M38 Engine Dilemma; Thinking on G503

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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dpcd67
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M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Sat Jan 28, 2017 3:37 pm

Situation; I have a June 51 M38; it has a RMC engine SN 124184, part number 804380 on it. The one with the rust and aluminum balls in the cylinders. It has the bell housing and starter.
I also have a spare RMC engine; SN 56788; part number 64xxxx; turns freely. I learned that they are different engines; the early ones use ten bolt bell housings and different starters. No bell housing or starter on this one.
I was going to put the earlier engine in, but now I see the bell housing and starter won't fit; I am now inclined to rebuild the late one, rather than find a bell housing and starter. (Actually, I think I have a bell housing here somewhere. )
Mission: Choose an engine for my M38.
Anyway, I am leaning to using the late engine because I have never seen one and to have one in my M38 will be cool. I know, that is not a good reason. I was going to put this in a 5 paragraph field order format but forgot about it half way through.
Comments or snide remarks welcome.
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Re: M38 Engine Dilemma; Thinking on G503

Post by Joe Gopan » Sat Jan 28, 2017 7:46 pm

Late Bellhousing and the Matching Rear Plate will bolt right up to earlier engine with 124 Tooth Ring Gear, but you have to use a 129 Tooth Ring Gear and the late starter that is attached with 1/2" Bolts.

Remember, you will need the late adaptor plate,129 tooth ring gear and late Starter. The late Bellhousing, Adaptor Plate, Ring Gear, and Starter are same as M-38A1.
The ORD 9 SNL G-740 dated 1956 will confirm this.
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Sun Jan 29, 2017 10:00 am

Ok so as long as I change everything from the newer one to the early one it will work. The early one has no starter, bell housing or flywheel anyway. Good to know. Of course I read my SNL every day but I didn't think to check this out . Let that be a lesson to everyone. Study.
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Re: M38 Engine Dilemma; Thinking on G503

Post by Joe Gopan » Sun Jan 29, 2017 10:07 am

CJ-5 F-Head Bell housing and adapter Plate and 129 Tooth Ring Gear will work and the Late M-38/M-38A1 starter is a match for these parts. Stick with what I mentioned as CJ-3A and CJ-3B components were not always a match til early 53.
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Sun Jan 29, 2017 12:24 pm

Ok now you are confusing me with the cj5 and 3 talk. Am I reading this right; I can use the bell housing , engine plate, starter and flywheel now installed on the RMC 124000 motor, on the RMC56000 motor without any issues. Yes or no?
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Re: M38 Engine Dilemma; Thinking on G503

Post by Joe Gopan » Sun Jan 29, 2017 2:35 pm

You can use the late bellhousing , plate and Starter on the early engine and vice versa. Later set up has a better starter. Remember to match ring gears with the set up you choose.
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Sun Jan 29, 2017 7:28 pm

Good. I only have the late setup so that solves the starter thing. Anyway it is good to know that I can use either block.
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Re: M38 Engine Dilemma; Thinking on G503

Post by DieFledermaus » Mon Jan 30, 2017 3:42 pm

And just to complicate things, I have the early bellhousing, starter, and flywheel/ring gear for it should you want to go that route.
-Mike
AUG 1944 MB, US NAVY
MAR 1952 M38
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Mon Jan 30, 2017 4:12 pm

Good to know. If I decide to use the late block, and I want to only because it seems unique, and if it is cracked or something(Abrahams machine shop will magnaglux it), then I might need your parts. But from what I see, the new parts are backwards compatible onto old blocks.
Still not as much drama as restoring WW2 jeep!
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Re: M38 Engine Dilemma; Thinking on G503

Post by DieFledermaus » Mon Jan 30, 2017 5:39 pm

I prefer the late set-up. The early starter switch was subject to moisture problems but if you are not fording creeks and swamps, I'm sure you'll be fine.
Cheers
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Mon Jan 30, 2017 7:40 pm

We have no creeks or swamps here; just corn fields and hogs. The Mississippi is frozen over though....
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Tue Jan 31, 2017 3:16 pm

I discovered today that my late engine has the dreaded death crack under the distributor. It can be fixed but I will use the good, earlier, one.
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Re: M38 Engine Dilemma; Thinking on G503

Post by DieFledermaus » Tue Jan 31, 2017 4:06 pm

I'll get out the parts you need.
-Mike
AUG 1944 MB, US NAVY
MAR 1952 M38
APR 1952 M38
1957 F2A AERODROME TRAILER
1993 M101
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Re: M38 Engine Dilemma; Thinking on G503

Post by dpcd67 » Tue Jan 31, 2017 5:57 pm

Wait. Thanks but the new type parts on the 804380 number (cracked) engine will fit on the older 641087 engine if I read Joel's posts right.
Am I right?
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Re: M38 Engine Dilemma; Thinking on G503

Post by DieFledermaus » Tue Jan 31, 2017 9:49 pm

In this discussion, the blocks are the same in the sense they will accept either early or late parts. If you have a late bellhousing, late starter, and a late flywheel (129 teeth, 13" diameter), then yes, you don't need anything from me.
-Mike
AUG 1944 MB, US NAVY
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1957 F2A AERODROME TRAILER
1993 M101
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