Nissan 370Z Forum - View Single Post - Mishimoto Thermostatic Sandwich Plate, Gold

wstar · 05-02-2013, 07:02 AM

I hadn't seen this unit before, and I'm a fan of the fact that it's easy to swap to other temps, but...

I had to double-check their site after I read your description, and sure enough it says "The built-in thermostat prevents oil flow to the cooler until the engine oil reaches activating temperature". This is not the same way the normal Mocal thermostatic sandwich plates (used by most of the vendor kits and the DIY types) work. The way those work is they leave both pathways open when cold, and then as you cross the thermo threshold they gradually close off the bypass, forcing all oil through the cooler at higher temps (it's about a 10 degree range while it slowly closes it off, but that's a minor point).

Supposedly there are advantages to leaving both paths open under cold conditions: the oil still mostly takes the bypass as the "path of least resistance", so it still doesn't overchill the oil (unless temps are extremely cold and you're on the highway, in which case you need a blockoff plate), but the small amount of flow to the cooler that *is* happening while the oil's warming up also gradually warms up the lines and the cooler itself.

If this unit really operates as described, there could be a thermal shock if it suddenly sends 180F oil down to the cooler when the cooler's still dead cold.

Of course, there's also a good chance that the Mishimoto one works the same as the Mocal one, but that lots of people just don't get how it operates, including whoever wrote the text on their store. You might confirm it by physically looking at the passageways in the unit. It should be obvious: the "bypass" passage would have the thermostat, and the passageway that leads to the cooler lines wouldn't have any kind of valve in the way.

05-02-2013, 07:02 AM	#4 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	I hadn't seen this unit before, and I'm a fan of the fact that it's easy to swap to other temps, but... I had to double-check their site after I read your description, and sure enough it says "The built-in thermostat prevents oil flow to the cooler until the engine oil reaches activating temperature". This is not the same way the normal Mocal thermostatic sandwich plates (used by most of the vendor kits and the DIY types) work. The way those work is they leave both pathways open when cold, and then as you cross the thermo threshold they gradually close off the bypass, forcing all oil through the cooler at higher temps (it's about a 10 degree range while it slowly closes it off, but that's a minor point). Supposedly there are advantages to leaving both paths open under cold conditions: the oil still mostly takes the bypass as the "path of least resistance", so it still doesn't overchill the oil (unless temps are extremely cold and you're on the highway, in which case you need a blockoff plate), but the small amount of flow to the cooler that is happening while the oil's warming up also gradually warms up the lines and the cooler itself. If this unit really operates as described, there could be a thermal shock if it suddenly sends 180F oil down to the cooler when the cooler's still dead cold. Of course, there's also a good chance that the Mishimoto one works the same as the Mocal one, but that lots of people just don't get how it operates, including whoever wrote the text on their store. You might confirm it by physically looking at the passageways in the unit. It should be obvious: the "bypass" passage would have the thermostat, and the passageway that leads to the cooler lines wouldn't have any kind of valve in the way. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 05-02-2013 at 07:04 AM.