willysmjeeps.com

Assuming that number is stamped on your plugs?

That lookup yields a different NSN and part number (Autolite) BR4S. https://www.wbparts.com/rfq/2920-00-805-2646.html

Getting a feel for buying government surplus parts?

I sent this reply but it may be out of order in the thread ... or something.
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Using a loop, I see:

Autolite
MS35911-2
Resistor (In a script type font)


Also, I found a plug listing from another supplier (which may be wrong) that includes the MS35911-2 seen on the plugs I bought.

Autolite # BR4S, Champion # XED14, National Stk. #: 2920-805-2646, Mil. Spec #: MS35911-2.
_________________

Yes, saw it (we're both typing at the same time).

Not certain, but looks like maybe gasoline powered (early) M35 deuce and a half.

Hopefully Wes will straighten us out.....

I am going to wait for a response from the supplier which hopefully will resolve the problem.

So yet again, I am humbled by the (oh, what’s that big word no one hardly ever uses, hmmm) ...... ah, yes ...... humbled by the esoteric minutiae of this endeavor.

Yes, I'm humbled pretty regular. Thankfully, Wes is pretty gentle about it.

Almost as often as I'm confused, by words....

loop and loupe, for example.

loop and loupe.

#@$%@ spell checker didn’t cover my ass on that one.
Yes. Loupe.

Keep a few things in mind or focus here.

1 - Don has two entirely different spark plugs on those two photos of his.

2 - We have already pointed out that one (with 7/16" reach) has a longer reach then the 3/8" reach of the correct 2243. And now this new one BR4S which is an Autolite new # 2222 has an even longer reach at 1/2".

3 - Reach is an extremely important part of a spark plug specification since too long translates to impact damage to the spark plug/piston which can usually be interpreted as a spendy adventure in ignoring specifications/required clearances!

The second plug listed was from an ad I found for another plug

That ad used a description which included the actual markings stamped on the plugs I bought.... MS35911-2 which may not be relevant here.

Bottom line.

The plugs I bought (stamped MS35911-2) are not Autolite 2243 plugs and should not be used in my M38/ L-134 engine. (right?)

Yes. I missed this curve ball.

And with the BR4S (Autolite 2222) clearance-reach might not be the main issue? Unless you can screw an 18mm threaded plug into a 14mm hole?

Midwest Military supplied the plugs in question. If I supplied something other than the 2245 plugs that are currently available, it was unintentional. 2243 plugs are NOT manufactured by anyone any longer. Autolite and Champion discontinued them and scrapped the tooling. We have one plug available now, it is the 2245. This plug will fit and perform in the M38 and M38A1 without issue.
John

I could really, really use some more help on info related to this plug purchase.

The supplier tells me that he actually sent me “2245” plugs which are “Slightly hotter than the 2243.” Explaining that “2243 plugs are no longer manufactured by anyone.”

Here is what little I know.

The plugs are marked as Autolite MS35911-2
The supplier’s ad listed the plugs as 2243.
The supplier now tells me the plugs are actually 2245.

The supplier tells me 2243 plugs are no longer made, but I already knew that and was buying these plugs thinking that he had some 2243 plugs for sale which is what the ad reads.

So, I will ask the same question again for the third/forth/last time, just to be sure I am not being unreasonable or uninformed in my discussion with the supplier.

Are spark plugs marked “Auto lite MS35911-2” also known as “2245 plugs” ..
and are these plugs equivalent to 2243 plugs and proper for my M38?

>>>>. I just now read John’s response here and on ebay. I sure don’t know enough about this stuff to evaluate spark plugs. Help.

might shed some light on this


https://forums.g503.com/viewtopic.php?t=38913

Don,

Take a hard look at the last chart I posted. Look at the Autolite plug column for it's new 4 digit numbers. Now read down till you find 2245. Now read across to the left Ordnance Number column. Now write down that Mil Spec # MS35909-2 that applies to the 2245 Autolite #.

Now run your finger back over to the Autolite 4 digit column then down till you hit 2243. Now move across to the left again and write down That MS35909-1

Now go back to the 4 digit Autolite column and run up to the 2222 numer then move left to the BR4S # and then further left to the Mil Spec # MS35911-2. Write it down on your list.

There you now have a list of three different military specification numbers, none of which match and they do carry the same manufacturer's specifications either. However when the base MSXXXXX match and only the -X is different they can usually be substituted.

If the plugs in your original photo are stamped MS35911-2 then you cannot use them.

Mil Spec# MS35909-1 applies to Autolite plug 2243

Mil Spec # MS35909-2 applies to Autolite plug 2245

Mil Spec # MS35911-2. applies to Autolite plug 2222

“However when the base MSXXXXX match and only the -X is different they can usually be substituted. ” Wes

Don pauses for a minute and thinks:
John sent me plugs marked MS35911-2.
A M38 calls for Autolite 2243..... AKA. Mil Spec# MS35909-1
The two base numbers do not match therefore the plugs John sent me are not correct for my M38.

“If the plugs in your original photo are stamped MS35911-2 then you cannot use them.”Wes

But...... plug 2245/ Mil Spec # MS35909-2 would be OK.

How am I doing ??????
Will do a close up of the stamped plug #’s later. Don

what i find strange about this whole thread is that any spark plug I have ever bought had either 2245,or 2243 engraved right on the plug. The new production 2245's don't???