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Aftermarket Oil Filter on Pre-War Car


George Cole
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I'm putting 2 Cole V8s together with the intention of them being reliable drivers/touring cars.  They have external oil pumps with a suction line from the oil pan and a pressure line back into the engine.  The only filtration is a brass screen in the base of the oil pan.  Cleaning it requires dropping the pan.  I've pretty much convinced myself that I'm going to put an aftermarket oil filter in-line with the pump output.  I suspect others have done something similar.  Comments?  Pictures?  Details?

Thanks, George

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I kind of have a split opinion on oil filters. If the car came with one or it was available as an option or dealer-installed, sure, install it. But on an older car not designed for a filter, well, I'm not convinced it will do any good and can make some mischief. Oils of the 1920s were vastly different than what we have today and the way we drive old cars isn't particularly demanding. No more dirt roads, for example. Today's "detergent" oils aren't cleaning anything like the myth suggests; "detergent" simply means those oils hold particles in suspension better than non-detergent oils, which is why old cars needed big oil pans and why cleaning them out periodically were required. The dirt tended to settle in the pan, which was by design. Add in the fact that there's no more lead in the gas and that most of the "dirt" that gets picked up by the oil is due to the combustion process and not grit getting sucked into the engine, and I start to question the need for filtration where none existed originally.

 

Now with that said, I will admit that all my old cars do have oil filters on them, from the 1929 Cadillac to the 1956 Chrysler (and beyond, of course). The 1929 Cadillac had a modern spin-on filter setup on it when I bought it that was plumbed in using rubber hoses connected to the oil pressure gauge. It looked like crap, but I guess it worked. I replaced it using a reproduction canister with a spin-on filter inside that looked correct and re-plumbed it with hard lines. HOWEVER, I apparently removed some restriction in the system because my oil pressure dropped to 0. I spent a few weeks doing some reconfiguring and changed a few fittings, and eventually the oil pressure came back, but that was scary. If the filter wasn't already there I would not have bothered with the project. I just hated those rubber lines and that modern filter just hanging there limp.

 

You can sort of see the old filter in the lower left corner of this photo (click to enlarge):

DSCN3015.thumb.JPG.76bc5f269696e8b59b9b21b7189f79a2.JPG

 

Here's what I did to replace it:

IMG_0874.jpg.6531ee11802dd41d7732b844df24b9ab.jpg  IMG_0871.jpg.05c9299b536f21d34eeea02454b93b41.jpg  IMG_0872.jpg.03b26b531e6c024da48260b50ab82165.jpg

 

I've changed that filter once in the Cadillac since making the change-over. My '41 Buick has a 1941 drop-in style cartridge in a can, and I think I've changed that once during my 10,000 miles of ownership. I also changed the one on my 1935 Lincoln to a modern spin-on in a vintage canister style with no ill effects, but the filter was already there from new. It's worth noting that these are all partial flow filters so only some of the oil circulating through the engine is going through the filter--they really don't do much and there's still plenty of "dirty" oil running through the bearings and rings at any given moment, filter or no filter. 

 

So I guess oil filters seem be a good idea, but they can also cause mischief and add complexity where it's not needed. Maybe you're adding resistance that inhibits flow to the bearings, or maybe you're removing a restriction that needs to be there for the system to operate correctly, like me. If none of my cars had filters, I would not install them. I drive my oldest cars more than most but if I put 3000 miles a year on any one of them, that's a lot. I'm actually not convinced that a filter is cleaning the oil any better than just changing the oil every November before I store them for the winter, and today's oils are so much better than whatever they were using when your car was new.

 

My advice is to leave well enough alone and trust the guys who built it. Simply change your oil every year before you store it to get the contaminants out. We tend to over-think the preservation of our old cars and try to do every last little thing to keep them healthy, but I think this is waaaaay out on the narrow end of the diminishing returns curve. Even if you're putting thousands of miles a year on it, the engine will still outlast us all, filter or no filter. This isn't a failure vector.

 

Hope this helps.

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I think I'd be more concerned to put an air filter on the car, if that is doable. The dust and grit that got sucked in with the air was far more damaging than anything else. If you change the oil regularly and don't let it get terribly dirty I doubt an oil filter will do much.

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It's a myth that bypass or partial flow filters don't filter all the oil. They do, just not all at once. Compare to a pool filter that takes only a small amount of water at a time, but over a few days will make a murky pool sparkling clean. Bypass filters have the advantage of filtering out much smaller particles of dirt than a full flow. Bypass filters were the only kind for years, they were standard equipment on luxury cars and optional on cheaper cars. Full flow filters came in about the same time as hydraulic lifters and I think there was a connection, as hydraulic lifters can be jammed up by a small particle of dirt.

