Re: [Amc-list] 1956. Oil Filter Trivia

[farna@xxxxxxx]

About the filter -- it's worse than just dirty oil running back into the engine. It's a PARTIAL FLOW filter. Only 20% at the most gets filtered at any one time. The filter is plumbed into the main oil galley just like a pressure sensor owuld be. Only excess pressure goes through the filter. It's a "better than nothing" filter, that's it. 

The 195.6 is derived directly from the 1941 172.6 introduced in the first unit body Nash, the 600. That means it's really late 30s technology. It wasn't cutting edge at the time, just par for the course as far as engine design. It was an economy engine from the start! The 600 designation came from the fact that a very careful driver (well, professional economy drivers) could squeeze 30 mpg from the car with a 20 gallon tank. So theoretically it was possible to get 600 miles from a tank of gas. Note: "theoretically possible" doesn't mean Joe Blow could, but they'd get in the mid 20s easy enough -- not enough power to get much worse! 

The original engine (all engines in the 30s through early 50s) came with an oil pan cleaning interval. They ran non-detergent oil that allowed all dirt/trash to settle in the pan when the engine was stopped. Over time a sludge built up in the bottom of the pan, so it had ot be removed and cleaned every so many miles or time interval. The sludge in the bottom of the pan was better than having it float around in the oil and get back in the bearings. For low speed engines it worked well. This is why older cars were designed with no permanent crossmember under the engine -- so it was easy to remove and clean the pan.

Detergent keeps trash suspended in the oil so that the filter will catch it. This eliminates the need to remove and clean the pan but demands a filter in the system, preferably a full flow filter. Only aluminum and 1965 (and some late production 1964) 195.6 engines have a full flow filter. The aluminum model oil pump won't fit the cast iron block. If the engine has an oil filter on the oil pump it's full flow. The ones on the head are the partial flow. Unfortunately there isn't enough room in the 58-63 American to fit a full flow even if you find one. The only change is the pump cover, by the way. 

The oil filters for the partial flow (head mount) filter are still available. The fitting is different than any other car, so go to NAPA, Car Quest, or a similar store that sells a lot of industrial service parts. The filter is still used on many industrial engines such as the refer units on large trailers. Autozone and such won't have them on the shelf, NAPA and Car Quest might if it's a big store or the store services industrial users. 

--
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)
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