them up, the big ones can go in the trailing, its more shrouded there. small ones in the leading, you want them to actually fire.
also the threads on these things suck, would not be a bad idea to run it thru a thread die before you install them.
and also since its autolite, you need to triple check to make sure its the right plug, check the box, check the stamp on the plug, and then compare plugs!
all these things we take for granted with NGK
there is an old paul yaw article floating around where he likes them with the MSD. that and the 2.89 price is good.
the BAD:
the parts store computer screen says these are pre gapped to .055". this would be nice if it was true, out of 8 plugs 2 were at .055, 3 at .047, 1 at .045 and 2 more were in the low .040's. so you have to match them up, the big ones can go in the trailing, its more shrouded there. small ones in the leading, you want them to actually fire.
also the threads on these things suck, would not be a bad idea to run it thru a thread die before you install them.
and also since its autolite, you need to triple check to make sure its the right plug, check the box, check the stamp on the plug, and then compare plugs!
all these things we take for granted with NGK
in the article, did he articulate why he felt that they were better with an MSD setup (other than price)? i'm just curious. i still wouldn't use them, but i'd like to hear if there was some quantitative finding on his part.
Joined: Feb 2006
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From: London, Ontario, Canada
Given that NGK's work, Mazda recommends them, and I want my next engine to last at least one week after it's finished, I'll just shell out the $100CDN for the 4 NGK's.
Joined: Jun 2008
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From: Chino Hills, CA
I used the autolites a few times back when I was poor & the -7 was my DD; they worked okay, but fouled quickly, IIRC. & I never relied on pre-gapping with gappable plugs; they'd often get smooshed in shipping. Always re-gapped mine.
Wrkn Toyota, Rootn Wankel
Joined: Sep 2007
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From: "Haystack" Hayward, CA
I personally used the Autolites in my RX7 before I wrecked it, ran perfectly fine, though the plug fouling seems to be true.
My only concern and it was reinforced by another member, albeit his situation was different, that since they are traditional prong spark plugs they could, if improperly installed, wrong part, or god just hates you, take out the apex by accident.
I am going to run NGK Plugs from now on because I like how their design really eliminates the worry of that issue.
My only concern and it was reinforced by another member, albeit his situation was different, that since they are traditional prong spark plugs they could, if improperly installed, wrong part, or god just hates you, take out the apex by accident.
I am going to run NGK Plugs from now on because I like how their design really eliminates the worry of that issue.
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From: https://www2.mazda.com/en/100th/
http://www.rhinoracing.com/yaw/ignition.htm
Spark Plugs
I have been doing some spark plug testing recently, and have been surprised at the results. I have been doing this testing on my daily driver, a bridge ported 13B. Almost everything starts here, and then makes its way to the dyno if the results seem worthwhile. In this engine, I have had the best luck with the Autolite 2526. You know, those cheap nasty plugs that they try to sell you at the discount auto parts store. These plugs have only one ground strap, instead of four like the NGK, or ND plugs. If you look at one of these, it makes sense that they would produce more power because the spark is much less shrouded. This will allow the flame to travel more easily from the face of the plug to the combustion chamber which is a big problem with the rotary anyway.
I should mention that these plugs do not work well without an MSD. It seems that the gap is to great for the stock ignition system to fire consistently. I found that with an MSD on the leading, and stock ignitor on the trailing, that these worked better in the trailing position than the NGK's. However,a friend with a completely stock ignition found that they just plain didn't work as well as the NGK. Until I have a chance to check this out myself, I will not reccommend them for stock ignitions.
Spark Plugs
I have been doing some spark plug testing recently, and have been surprised at the results. I have been doing this testing on my daily driver, a bridge ported 13B. Almost everything starts here, and then makes its way to the dyno if the results seem worthwhile. In this engine, I have had the best luck with the Autolite 2526. You know, those cheap nasty plugs that they try to sell you at the discount auto parts store. These plugs have only one ground strap, instead of four like the NGK, or ND plugs. If you look at one of these, it makes sense that they would produce more power because the spark is much less shrouded. This will allow the flame to travel more easily from the face of the plug to the combustion chamber which is a big problem with the rotary anyway.
I should mention that these plugs do not work well without an MSD. It seems that the gap is to great for the stock ignition system to fire consistently. I found that with an MSD on the leading, and stock ignitor on the trailing, that these worked better in the trailing position than the NGK's. However,a friend with a completely stock ignition found that they just plain didn't work as well as the NGK. Until I have a chance to check this out myself, I will not reccommend them for stock ignitions.