 

I can only recall two or three engines that were offered with no filter, a bypass filter or a full flow. That is the Chevrolet six, 1937 - 1962. They came originally with no filter unless you bought the optional extra bypass filter but the last ones in the late 50s up to 62, offered a full flow.

 

Chrysler flathead sixes had a bypass filter up to the late forties then changed to a full flow. Studebaker V8 had a bypass from 1951 to around 1960, then got a full flow.

 

The point is, any filter is better than no filter. You could study the routing of oil lines on the above engines and see how the factories did it. Whatever kind of filter you use, you need some kind of bypass in case the filter gets completely clogged or plugged up.

Edited by Rusty_OToole (see edit history)
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7 hours ago, JV Puleo said:

I think I'd be more concerned to put an air filter on the car, if that is doable. The dust and grit that got sucked in with the air was far more damaging than anything else. If you change the oil regularly and don't let it get terribly dirty I doubt an oil filter will do much.

Yes, I agree.  I also intend to add air filters although clearance is tight with the updraft carb intakes sitting low between the cylinder banks and zero clearance between the intake and carb body (see below image).

 

I have an owner's manual for the 1920, as well as one for a 1918.  They both state that the oil should be changed every 1500-2000 miles.  They go on to say that at 5000 miles or every 6 months, the oil should be replaced with a 3-to-1 kerosene/oil mix, the engine should be run for 30 seconds, and the oil pan should be removed and the screen thoroughly cleaned.  Even though oil filters hadn't been invented when these cars were built over 100 years ago, the designers were obviously aware that oil does need to somehow be cleaned and filtered, as well as being frequently replaced.

 

My intention is to install a filter in parallel with the oil pump output line to the engine.  That location is before the pressure relief valve, which should not adversely affect engine oil pressure or restrict output from the pump.  

Stromberg.jpg

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My Pontiac came with a partial flow oil filter.  I had never seen my Grandfather change the filter from 1946 until 1959 when I started driving it.  Filters were still available then so I started changing the filter at the specified miles.  What I noticed was that the filter was hot for about 500 miles and then it did not get hot any more.  That suggested that the filter was plugged full and no oil was circulating through the filter.  By that time replacement filters were hard to find.  I bought several to have if I ever wanted to restore the car and wanted it to look right, The next 300,000+ miles i drove it without a filter.  I have had the pan off four times between 99,000 and 500,000 miles.  Each time there was sludge in the oil pan but I still got over 160,000 miles between engine overhauls.  I did install one of Bob's proper looking canisters with a spin on filter inside on my last overhaul.

I think if it didn't come with a filter it isn't worth the bother to adapt one for the amount of miles you/we expect to put on these cars today.

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10 hours ago, George Cole said:

Yes, I agree.  I also intend to add air filters although clearance is tight with the updraft carb intakes sitting low between the cylinder banks and zero clearance between the intake and carb body (see below image).

 

I have an owner's manual for the 1920, as well as one for a 1918.  They both state that the oil should be changed every 1500-2000 miles.  They go on to say that at 5000 miles or every 6 months, the oil should be replaced with a 3-to-1 kerosene/oil mix, the engine should be run for 30 seconds, and the oil pan should be removed and the screen thoroughly cleaned.  Even though oil filters hadn't been invented when these cars were built over 100 years ago, the designers were obviously aware that oil does need to somehow be cleaned and filtered, as well as being frequently replaced.

 

My intention is to install a filter in parallel with the oil pump output line to the engine.  That location is before the pressure relief valve, which should not adversely affect engine oil pressure or restrict output from the pump.  

Stromberg.jpg

 

Wow! That's quite a carburetor

 

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Bypass oil filters are fine, but they need to be restricted down, way down, even on new engines. In 1930, Pierce offered an aftermarket oil filter through the factory. It came with brackets, a canister, oil lines, and fitting for the engine block. One of the fittings was restricted down to .08 or just under. With today’s modern oils, changing it every thousand miles if you don’t have a filter is fine. On our last tour, we did 1800 miles on a Model J in under two weeks. I did an oil drop at 900 miles, even though 2500 would be fine, I like to check for metal in the drain bucket. Also, when rebuilding an engine today, installing magnets in the  oil pan works wonders, and is probably half as good as using a filter. 

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