two oil filters question

[Pantdino]

The 1964 Fiat Abarth replica vintage racer I recently bought uses a spin-on filter on top of an adapter. Lines from that adapter lead to a second canister-type filter and, past that, to an oil cooler.

Even when the car has only been shut off for a minute or so, when you restart it 2-3 seconds pass before the engine has oil pressure again. The canister-type filter housing is empty, but I have elements for it.

My take on it is that the empty canister is a big dead space that the pump has to refill each time the engine is restarted.

I'm thinking that even if I put a filter element in the canister I will still have a lot of air / dead space there. I want to keep the remote canister because that's how cars of that era were equipped and it looks correct.

I'm thinking I should do something that fills the dead space in the canister and allows the oil to shunt underneath it from input to outflow port.

Any advice is welcome

Jim

 

[Gary Allan]

Any chance of an image or two of the setup? The way I'm reading it is a sandwich adapter of some type that goes to a cooler that has an intermediate canister filter in there.

 

[slalom44]

It sounds like you have a bypass filter setup. I agreee with your diagnosis, and like Gary said, pictures would be nice. Here are a few suggestions:

• You could install a check valve to the second canister. That would prevent oil from draining back out of it.
• Install a small prelube pump from your oil drain plug port to the filter adapter. With a toggle switch under your dash, you could get full oil pressure every time you start your engine. ShurFlo sells a pump with a built-in check valve that I have been using for over 5 years without any problems.

 

[Pantdino]

Originally Posted By: slalom44
It sounds like you have a bypass filter setup. I agreee with your diagnosis, and like Gary said, pictures would be nice. Here are a few suggestions:

• You could install a check valve to the second canister. That would prevent oil from draining back out of it.
• Install a small prelube pump from your oil drain plug port to the filter adapter. With a toggle switch under your dash, you could get full oil pressure every time you start your engine. ShurFlo sells a pump with a built-in check valve that I have been using for over 5 years without any problems.

What is a bypass filter and how does it differ from a remotely located filter?

There is a sandwich adapter between the block and screw-on filter with input and output lines that run to the canister filter base. Some of these have a thermostat, so oil is not sent to the cooler unless it is hot. From the filter base the lines run to the oil cooler.

I'll post some photos when I can.

 

[Gary Allan]

Bypass filters were the first filters ever installed on internal combustion engines. They typically tapped into the pressure port and took a small fraction of the total pump output and filtered it through dense media (sometimes shredded newspaper) in a "trickle down" peculating effect ..more or less like your septic system "ground filters" your sewerage minus the digestive process.

This additional filter is/was probably to keep the cooler clean since it (probably, my speculation) received unfiltered oil when active. It may very well have a bi-metal flat spring in there that covers a cooler bypass port when the oil is cold.

That cartridge filter may NOT be a bypass(like) filter. It depends on how they set up the thermal bypass mechanism. Some, like our obsolete (but more contemporary) Ford products, used a pressure regulating poppet valve (a spring holding a ball on a seat) to regulate cooler flow. The theory being that above a certain spec'd viscosity ..the oil was cooler ..and force the low tension sprung ball off of it's seat ..allowing uncooled oil flow. As the oil heated excessively, the viscosity would drop ..the ball would seat ..and flow would be allowed to the radiator cooler up front of the cooling radiator. It was later abandoned for a more compact laminar sandwich coolantil heat exchanger. This way it basically used the cooling system to regulate everything.

 

[Pantdino]

I opened up the remote filter canister. The flow into it is circumferential from the bottom. The outflow is thru the full length of the central standpipe, which has holes in it. The filter cartidge is closed at top and bottom. There are small holes on the inside and outside surfaces. The filter medium appears to be a loose white material completely filling the element space, not a zigzag of sheet media.

The seal is created by rubber flange gaskets that seal the cartidge above and below on the perforated standpipe. There is considerable space (5-10mm) above and below the cartridge in the canister. There is only 5-6mm difference between the ID of the cartidge and the OD of the standpipe -- same for the difference between the outside diameter of the cartidge and ID of the canister. So about 2-3mmm space between the cartidge and the canister structures on the inside and outside.

It looks to me like the previous owner simply forgot to replace the cartidge, which will retain oil very well once soaked in it and not bleed down / empty with sitting. If I leave off the rubber sealing rings the oil will flow above and below the cartidge itself and should not create resistance to flow.

I'm awaiting the delivery of some Baldwin filters to my local store, at which point I'll change the screw-on filter and oil and fire the car up. I'm thinking I'll presoak the cartridge in the oil to fill it to eliminate the dead space that will have to be filled as the canister fills the first time.

Does that make sense?

 

[Gary Allan]

Sounds like a shredded newspaper filter (cellulose).

Sounds like you have a sound plan.

 

[Pantdino]

Some follow-up:

I tried soaking the filter cartridge in oil but it just sort of floated, so I put it in the canister and started the engine.
On startup the oil pressure came up after a much shorter time than before.
On shutdown the pressure used to instantly drop to zero-- now it slowly sinks down and upon restart instantly zips up again.

After running the engine the cartridge was fully soaked and no longer floats.

I think the problem is solved

Thanks, Everytone!