Engine serial number

idiocrates · Post by **idiocrates** » Mon Jan 05, 2009 9:30 am

I finally got enough of the gunk off my F-head engine to discover that there is no engine serial number on the flat landing immediately below the thermostat housing. Could this mean this block has been decked and the serial number cut away? Was the number restamped anywhere else on these engines when this happened? I'm working on the casting number on the right side of the engine now and will repost once I have this info in hand. Incidently......this is an m38a-1 with no tub serial number plate as well. Thanks.

Jim

whydahdvr · Post by **whydahdvr** » Mon Jan 05, 2009 10:42 am

I have the same issue on my M38. The data plate has an "odd" number, no secondary data plate, and the engine block number isn't there. I've asked Wes and Ryan about this and how to find out the correct info and it seems there are no other options.

Post by **wesk** » Mon Jan 05, 2009 11:06 am

Correct, if there is no number remaining on the flat above the water pump the block deck has been ground off.

In rare cases some military overhaul and repair facilities would stamp a copy of the vehicle serial number on a frame rail or elsewhere when they had the jeep disassembled since the only factory serials are on the two removable dash and tub plates. Engines overhauled by military depots had a metal tag affixed to the block with the facility's ID, the date, the engine serial and any over or undersizes.

It is unfortunately a fact of life that it your jeep has none of the above then you have an unidentifiable jeep. All that can be done is to narrow the dat of delivery down to a reasonably sized period based on attributes that changed during certain times in production.

idiocrates · Post by **idiocrates** » Mon Jan 05, 2009 1:24 pm

Thanks, guys. Maybe this was just somebody's way of prodding me into cleaning up the frame too in my pursuit of info. Now my dilema is.....if the block has been ground down before.....if necessary.....can it be decked a second or possibly third time? Maybe this is why no one has bothered to overhaul this engine again and allowed it to get so gunked up. Las thing I want to hear from the machine shop is that this block is kaputt. Wish me luck!

Jim

Post by **wesk** » Mon Jan 05, 2009 1:41 pm

There is a finite limit to how much metal can be removed from the deck. In really bad cases the in the block valve stems have to be shortened.

Jim · Post by **Jim** » Mon Jan 05, 2009 9:00 pm

Just as an off chance, clean the area with
solvent, dry it, and then brush on some
graphite with a dry brush. There might be
enough 'memory' spots left to show some
of the serial numbers.

Jim in Darkest Arkansas

jam51m38cdn · Post by **jam51m38cdn** » Thu Jan 08, 2009 11:05 am

Try checking with a law enforcement detective, If I remember right they used to use an acid and brush it on areas where serial numbers had been ground off by criminals and it would make the serial numbers reappear due to the metal being stamped. And of course to nuetralize acid , use baking soda and water mixed

DaveM38A1 · Post by **DaveM38A1** » Sat Jan 10, 2009 6:46 pm

The serial number was gone on my M38A1 engine, but there was a a rebuild tag on the right side of the engine just above the oil pan. The inspectors used it to get me the title in my state. The engine on my 64 CJ5 is there and quite readable. My guess is that when the army rebuilt the engine in 57, they ground off the numbers, and relocated the plate. I have another engine the PO gave me with no numbers on the block above the water pump.

Dave