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1920 Maxwell oiling system


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newly rebuilt Maxwell motor recently seized up on a drive and, after dropping the pan, I discovered no pickup tube to the oil pump. From what I have read, there was some sort of plunger set up in the pan, also. Looking at the bottom edge of the block there appears to be a triangular area with two threaded holes which, I assume, were for the flange of this tube. Is anyone familiar with the oiling system of these cars? Your help and advice would be greatly appreciated.

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newly rebuilt Maxwell motor recently seized up on a drive and, after dropping the pan, I discovered no pickup tube to the oil pump. From what I have read, there was some sort of plunger set up in the pan, also. Looking at the bottom edge of the block there appears to be a triangular area with two threaded holes which, I assume, were for the flange of this tube. Is anyone familiar with the oiling system of these cars? Your help and advice would be greatly appreciated.

I didn't reply to this when you first posted because my experience is with 1917 and earlier Maxwells and I wasn't sure how similar they were. While going through eBay tonight I got this photo from a 1920 Maxwell owners manual and compared it to my 1917 manual. except for some minor changes they are almost identical. After going back over your post your talk of "triangular area with two threaded holes" worries me. In both my 1917 and the 1920 picture no pickup is used. The flange you talk of is the mounting for the oil pump and integral screen which sucks oil from the bottom of the pan. To me it appears as if your motor was assembled without the oil pump and oil pump plunger.post-33891-143142695734_thumb.jpg

Howard Dennis

post-33891-14314269573_thumb.jpg

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Thank you for taking the time to write. The information you stated is correct. I never had the oil pump or the related parts so I never even knew they were missing! The motor ran for a while (probably on just the oil dippers) then seized. This is pretty sad for someone who considers himself a pretty decent mechanic! I have looked into the possibility of using a later 4 cyl. Chrysler oil pump (which I can obtain) but these are gear driven. My system drives the oil pump shaft from an eccentric lobe on the camshaft. If you happen to have the pump and the related parts or know where I might find them, I would be very grateful and would gladly pay your price for these items.

gary

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  • 1 month later...

Howard,

I am hoping you can help me. I am working on that '17 motor which CHris dropped off to me and I noticed that there is NO oil pump plunger which, from what I can tell, must be some kind of rod that threads into the plunger in the block and pushes up and down in the pan oil pump chamber. I am pretty much in the dark about this piece since it is missing. What I can describe is this; there is a "piston" in a chamber running off the crank(?) which travels up and down but does not travel past the edge of the block. My oil pan has a round tube chamber which looks like it is made for some sort of plunger. In the "tube" at the bottom is a check valve using a ball bearing. Also, above the check valve is some sort of limiter pin extending from the side of the "tube". I understand that you have begun work on a similar engine. I would be extremely grateful if you would forward me a picture of this rod/plunger, perhaps with dimensions. If you knew where I might find one, even better.

Thank you much!

gary

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Gary, I'm afraid I can't help on this one. My car came to me with a totally rebuilt engine, one reason I decided to tackle such a basket case. I've never had one apart except the rough parts engine in a photo above that had the pan and oil pump knocked off in an accident. It came to me missing those parts and I only have what is in my assembled running engine with no spares. I hope someone on here will chime in and be able to help you.

Howard Dennis

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  • 2 weeks later...

I have solved my own oil pump problem. I found that the oil pump plunger which pumps the oil from a tube in the oil pan thru a network of tubes to the dipper galleys is exactly the same size as a 12 mm socket. I measured the "throw" of the plunger movement and tack welded the correct length of 10-14 hardened rod to the socket top and then threaded the top portion of the rod into the oil pump piston in the block. This piston runs off an eccentric on the car and is governed by a heavy spring. I used Lock_tite and also a lock nut on the rod. I tested the movement and it works great. ALso, I noticed that there is a removable plug on the side of the pan to prime this set up. By 1922 Maxwell did away with this system in favor of a much more reliable geared oil pump.

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  • 6 years later...

Gary,

Maybe you can help me out now. Checking my 1917 engine's valve chamber and am curious if you know anything about how tappets and valve stems get lubrication?  There are no tubes nor can I find any way valve chamber is supplied with oil nor how it would return  to oil pan?

 

Howard Dennis

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Somewhere either about Maxwells or Model T's I read that they're designed to suck oil vapor through the tappett clearances via intake vacuum through the valve guide clearances.  I had wondered the same thing.  Apparently Model Ts can build up oil on long runs and overfill the valve box, and it will start smoking like crazy.  They later added a 3/16 drain hole.  Not sure how Maxwell gets away with it.

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Thanks,

That makes a lot of sense. When I got no response on this question I went back to the garage and rechecked my valve chamber to look for drain holes and found none. I then checked the tappet travel wondering if they acted as pumps and brought the oil that was splashed on them from the crankcase up into the valve chamber. That was when I noticed that although I assumed the valve chamber was dry from lack of oil I now believe the oil has drained back past the tappets since the last time (months) I ran it as I noticed that the tappets were well lubricated in their bores when I moved them after their long winter's nap.  If you ever run across your source of this information please post it here so I can save it to my files.

 

Howard Dennis

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maxwellfox, 

Appreciate the help, makes me feel a lot better about my engines oil system. Seems like these oldtimers followed the KISS strategy of design.

 

Howard Dennis 

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The engines not working real hard (low compression, low speed) I feel helps the whole situation a ton.  When I had the valve cover off I squirted some oil around all the contact surfaces anyways just to be safe.  Im currently hand wringing over not pulling the oil pump to verify its working when I had the pan off.  But it looked more entangled than I wanted to get into at the time.

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