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Spark Plug Thread Size??
Working on getting my ‘62 M37 going, I went to replace the plugs and the ones that the guy gave me when I bought the truck are way too big. What is the correct plug for an M37? These are the waterproof type plugs.
Re: Spark Plug Thread Size??
Plugs are 14mm.
The stock waterproof plug is an Autolite AR5S (alternate number is 2243), which is a cold range plug. These were also available as AR4S / 2242 (colder), AR6S / 2244 (cold/medium), and AR7S / 2245 (medium temp).
Champion, and possibly other manufacturers, made similar waterproof substitute plugs.
Since the originals were discontinued several years ago, they can be harder to find, especially at a reasonable price. They were reproduced, but I recall that those have been problematic. A search here will reveal more.
The stock waterproof plug is an Autolite AR5S (alternate number is 2243), which is a cold range plug. These were also available as AR4S / 2242 (colder), AR6S / 2244 (cold/medium), and AR7S / 2245 (medium temp).
Champion, and possibly other manufacturers, made similar waterproof substitute plugs.
Since the originals were discontinued several years ago, they can be harder to find, especially at a reasonable price. They were reproduced, but I recall that those have been problematic. A search here will reveal more.
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Re: Spark Plug Thread Size??
I wonder what the larger size was for? I guess maybe a bigger vehicle? Or an earlier vehicle. The thread size reminds me of the plugs that fit my old Farmall tractor. I will be putting these ip for sale on ebay. I have to recoop some of the money to pay for the new ones ($192 plus shipping)!
Re: Spark Plug Thread Size??
The number of this plug is 2225. Thread size is 18mm
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