Oil Filter Sandwich Plate Adapter Recommendation
 

I don't need one I have a recommendation for y'all and it's simple

Cliff notes: If you get a sandwich plate adapter to mount additional sensors, get one that uses a single round O-ring to seal against the engine. Avoid purchasing one that uses a flat gasket or some kind of pseudo-engineered shape O-ring.

Here's why. This is what I purchased at first

https://www.miataturbo.net/attachmen...ine=1343267546

This is what it's sealing problems awarded me. After the car was parked in the garage for a while this is what dripped off the underside. Leaked like a sieve.

https://www.miataturbo.net/attachmen...ine=1343267546

And you know what, I knew when I took it out of the box it looked questionable. THe seal was not flat across the top - had shrinkage lines and voids from the two ribs on the opposite side - and was harder durometer than it should have been. I am sticking my fingernail in this seal and the oil filter seal and thinking, "really?" I do this sort of thing every day at work and against my instinct I installed it.

After it confirmed my suspicions that it would leak, I ditched it for a cheap Ebay unit for $26 shipped, same shape of item, but uses only a single O-ring. The advantage being that even if the supplier of this unit screws up its O-ring durometer, size, hardness etc you can fix it with a few minutes of surfing through McMaster to get a silicone or Buna O-ring.

Here is why the single O-ring sandwich plate works better: The sealing surface has to generate at least the oil system pressure (80psi) to seal and prevent a leak. Of course you want more to have a factor of safety. The clamping pressure on the seal is set by how tight you make the mounting bolt.

Comparing the width of the O-ring to the flat seal on the leaking unit, the O-ring is only about one-seventh as wide. This means it will require one-seventh the clamping force to generate an effective seal compared to trying to tighten the flat gasket style down hard enough to generate 100psi across it's entire surface.

In these pics, the good unit is on the left and the leaker is on the right.

https://www.miataturbo.net/attachmen...ine=1343267546

You can see the O-ring is much narrower than the flat rubber seal type

https://www.miataturbo.net/attachmen...ine=1343267546

I hope this helps someone avoid the mistake I made. And the mess!

Disclaimers:

I am aware the oil filter uses a flat gasket style seal. The difference is the flat gasket type seal supplied with the "leaker" sandwich plate was a low quality POS, not flat, and hard. Just avoid the whole issue by getting a sandwich plate with a single O-ring as you will always be able to "save" a single O-ring type of design and make it work.

It's true that one could just tighten the "leaker" to the point where it would not leak. But it would have to be seven times as tight as the O-ring version to do so. Why bother? Also when I tightened down the single O-ring unit, you could feel it set in place: First the O-ring compressed fully, then I could feel it go metal-on-metal as the O-ring was compressed level with it's groove, and that's when I knew to stop tightening. It's also why I will take O-rings over gaskets for liquid sealing any day of the week.

my mocal adapter is fine.

What brand is the blue one? It looks disturbingly like one that's on my parts shelf and not yet installed.

Its extremely similar to this one

Oil filter adaptor plate-Sandwich adaptor Plate -Prosport Gauges

i had a prosport one on my ms3 when i had it.
no issues with leaking except my dumbass didn't put anything on the threads for the plugs.

never leaked from the big "flat gasket" like area...

At some torque point the Prosport would be tight enough to seal. But when I was doing a little research about sandwich plates and trying to figure out which one to buy, leakage was a fairly common issue and there is one group that seems to think the only way to mount one is by using formagasket or hondaseal or some ---- like that in between the plate and the block.

So I just did a virtual shrug and bought one. When it was in my hand I could see why it would pose a risk for sealing. Any moron can make a block of aluminum work but you need to have your thinking cap on when designing seals.

All that risk can be avoided just by using one with a single O-ring.

I checked my shelf earlier this morning. I've got the Glowshift sandwich plate which was recommended here in another thread. I took it out of the package for the first time (heh) and discovered it has an O-ring.

Yay!

+1, I can't imagine skimping on such a critical part. I have never had my Mocal part leak.

I just bought a chinese adapter. It was cheap, like 8 bucks.
I torqued it to the same spec as the oil cooler, oiled the o-ring before installing, and I have zero problems.

I also clocked the whole assembly so the hoses would not be that close to the knock sensor.

Pictured are the pressure and temp sensors for my LCD gauge pack.

https://www.miataturbo.net/attachmen...ine=1343562066

Oh, I also notched the manifold support bracket to make life easier on myself during oil changes.

I think gloshift was what I went with after calling and verifying it had an O-ring. Works fine for just carrying sensors, I didn't explore any of the MoCal oil cooler items.

Does this mean a new project Adam? :drool:

I'm looking for a new sandwich plate myself, been debating on which one to get

Not much of a project. I've just wanted to replace my oil feed / oil pressure sensor / brass tee abortion with something better. Something stronger. A little plate like this seemed ideal. I think Joe Perez suggested the Glowshift. That was enough for me.

do u guys have something like this for bp's? i rather like it, adds some 1/8" npt ports and keeps the number of connections down to just the hose fittings. (it replaces the screw-on oil filter piece).

https://www.miataturbo.net/attachmen...ine=1343618754

There are/were remote oil filter kits that had a piece like that. An oil cooler integrated in to the system with another hose. I ran one on my ITA Miata - think it came from Moss Motors way back.

Yeah, the ones with the "little sticks" or legs holding the center section to the outer scare me. It's $80 bucks, save the money somewhere else.

Widmer who owns Endyne claims the flush-nut thingies inside them fail, which is pretty scary. He also builds 10k RPM Honda engines.

Trey, the supports extending from the center to the edge in my $8 adapter plate are beefy, going down for the entire depth. I saw no reason to even suspect a structural failure. Looks solid.

I just replaced the o-ring on it during the engine rebuild to be on the safe side, that's all.
I mean, if a hand tightened oil filter can cope with all the pressure the pump can throw at it, why can't an adapter plate, held in place with a huge nut and torqued down with a tool, handle that?

This was my exact line of thinking when I purchased the first sandwich plate (the blue one with the flattish hybrid gasket). How could it not work?

In my case it didn't work because 1) It was not a primo product and 2) I could not get it tight enough to overcome the hard durometer and lack of flatness of the gasket-style O-ring it used. I'm not a big fan of using a lot of force where it shouldn't be needed... well at least not on my cars.

All I learned from this was something I knew a long time ago that for fluid sealing it is much harder to screw up or mis-engineer an O-ring connection and even when it is screwed up it's an easy fix.

Sammich plate related question:

I recently picked up an oil cooler and will be running it from a sandwich plate. I don't understand how the cooler will see any flow when both the feed and return attach to the plate at the same general location (the outer ring for lack of a better description), as shown in both plates in the first post. It seems to me that there would be no pressure differential and therefore no flow. Or do I have that all wrong and it actually works? Or are there specific plates for coolers, which are different from the type that are used for sensors, and feed from the center and return to the ring?

There are different plates for coolers.