Bell housing gaskets, Oil filter, help

1951m38 · Post by **1951m38** » Wed Jan 14, 2015 10:29 am

Hello,

I'm finally able to get to my M38 project after a 12 year child raising hiatus !! She is actually pushing me to get the project going again !!! That said I have some questions I'm hoping folks can help me with.

The Jeep is s/n is MC31128 and the engine is MC38724 it has the tar like under coating under it and the paint (what's left) has a blueish tint to it so I'm pretty sure it was one of the USMC jeeps.

I try to make/keep the jeep reasonably correct. I don't plan on driving it underwater but it probably will see some rain as I live in NW PA. I plan on hooking up the fording valves, piping and cabling to look/be correct but do not plan on using it.

1st is in regards to the Transmission bell housing gaskets.

The org 9 book lists

Gasket, transmission case to bell housing WO 640351 after s/n 53261 pg 190 ( I installed the round one 640425 on the input shaft bearing retainer when I went through the transmission)

Gasket, block to bell plate adapter pn 804379 used after engine serial MC74419 pg30

Gasket, bell plate to housing PN 804377 used after engine serial MC74419 pg30

Obviously my jeep is well before those serial numbers. So does that mean the are NO gaskets in those three places ?

Same for the clutch inspection cover ? and starter motor? NO gaskets ?

2nd Oil filter / screen.
The jeep had a CUNO p/n 7375060 screen filter with it. The Org 9 book page 44 lists pn 540501 Can filter element type as being used in this jeep ,i.e., used after after s/n 28132. Seems like the Canister type is probably a much better filter so should I hunt for this type or could the cuno have really came on the vehicle and I should just stick with it ?

3rd
What color was the master cylinder heat shield. OD, natural, Black ?

4th
There are two studs coming out of the engine block maybe 10-24 size to the rear of the distributor what are they for ?

Thanks in advance !!!
Tim

4x4M38 · Post by **4x4M38** » Wed Jan 14, 2015 2:56 pm

Hi Tim,
I can't help with much here as my experience is limited.

I did find in Wes' photo pages and in the TM engine and clutch manuals some images of the right side of the engine.

It appears at one point that provision was made to install the oil pressure sending unit at those two 10-32 screws behind the distributor.

ORD 9 SNL G-740 published Sept 1955, TM9-8012 published January 1956 and TM9-1804A published June 1951 all on line here show the sender at the left rear of the engine in several diagrams. However, Wes' photo pages show numerous 641087 early blocks with those studs there in actual photos as well as ORD pages.

Interesting question.

Take care,
Brian

RICKG · Post by **RICKG** » Wed Jan 14, 2015 3:00 pm

It seems to me the 2 studs in question were for the civvy ign coil bracket mount. (question #4)

1951m38 · Post by **1951m38** » Wed Jan 14, 2015 3:21 pm

I also thought it might be mounting for the ignition filter used on early M38s but I think I read it was mounted on the firewall ?

Tim

4x4M38 · Post by **4x4M38** » Wed Jan 14, 2015 3:39 pm

Hi Rick!

Staying warm?

I agree since the M38's shared much with the CJ's. It wouldn't be the first time we've seen crossover stuff. The spare tire bracket holes in the right rear fender on the M38's come to mind.

There are several images in Wes' pages showing the oil sender up there instead of bottom left. However, most of the wiring diagrams I've seen for the M38's show the sender wire going around the left side of the engine.

Take care,
Brian

1951m38 · Post by **1951m38** » Fri Jan 16, 2015 3:16 pm

Update.

Looks like the consensus is that the 2 studs are for the civilian coil. Don't remove them as they go into the water jacket.

The early M38 below ~74k had an unsealed bell housing and did not have gaskets. in fact the inspection cover has louvers on it.

The heat shield on the Master cylinder is typical OD.

and the CUNO oil filter is in fact a very good filter if the instructions on using it are followed. Give my S/N and the typical depot work do while in service it my have come with a canister, but it is entirely possible the CUNO was changed while service was being done if the filter elements where not on hand.

At least that is what I have found so far.

thanks everyone for their input.

Tim

1953 M38
Bantium T3-C trailer
1941 J3 cub
1953 L21B Liason plane (supercub)

RICKG · Post by **RICKG** » Fri Jan 16, 2015 4:42 pm

Keep the cuno, Tim, theyre as effective a filter as ever designed and you wont be buying filter elements 2x a year.. post some pics of your stuff!!
I wanna see the M38 in the same frame with the J3 and L21B!!

Post by **wesk** » Sat Jan 17, 2015 1:22 am

The serial notes on the Cuno filter in the parts manuals are errors. The entire M38 production run used Cunos. The early M38A1 used Cunos. The 6 prototype M38's may have all came with Military Juniors.

The key to always follow on the bell housings is not so much the serial listing in the parts book as what you have on the jeep. Switching around to match parts book serials can get expensive. Both early & late engines will bolt to both early and late bell housings/adapter plates.

The back end of the early engine has four 3/8" bell bolt holes.

The back end of the late blocks have four 3/8" bell bolt holes and six 5/16" bell bolt holes.

On M38's the oil pressure sender was always down low on the left rear of the block. The two studs were not used for anything on the M38's.

TomM · Post by **TomM** » Sat Jan 17, 2015 7:53 pm

Tim,
Re: bellhousing gaskets. There was a major revision of the fording vent system around engine s/n 74k as noted in the parts book. The M38 went from an open bellhousing with no gasketing to a closed bellhousing with everything gasketed. The fording vent pipe system on late closed system joined the transmission + transfer case + bellhousing.
If you still have the early system which is identified by Wes's engine pictures the bellhousing will be similar to the period civilian jeeps.

Tom

Post by **wesk** » Sun Jan 18, 2015 2:06 am

The differences between bells are shown well in my photo album under M38 running gear pages 2 & 3.

http://www.willysmjeeps.com/v2/modules. ... php&page=2

http://www.willysmjeeps.com/v2/modules. ... php&page=3

Keep in mind that the two bell housings have there own starters and that in most early bell housings the late 229 tooth flywheel won't fit well and the starter for the 229 tooth flywheel will not fit at all in the early bell.

But we are throwing a lot of info at you that could be reduced by letting us know exactly which components you have.

1951m38 · Post by **1951m38** » Mon Jan 19, 2015 6:40 am

Thanks for the information everyone. Here are some photos of the block, bell housing and starter. I counted the teeth on the flywheel and there are 224 by my count. Is that correct for the early starter.?

More questions...
The extra bolt hole in the back of the block to the right of the accelerator mounting bracket holes looks like it just gets a 1/2 -20 bolt how is it sealed rubber washer ?

Does anyone know where this goes? Photo's would be great. I think it goes with the rear Transmission cushion ?

Thanks Tim

Post by **wesk** » Mon Jan 19, 2015 6:46 am

97, 224 & 229 are the three magic numbers for the 4 cylinder 1941 thru 1971 jeep universal flywheel ring gears.

224 is correct for the equipment in your photos.

Yes it is part of the rear powerplant support to the rear crossmember

1951m38 · Post by **1951m38** » Mon Jan 19, 2015 6:50 am

Rick, Here's a couple of photos of the 1953 L-21B I need to get the jeep a little further along to get them together in a photo but that is the plan. The J3 is also a project (after the M38 !!!)

PS I hope it's OK to post the plane pic here

Tim

1951m38 · Post by **1951m38** » Mon Jan 19, 2015 6:53 am

Here is the frame and the engine front so far. Thanks again for every ones help !!!

1951m38 · Post by **1951m38** » Mon Jan 19, 2015 6:54 am

Thanks Wes !!!