Oil Cooler Sandwich Plate Will Not Fit With Factory Oil Warmer
 

I've had an oil cooler setup that I poached from a Saab 900 in the scrap yard laying around for years, I figured as I am mid build on the Miata I could try and put it to good use. The problem I'm running into is that the factory oil cooler, Sandwich plate and filter will not all fit onto the oil filter bolt/tube. Its just too short when I add the factory heat exchanger into the equation.

In the reading that I've done and of the pictures I've seen, people leave the factory oil warmer in place between the Mocal Sandwich plate and the block.

My question is how? What am I missing?

Car is a 90
Motor is a 94 (oil filter bolt tube is from that motor, so is the oil heat exchanger)
Sandwich Plate is your run of the mill Mocal style

I've read that the 1.6 had a shorter bolt/tube but mine is from the 1.8 so I'm not sure what I'm missing.

A picture is worth a thousand words so here you go.

Any discussion/ advice is appreciated.


Here's the general problem.
https://www.miataturbo.net/attachmen...ine=1440121069

Here's without the factory oil warmer.
https://www.miataturbo.net/attachmen...ine=1440121069

Here's the plate I'm dealing with
https://www.miataturbo.net/attachmen...ine=1440121069

And for those curious, here's the actual heat exchanger for the oil cooler. I'm a bit surprised I haven't seen people using pieces like this more here.
https://www.miataturbo.net/attachmen...ine=1440121069

Typically, an extension piece is added to the threaded tube in order to accommodate the added thickness of the sandwich plate. It's screwed on after the sandwich plate is placed over the factory heat exchanger, and secures the sandwich plate against it.

The part looks like this:

https://www.miataturbo.net/attachmen...ine=1440123344

Do you have that part? I don't see it in any of your photos.

Well, that'd certainly do it! No I do not. Hopefully I can find somewhere to order one on its own.

Thank you sir!

I always figured people ditched the warmers.

Not 100% certain about fitment of any specific part with your specific sandwich plate, but they're easy to find:

https://www.pegasusautoracing.com/pr...asp?RecID=7193

They are highly beneficial during warm-up, and not at all ineffective at cooling the oil during normal operation. I can't imagine why you'd remove it unless your cooling system was so marginal that that little extra bit of heat was pushing it over the edge.

Yea, the ones I've found so far are just a hair wide on the outside diameter. Looks like I need about a .8 OD to fit mine :vash:

I'll likely just buy a replacement sandwhich plate/sleeve nut.

As for leaving the warmer. I've read its beneficial and its part of the path for my turbo water lines so its staying. I'll likely wait on the oil cooler in the mean time. Things will be cooling off by the time I get to drive this car anyway.

I just re-read your original post. The Saab 900 used a filter with a 3/4-16 thread, whereas the Miata engines use an M20x1.5 thread. It's quite possible that you won't find an extension in M20x1.5 which will fit through the hole on your sandwich plate.


Sidebar: Are you driving the track? Even turbocharged Miatas typically don't require external oil coolers on the street. I drove mine from San Diego to Phoenix and back, across the Sonoran Desert, twice, in the depth of summer, and never had any oil temp problems with just the OEM cooler. Ditto the Badwater Basin of Death Valley.

Track Miatas need oil coolers. Street Miatas do very well with just a coolant reroute.

This car will see some track time eventually but its a good ways from that. Its mostly just something I wanted to build as "right" as possible and this oil cooler seemed like a decent idea as it was hanging around and pretty closely matches the setups I was seeing for sale.

This being my first Miata its been hard to tell between what's certain and what's internet hearsay. I don't plan on this car seeing any driving conditions to match what you mentioned so for the time being I think you're right, the car is already fitted with a coolant re route and will see a decent radiator and ducting so for now I think I'll opt out of trying to cobble the oil cooler together and throw some money at it later down the road.

Really appreciate your input on this.

I removed it because I was tired of the stupid little coolant lines that feed it failing.

--Ian

Wouldn't an external cooler with a tstat do pretty much the same thing, but take marginally longer to heat up? I like removing things from my car.

