Crossmatch spark plugs
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=153601
Printed Date: 04 May 2025 at 2:39am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Crossmatch spark plugs
Posted By: Ken McGregor
Subject: Crossmatch spark plugs
Date Posted: 02 Sep 2018 at 12:00pm
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I know someone has posted this in the past but I cannot find it. What number of NKG plug matches up to the AC 45C or Autolite 308 for use in an AC45 tractor. I need something with a little more quality since the other plugs don't seem to last or work very well any more. Thanks for any assistance regards, Ken McGregor
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Replies:
Posted By: HudCo
Date Posted: 02 Sep 2018 at 12:40pm
| by book says ngk b2 or stock #31110 . my 2 cents worth is that if plugs arnt lasting the problem is some where else coil , condensor voltage to assuming this has distributer not a mag or compression problems |
Posted By: Alvin M
Date Posted: 02 Sep 2018 at 2:46pm
| I Use Autolite AP86 Work Good For Me Used Them For 15 years |
Posted By: Ken McGregor
Date Posted: 02 Sep 2018 at 2:54pm
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Any comments on using NKG XR41X/7189 or NKG B6ES? regards, Ken McGregor
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Posted By: DougS
Date Posted: 02 Sep 2018 at 3:45pm
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The XR is a resistor plug. Go right ahead and use it if your tractor doesn't have a magneto. Edit: Have a look here.. http://www.clubplug.net/assets/pdf/cross-reference-ngk.pdf" rel="nofollow - http://www.clubplug.net/assets/pdf/cross-reference-ngk.pdf |
Posted By: mdm1
Date Posted: 03 Sep 2018 at 4:38pm
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I started using B-4's in all the tractors. So far happy with them. ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: DougS
Date Posted: 04 Sep 2018 at 6:39am
Autolite 306 seems to cross better. It's a hotter plug. The lower the number (goes for NGK too), the hotter the plug. Switch up or down one number, depending on what you see at the end of the plug life. |
Ken McGregor wrote:Posted By: Phil48ACWC
Date Posted: 04 Sep 2018 at 6:40am
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https://www.rockauto.com/en/parts/ngk,7189,spark+plug,7212%20" rel="nofollow - https://www.rockauto.com/en/parts/ngk,7189,spark+plug,7212
Click on above. Best plug and best price. NGK Iridium. I have these in my WC with WD45 Crank and WC pistons and rods. Makes 8:1 compression ratio. Also have distributor with Pertronix electronic ignition conversion and heavier advance springs to delay advance curve to avoid pinging on regular gas when the engine gets bogged way down. When I first built the engine, I put a brand new set of Autolites in and had misfires within less than 1 hour run time. Iridium is the only way to go. I now have 50 hours on the Iridium plugs and they run great. They are more expensive but they last practically for ever.
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Posted By: DougS
Date Posted: 04 Sep 2018 at 6:54am
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Expensive plug indeed. You can buy 4 regular plugs for the price of one iridium. Iridium plugs will still foul, so don't waste your $$ there if your tractor uses oil. Copper plugs still fire the easiest. I'd recommend that you stuck with copper if you are running standard ignition. Your XR4 is a resistor plug. Not recommended for magneto-equipped ignition systems. |
Posted By: Phil48ACWC
Date Posted: 04 Sep 2018 at 6:59am
| The plugs I had in there were Autolite 303. Terrible. Love the NGK Iridium. |
Posted By: Butch(OH)
Date Posted: 04 Sep 2018 at 7:11am
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You didnt ask these questions but since others mentioned them I used Autolites for years after AC quit making the 45 but when they switched to China I had 3 bad sets in a row,,no more Autolites for me. There are still LOTS of NOS AC45 plugs around for sale and they work just as well now as they did back in the day. A few years ago I kept A-C 45, AC45, AC-45 etc as saved searches on Ebay and quickly bought up a lifetime supply (X5) of plugs. Dont get discouraged when you first look, there are quite a few for sale at very high prices, just save the search and be ready to buy when they show up for sale at decent prices. Be aware that there are China reproduction AC45 on the market also, I have no experience with them |
Posted By: DougS
Date Posted: 04 Sep 2018 at 7:21am
| Not intended as a political comment, but I wish the tariffs were applied to finished products, not raw material. That might bring the plug manufacturing back to the US. |
Posted By: Phil48ACWC
Date Posted: 04 Sep 2018 at 11:09am
| Yup, Chinese and Taiwanese plugs whether they are AC, Autolite, Champion or whatever, are junk. NGK Iridium are pricey but I haven't found a bad one yet and I bought 28 of them so far. |