Thread Starter
Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
thanks, j9fd3s. your last post gave a weird deja vu-thing. 
that was a pretty good read. i thought i had read all of Yaw's stuff, but i guess not. anyway, doesn't he go on to conclude that the NGK BP_ES shares a similar design, but was stronger?
that was a pretty good read. i thought i had read all of Yaw's stuff, but i guess not. anyway, doesn't he go on to conclude that the NGK BP_ES shares a similar design, but was stronger?
Joined: Jun 2008
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From: Chino Hills, CA
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Joined: Nov 2002
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From: Grand Junction Colorado
Right now I'm running NGK BR_EIX it's the Iridium. It has a single electrode, and a very thin center electrode. they are supposed to spark very easy and resist fouling.
what are the thoughts on these. so far the are doing well for me. '85 GSL 12A.
what are the thoughts on these. so far the are doing well for me. '85 GSL 12A.
well, it's one of the plugs that i use and have been doing so since about 2002. i can vouch for them being more foul-resistant than the stock plugs. i think they are phenomenal.
Thread Starter
Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
hmm, the its not in that link i posted, so i dunno. its obviously not very current. the bp_es plugs are cool cause they come in a bunch of heat ranges
sorry for the long quote, but at the bottom of your link he says this:
ANOTHER Spark Plug Update 6-22
OK, here we go again. As I mentioned before, the Autolite didn't last long. The Champions were even worse, and turned out to be quite fragile. I finally scrounged an NGK Sportline Catalog from a local motorcycle shop, and guess what I found. A 14mm., .750 reach, extended tip plug. BP-ES Pay dirt! Same design and dimensions as the Autolite and Champion extended tip plug. After performing the same modifications I installed them, and beat them to death. They are very tough. Just to be sure, I installed a BP7ES in the leading position which is a bit hot for an extended tip plug. I have driven around with these 7's installed for nearly a month now, and even gave them the torture test by running 90mph on the freeway for several miles. This is normally no big deal, but since the plug is too hot for this application it really put them to the test. After this I examined the ceramic with a magnifying glass, and could see no signs of cracking. The performance is the same as the other extended tip plugs, but they are much more durable. They are available at most motorcycle shops in two different heat ranges. BP7ES, and BP8ES. A BP9ES is also available, but the local shops do not stock it. They can be ordered however. The only downside is that they are a 13/16 short shell plug, and you will need a Racing Beat spark plug socket to install them.
OK, here we go again. As I mentioned before, the Autolite didn't last long. The Champions were even worse, and turned out to be quite fragile. I finally scrounged an NGK Sportline Catalog from a local motorcycle shop, and guess what I found. A 14mm., .750 reach, extended tip plug. BP-ES Pay dirt! Same design and dimensions as the Autolite and Champion extended tip plug. After performing the same modifications I installed them, and beat them to death. They are very tough. Just to be sure, I installed a BP7ES in the leading position which is a bit hot for an extended tip plug. I have driven around with these 7's installed for nearly a month now, and even gave them the torture test by running 90mph on the freeway for several miles. This is normally no big deal, but since the plug is too hot for this application it really put them to the test. After this I examined the ceramic with a magnifying glass, and could see no signs of cracking. The performance is the same as the other extended tip plugs, but they are much more durable. They are available at most motorcycle shops in two different heat ranges. BP7ES, and BP8ES. A BP9ES is also available, but the local shops do not stock it. They can be ordered however. The only downside is that they are a 13/16 short shell plug, and you will need a Racing Beat spark plug socket to install them.
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From: Grand Rapids Michigan
Seems I remember that he modified his plugs by cutting the strap to create a "side fire" plug. Is that correct, or am I thinking of someone else?
"After performing the same modifications I installed them, and beat them to death"
"After performing the same modifications I installed them, and beat them to death"
Thread Starter
Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
whats wrong with these? http://www.ngk.com/more_info.asp?AAIA=&pid=2410
$7 each... come in cold heat ranges
Part Number: R6254E-105
Stock Number: 3949
$7 each... come in cold heat ranges
Part Number: R6254E-105
Stock Number: 3949
they sound like they'd be great to try in turbo and race engines. i'm skeptical about them being hot enough for lesser applications. however, that's just conjecture since i've never used them.
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