1941 and 1947 starter are they the same?

[caddyman20]

Hi.  I was hoping someone would know if a 41 cad with a manual transmission had the same starter as a 47 cad with a hydramatic?  Are they interchangeable?  Thanks in advance.

[Jeff Trahan]

I had a hard time figuring this out when installing the starter on my '47 (with Hydramatic).  The first one I bought, which was advertised to fit a '47, had a slightly different flange so the starter housing contacted the engine block when rotated into place before the mounting holes in the flange lined up with the holes in the transmission housing.  To make matters worse, the part number on the starter matched the correct '47 starter part number.  Unfortunately, someone had mis-labeled the starter and it was actually for some earlier model years.  I finally found the correct starter and it works fine now.  The correct part number for a '47 Cadillac is 1107931.  The part number for earlier Cadillacs (I think 1937-1941?) is 1107923.  I don't know if it matters which transmission the car has.

Jeff Trahan

[caddyman20]

From pictures they look really close to being the same. Only the brushes end of the starter looks different.  But from what you say and some other things on the net I'm starting to think they are different.  I'm surprised they are differnt tho with the engines being practically identical.

[Alan Harris CLC#1513]

My 1950 Motor Manual says 1107931 fits 1939-1948. Relying on this, I bought one of this number as a spare for my 1940. I haven't tried to change it, but it sure looks like the one on my car. The guy I bought it from said it came from a 1947.

[Steve Passmore]

The differences are in the bell housing bolt holes  , the later housings require the starter to be turned slightly making the earlier ones foul the block so they revised the end casting that fits through the bellhouseing.   I have overcome this in the past by swapping the end casting then drilling and taping the solenoid in its new position.
I think there has been a recent thread by Brad Ipsem on this subject,
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WTB: Starter Clutch Housing, 41 to 48

[Brad Ipsen CLC #737]

I'll repeat here.  41 to 48 starters will fit those years plus 39 and 40, but 39 and 40 do not fit 41 to 48.  Not sure about earlier years.  This is a good time to review again how the parts book does not give the whole picture.  A parts book from 1949 shows the same part number for 39 to 48 starters but that is from the perspective of a Cadillac dealer in 1949.  The starter they would have on the shelf would fit a 1940 Cadillac but it was not the same as a 1940 starter.  If you just looked at the parts book and had a 48 you would think you could put you 1940 starter in it.  This is not the case.  The difference is in the angular relationship of the mounting bolts to the solenoid.  There are many situations like this.  Cadillac would change things and the parts would fit earlier models.  They were not worried about year authenticity. 

[Alan Harris CLC#1513]

That makes sense. The starter on my 1940 does not have the oiler cups that are shown in the shop manual, so I figure that it is probably a newer replacement. The 1947 one I bought does not have the cups either.

The original must have had a different part number.

[joeceretti]

Interesting information. 38 and 39 starters are interchangeable, mounting wise, from my experience, on the V8.