Batwing-eight

Replacing a bypass oil filter with full-flow.......?

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Has anyone attempted to modify a mid-'30s engine originally equipped with a bypass oil filter, to become full-flow by modifying the block to support either a  period-correct canister with replaceable cartridge or possibly even a modern spin-on?  Another possibility might be the combination full-flow/bypass system utilizing a "dual-range" spin-on filter.

 

For either option, how was the block modified? Obviously, the oil path within the block would have to be altered, at least slightly.

 

Vintage bypass oil is highly filtered, but doesn't go directly to the moving parts.  A full-flow system would seem to suggest all moving parts receive oil having at least some filtration. 

 

Encouragements and caveats welcomed. Thanks, Bill.

 

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Posted (edited)

Some previous discussions:

and so on. Do you still want to change the filter?

 

 

Edited by Spinneyhill (see edit history)

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For the average use of a 1930's collector car I wouldn't bother with an oil filter. Although mine are newer, I change the oil in my cars every year. They range from 500 miles to, maybe, 1200 between changes. As my Wife will willingly tell anyone, I make sure I drive a minimum of 10-15 miles when I start a car. Even if I am moving it from one side of the garage to the other.

 

And looking out my window today the cold rain is doing a great job of washing particles out of the air.

Bernie

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Posted (edited)

I am not sure I am the question asked . But on the 1931 Reo Royale 8 cylinder engines the owners have made an adapter to take a modern oil filter . Then you cut a round hole in the original pancake oil filter remove the steel wool like material . Then slip it over the modern oil filter . 

 

Edited by Mark Gregory (see edit history)

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Posted (edited)

In some of the early" bypass" oil filtration systems only when there is an excess of oil pressure does some of the oil get to go through the filter.

 

And as far as early bypass filters being better at filter smaller particles than a modern spin-on filter, I've cut open many Purolator and other brand canister filters to convert them to modern spin-on filters hidden inside. Just painted one Friday for a customer. And if you were to cut open those 1920's and early 30's canisters you'd find that the filter medium is just layers of cotton cheese cloth wrapped around the perforated center core tube and tied with string. 

 

And those early bypass systems don't get as much oil flow as some might think. That's why the decals on them say to change the filter either 8000, or 10,000 miles, depending on brand. At lower engine speeds that do not produce enough oil pressure to open the pressure regulator valve, no oil goes through the filter. All the output is going directly to the bearings and then back to the oil sump to go through the pump again.

 

And if you modify the pressure regulator spring to increase oil pressure, then even less oil gets to go through the filter until that higher pressure is reached. So while worrying about why old engines don't use high oil, and boosting the oil pressure like later engines, solving a non-problem  can cause a problem by lessening of filtration.

 

I did modify one 1932 system to be full flow, but it takes away from the originality to tee in feed and return line oil lines off the oil pump output line out through the side of the engine base to a spin-on filter.  A trade-off the customer wanted so as to have all the oil pump output go through a modern spin-on filter before going to any of the bearings.  I much prefer a modern spin-on hidden in the bypass filter housing and change the oil more often.

 

Paul

Edited by PFitz (see edit history)
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Posted (edited)

All filters were bypass filters until the introduction of hydraulic lifters. Hydraulic lifters can be bunged up by a small piece of dirt or sludge. I believe full flow filters were developed for hydraulic lifter engines.

 

Any filter is better than no filter at all. A bypass filter cleans all the oil, just not all at once. Compare it to a pool filter that takes in only a small amount of water, but in a day or 2 will make a murky pool sparkling clean.

 

One interesting comment was from a Studebaker expert. He said he had disassembled and rebuilt hundreds of Studebaker V8s. There was no measurable difference in wear or cleanliness between full flow and bypass filter motors. When the Stude V8 was introduced in 1951 it had a bypass filter - and solid lifters. Even though the supposedly superior full flow filters had been available for several years, Studebaker engineers chose the bypass type. They did not adapt the full flow filter until the early sixties. This expert said he would not pay a premium for a full flow filter engine even though many people do.

 

Short answer, keep the bypass filter, make sure you use the correct type (fine) filter element and change it according to the manufacturer's recommendation.  With today's laser electronic thermometers it would be a simple matter to keep tabs on the oil filter temperature,  and replace it when it starts to run cool. This is a sign that it is plugged up and not flowing oil.

 

Use good quality detergent oil and change it regularly. 10W30 or whatever the manufacturer recommends. Do not think you have to run thick oil or non detergent, that is a myth.

Edited by Rusty_OToole (see edit history)

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A good friend has an older, otherwise excellent restoration of a post-1932 Pierce V-12.  When Pierce adopted hydraulic lifters in 1933, the Company began using full-flow filters, WHICH HAD 1/2-INCH SUPPLY AND RETURN LINES. This car was restored with 1/4-inch lines suitable for bypass filters but not capable of the volume needed for a full-flow filter, resulting (when the previous owner acquired it) in 10 psi oil pressure.  The previous owner bypassed with a modern 1/2-inch hose, giving 50 psi--saving the engine.  Fortuitously, before that the car was strictly a show car rolling on and off trailers, so apparently no damage was done.  The point of this story is to recommend thorough consideration of the size of lines in and out of a full-flow filter if you are planning to use one where a bypass filter was factory equipment.

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I like PFitz answer - incredibly skilled fellow too.  

 

My best advice is to either put it back to original or adapt a modern filter into an original case, but all said and done the mileage  most 30's cars get over time and road conditions they are exposed to ... = not sure a herculean effort is really needed.  Also, a significant number of brass, nickle, 20's, 30's, and 40's cars do not even have oil filters to begin with. 

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Keep the original filter setup. Use the correct filter element. Change oil and filter regularly.  There is nothing to gain from changing to full flow.

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Thanks to all who responded! Re-routing the oil pump line to the outside of the motor to attach a full-flow filter and returning it to the inside will require two new holes in the block as well as creating some challenges in the plumbing and routing of those lines inside the block...... so for now I've decided to stick with the original bypass system. 

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