When I first built my turbo '92, I was convinced that I needed an oil cooler. I tried two different sandwich plates, and two different sizes of cooler, but found that no matter what I did, my oil never actually made it up to normal operating temperature during the course of my five mile commute to work. (This was in San Diego, where it's always between 70-80°.) On a good day, the oil would reach maybe 180°, measured at the pan.

I ended up removing it and installed a stock 1.8 exchanger. Not only did the oil come up to temperature much faster in the morning than it ever did before, the temperature never went above 220-230° even under the harshest street conditions that I exposed the car to.

I'd like to echo what Joe is saying.

If you are street driving (I would lump autoX into this category, BTW), you absolutely, positively do not need an oil cooler. The waste heat from the extra HP that your turbo makes goes almost 100% into your cooling system through the water jackets.

If you are track driving, you absolutely, positively need an oil cooler. Even if your engine only makes 80HP. The waste heat from the high RPM bearing friction goes almost 100% into your oil and does not make its way to the cooling system well enough to keep oil temperatures in check.

This is 100% from personal experience and observation on instrumented Miatas, although I suspect it applies to other vehicles as well.

Most vendors make no distinction on sources of waste heat and how they affect your fluids differently. They are more than happy to sell you stuff you don't need.

I'm wondering if I should invest in an oil cooler. My setup is pretty poopy for a daily driver keeping the A/C condenser and all. My oil temps (measured at the pan) hover around the 220°-240°F range on the highway thanks to sustained 4k RPM's on highway (6spd/4.1).

I'm going to try hood vents and a 180° thermostat first, but even the supermiata cross flow is having troubles keeping the coolant under 210° without fans kicking on whilst on highway.

Were you running a thermostat? On my car, it goes quickly up to the temperature of the thermostat and then stays around 200F with the oil cooler fan off. With the fan on, temperatures generally stay around 185 or so on the street or highway. This is in coastal FL where temps are about 80-90 degrees plus humid, but I've also taken the car to plenty of places with 100F temps as well. Sebring is generally quite hot in my experience.

You can't really run upgraded cooling stuff without thermostats if you have a dual use car. The whole point of the upgrades is to allow you to maintain good temps while beating on the car really hard. Obviously without a thermostat that cooling capacity is going to do too much work if you're cruising on the highway or puttering around town.

One other thing I've found (through painful experience) is that if you don't have alarms or other attention getting devices that trigger on high temperatures, you will not notice until it is way too late. 99.999999 percent of the time, your temps will be completely normal so you'll get out of the habit of constantly watching those gauges every couple of seconds. Then you look down and you're like "how long has my oil temperature been at 300? Oh fuck." I am actually beginning to think that CHT is probably better to measure than coolant temp, since coolant temp requires coolant to work and will display as normal if your coolant goes missing, while the CHT will tell you exactly how close you are to warping your head.

edit: Example of what I was thinking of in terms of monitoring temps.
http://thesensorconnection.com/gauge...yrometer-gauge

Forgot to mention, drove the car in freezing temps a while back with the oil cooler + thermostat + fan and it kept the oil right at thermostat temp the whole time. IMO, oil cooler doesn't hurt.

My setup is:

[plate]-}----[filter housing + temp sensor]-----[thermostat] ====== cooler
[plate]-{--(return)--------------------------------[thermostat]

Yes, Joe was running an oil stat. Oil can't come up to temp on a quick, 5-mile commute.

Dont lump auto-x too hard. At a pro solo I'll go from being just warmed up to pegging my 250°F coolant gauge and hitting 280° in the pan with just one driver, in high 80's ambient. But spraying the radiator with the tire sprayer gets it back down between drivers changes, so that little oil warmer does do quite a bit.

That is insane. What have you done to your car that you are overheating that badly during autox? Is it just the combination of constant high rpms and low speed? I quit autox in the 90s, so I've never actually autocrossed the miata.

edit: are you running the stock coolant system? Have you done the reroute?

Out of curiosity, how many drivers do you have using the same car, and how long is the car typically idling during a session?

And what does your engine cooling system look like?

Thats a prosolo so 4 runs with about 60 seconds between them and you sit idling in the staging lanes between runs.

And thats ebay rad with reroute and silicone intakes fans. Water with eyeballed 40% prestone green stuff. Coolant temp never gets high enough to boil at the pressure of the rad cap. I added ducting to the car after that day.