Sparg plug

Standa · Post by **Standa** » Sun May 19, 2013 1:44 am

Hello,
I got to the M38 spark plug.
I do not fit there.
They designation AUTO - LITE AR8S
Do you know what cars have to be?

Post by **wesk** » Sun May 19, 2013 2:37 am

Hello Standa,

It is a military plug and is not used in civilian vehicles. It is still in production by Autolite but under it's newer number 2246. Substitute numbers for it would be:
AC Delco SR47E
Autolite 2246
Blue Crown SR6F14
Champion XEJ12
Champion stk 567
General Motors 5612829
Stitt S47-5MC

The correct plug for the M38 is Auto-Lite AR5S or new Autolite # 2243.
Other numbers that it may be found in new old stock sources from surplus dealers are:

Champion XMJ-14
AC WR44
Mil Spec # MS35909-1
Ordnance # 7524258

Bretto · Post by **Bretto** » Sun May 19, 2013 7:33 am

Out of curiosity, do the mil-spec plugs have the same electrode and thread end as a civy plug? Meaning other than the wire terminating end, are they the same?

Post by **wesk** » Sun May 19, 2013 9:09 am

Yes they are they equivalent of the J8 series used in the MB and CJ flatheads.

Standa · Post by **Standa** » Sun May 19, 2013 11:14 am

Thank you for your help.
I know what I buy.
I'll look into what the car's spark plugs are

MrWillys · Post by **MrWillys** » Thu Aug 08, 2013 7:14 am

wesk wrote:Hello Standa,

It is a military plug and is not used in civilian vehicles. It is still in production by Autolite but under it's newer number 2246. Substitute numbers for it would be:
AC Delco SR47E
Autolite 2246
Blue Crown SR6F14
Champion XEJ12
Champion stk 567
General Motors 5612829
Stitt S47-5MC

The correct plug for the M38 is Auto-Lite AR5S or new Autolite # 2243.
Other numbers that it may be found in new old stock sources from surplus dealers are:

Champion XMJ-14
AC WR44
Mil Spec # MS35909-1
Ordnance # 7524258

Can I use these for my 43 MB?

Post by **wesk** » Thu Aug 08, 2013 7:57 am

If a 45 MB were set up for waterproof ignition with the M38 type spark plug leads then the M38 plugs will fit. 2243 or 2245. If the AR8S (2246) has the same upper barrel you could use it as well but it would be a very hot plug for your application. You would have to lay a AR8S (2246) along side either of the M38 plugs and measure the depth of the inside of the upper barrel and the thread size on the upper barrel.

MrWillys · Post by **MrWillys** » Thu Aug 08, 2013 9:22 am

A lot of the brands you have in the US are not available here. I did a check of the plugs that are in the car, they are Champion J6C. The NGK equivalent is NGK B6S. Both brands are common here, so I should be able to find one of them.
Thanks!

MrWillys · Post by **MrWillys** » Wed Aug 14, 2013 11:49 am

Changed the spark plugs with new NGK plugs.
I checked the old plugs, and I have to say I have never seen plugs looking so healthy as the ones I removed. Rusty on the outside, and a nice light brown color on the inside. I have seen a lot of spark plugs, but these scream healthy engine x 4.
Nice! Engine seems to start up a bit easier now as well!

Post by **wesk** » Wed Aug 14, 2013 12:02 pm

Glad she runs well for you.

MrWillys · Post by **MrWillys** » Wed Aug 14, 2013 12:09 pm

Not as happy as I am!