HiYa Gang-
This issue has to do with the oil filter housing for the N-Series Tractors, beginning with the 9N. The picture is from the Robert N. Pripps' book, "How To Restore Your Farm Tractor", c 1992 MBI Publishing, ISBN 0-87938-593-6, and shows the oil filter housings for the N's. Bob Pripps followed the late Palmer Fossum around when he was restoring his *9N357*. He states the rounded bottom one is correct for the early 9N and the "scallopped" one is for the later N's. The question is when was the rounded bottom style obsoleted. The March 15, 1940 Master Parts Price List Book states the oil filter housing as part number 9N-18658. The part number is also the same in the '41 and '42 MPB's. The January, 1946 MPB shows the part number changed to 9N-18660 and covered 39-45. The July 1947 MPB also lists the housing as part number 9N-18660 '39-'48. I don't have access to any MPBs from '43; '44, or '45. This would be interesting to see how many rounded bottoms are out there and if we can nail down the date this change was made.

Tim Daley(MI)

...here are some pictures of my 9N and 8N housings...the 9N lines go directly into block under the housing and then around to the governor. The scallops are wider on the 8N housing. The 8N has a drain plug and one line snakes around to the junction block on the opposite side while the front line goes to the governor. If anyone has a picture of the round-bottom housing please post with your year/model. The 9N is a '39 and the 8N is an early '48 ( Cast code of September '47 ). Does this mean that the statement in the Pripps' book about the early housings being the round-bottoms is not neccessarily true? Or that several vendors were used throughout production years? Just curious as I am restoring my early 9N and I believe all parts to be original.

Early 9N s/n *9N653I*-

Early '48 Hsg. s/n *8NI55I3*-

Tim Daley(MI)

I would bet that it is a manufacturing advance. When you get a chance check one of the smooth bottoms, likely it is welded on if not it was spin shaped. Either process would be more expensive than stamping. The scalloped housing could be the result of stamping and the scallops are where the extra metal went. These are Pure-O-Lators for the most part and if the process changed it could meet Ford criteria with no design change. I often wonder why in later N's there are housings with drain plugs, some without and again some with.

9N295654 (1947 2N) had the scalloped can, in case that helps.

Another change: didn't the design for the oil filter change at some point to include provision for an oil line to the governor? When did that change happen? Did it happen at the same time as the change from round bottom to scalloped bottom?

Round bottom vs scalloped bottom....hmmm, that brings up another question that I'd better not post!

If it helps any 9N35981 has the round bottom housing.

Tim....it seems you are comparing apples to oranges.I think the correct part number for just the housing and bracket is 9n18658.According to my 1944 parts book,his item was not serviced separate after 1943.The 9n18660 part number is the housing,bracket, and most other parts that go to make up a complete assy.including a cartridge.This is shown on page 69 of the 1946 parts book.This part number is also shown on page 30 of the 1940 parts book.As for when they changed the housing itself,I don't know.When I restored my 39,I replaced my housing with an NOS 9n18660 housing assy. with the scallops on the bottom,but I don't know when the housing was actually made. don b

I think what Don says is correct. The 9N-18660 drawing of the complete assembly was released in May '39. It was revised many times up to 1943, but not replaced or it would have been destroyed. There is no evidence of of the "scallops", so they are probably a tooling device to aid a supplier. There is a label shown on the cover which has a Ford script, and very hard to read, but looks like a suppliers name "FLECSING MFG CO. E. Providence, R.I.

"There is no evidence of of the "scallops", so they are probably a tooling device to aid a supplier."

Randy, can you explain what this sentence means? Are you saying that the shape allowed the machine that made the part to "get in there" to do it, or something like that?

Dawn

Forming ribs or shapes that break up a smooth surface many times help a press shop hold tolerances, sometimes lower the tonnage to make the part, and in this case, probably make the shape a little stronger. This may have been what one particular supplier wanted to do, and may have gotten permission by way of a deviation.

We do have to be careful when looking at service part illustrations, as they are not proof that the production parts looked that way. Sometimes they are drawn from a photo that may have been a prototype part, or from supplier's literature, there are many sources the illustrators use. It just has to be close enough to not cause parts men to really doubt they are holding the correct part as they sell it. Sometimes the part changes and the catalogers don't get the art changed for several years, just because they may not even notice.

Hi Randy-
I agree cold-forming the steel will increase its strength, and after your comment I thought about it. Unless the rounded bottom had a defect, such as prone to leaking, why did they change it? It could be a manufacturing issue too, like you say, for machining purposes. In automation, a transfer device [robotic arm] or simply just human handling may have required the housing to made with the scallops for gripping purposes. Another possibilty too might be like the air cleaners - they had different vendors in order to determine which would work best. I happened to come upon that picture in Pripps' book and, seeing Mr. Fossums', God rest his soul, comment that it was original for the early 9N, I was just curious to find out. I get real anal about originality...thanks for all your valuable info.

Tim Daley(MI)

Wow, I had no idea! Thanks for the explanation!

Dawn