Sandwich question (No mayo jokes, Please)
 

Noob question: I'm installing a Setrab Series 1 oil cooler oriented with the tubes vertical, so the oil needs to flow from the bottom to the top. I have a Setrab billet sandwich plate and need to know which port is out flow to the cooler. I've looked at several diagrams for other plates but I can't find one that is Setrab specific.

I initially thought it would be the passenger side but other diagrams show the driver side.

Oil flows from the outside of the filter to the inside. You'll need to look at the sandwich plate and see how the oil moves through it

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It moves in mysterious ways. Looks like the "green dot side is the out flow?

Appears to be set up the same as the sandwich plate I sell on my website. So the green dot side is return from heat exchanger. Non green side will go to the heat exchanger inlet

Here's a detailed diagramhttps://uploads.tapatalk-cdn.com/202...240a3df59a.jpg

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so detailed








Seriously, I second-guessed myself a few times. No shame.

Let's take this to the tertiary level of guessing.

The oil comes from the engine into the plate through a hole in front of the thermostat spring which is open to the port on the green dot side. So, that port is always pressurized which means the line going to cooler is also pressurized as is the return line to the sandwich.

So, when the thermostat opens, it lets oil flow back into the sandwich plate from the cooler through the return line, which is the opposite of the diagram.

Can you explain it another way? I'm happy to be wrong.

Maybe I'm misunderstanding what you said but... The thermostat actually closes flow, not opens. The heat exchanger is always open to the motor. But with the thermostat open (cold), there is equal flow on both sides of the thermostat. So most most oil will flow past it into the filter, because it has no reason to travel through the heat exchanger first. Some will. But a good portion won't. When the thermostat gets hot it will block flow between the motor and the filter inlet, forcing the oil to flow through the heat exchanger first

Edit: oil comes from the engine into the bottom of the sandwich plate on the non-green button side. Immediately exits the sandwich plate and returns on the green button side before going into the bottom of the filter(on the outside edge). Then exits the filter through the center. When the thermostat is cold, the heat exchanger is bypassed as the oil flows past the thermostat "window"

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Oil usually flows into the cooler first, then into the filter. Therefore in practice, it's irrelevant which side is inlet and outlet to the radiator unless you want to install some sort of check valve or your radiator is meant to function in a certain flow direction.

Sandwich plates designs may vary, so you'll have to visually inspect your installed unit yourself and confirm the principles are the same, but this is how I interpret its function on my plate design.

Oil from the oil pump gets sent/pressurized on the entire annular channel from the BOTTOM-SIDE (the whole "moat" where the bypass sits). On my diagram, it will pressurize Port A (Radiator Supply), but most of the flow will be let through the bypass channel (going into the page) to the TOP-SIDE (where the oil filter usually sits). In the thermostat "cold" position, it both opens the bypass and obstructs Port B (Radiator Return). This is normal, as most thermostatic designs will allow some oil to trickle the core to keep it primed.


Once the thermostat is warmed up, simultaneously the bypass channel will be blocked and Port B will be unblocked, which means all the oil flow is getting routed through the radiator when at operating temperature.

Not that I don't completely trust you guys, but I contacted Setrab directly, by phone (since nobody seems to respond to emails).

They confirmed that oil flow is the same as both of the sandwich plates described above.

Setrab pointed out that the Series 1 34 row cooler holds 0.43 quarts of oil so no matter which way the oil goes in, there is enough oil flow so wouldn't be any air pockets anyway.

That doesn't make sense to me. Why would capacity affect air bubbles?

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If the flow rate was low enough, like with my oversized cooler, the bubbles might never clear from the top cavity. I don't think that was a real concern but better safe than sorry. I plumbed mine to flow from bottom up.

Interesting. I guess I figured if air got trapped, no amount of flow would clear it

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More tubes = less restriction.