Mechanical oil thermostat. Which one

[Taylor]

I am in the market for a mechanical oil thermostat for my car.  There are a few different ones I've seen out there and wanted some first hand reviews on them.  The ones I have seen are the sandwich type that go on the filter ($70-$120)  and the ones that go in line to the cooler ($60 for the one in most vw shops.  $ up to $200)

Which have you guys used and why?  I like the look of the in line ones but the prices are all different.   I think the one most shops sell is actually for automatic transmissions maybe?  The Mocal ones are pretty expensive along with the cantons.   Any help would be greatly appreciated.

[Zach Gomulka]

I used a Mocal sandwich thermostat. Worked well, we did port the passages a bit though. I chose it because I feel it keeps the lines as tidy as can be.

[Jesse/DVK]

Sandwich plate from Racimex. Keeps it simple and less fittings (cheaper )

[Jesse Wens]

http://www.riechertmotorentechnik.de/en/oil_cooling_adapter.htm

i got one from riechert,  the one which is build in to the oilfilter mount, it doesnt rely on pressure, it has a real thermostat for better temp control.

[Jim Ratto]

Hi Taylor, sorry I don't have an answer to your question. But I have something to ask and it might be something for you to think about....

What about using the stock bypass as your oil thermostat? What I am getting at is running one of the old RAPID COOL 90 deg blocks off top of case where stock doghouse goes, with -8 lines routed to a Setrab under the car with fans/air ducting. Then block air passage from fan ring to doghouse tunnel.

Would the air normally sent to doghouse now be forced to heads and cylniders since we've dammed the passage to the cooler duct?

And will the absence of the hot cooler in the engine compartment help keep engine compartment cooler and VE up?

With what I was dealing with on my car, I'm wondering if this would help further?

Sorry I'm off topic (again). 

[Taylor]

Not off topic  at all Jim.  I like that idea as it is cheaper.  My only concern is if I use oil a little thicker than stock it might bypass too much oil? I'll look into that. 

Now we will get off topic!  Why does everyone, including me use -8 line and fittings?  The pick up tube, oil pump orifices,   full flow cover and case oil ways are all bigger than -8.  Even if it's only .040-.050" it's still smaller.  Is flow restricted?

[Jim Ratto]

my old friend Darrell ran -10 on his ex boss' Berg 90.5 x 86

[Jeff68]

All right - hopefully I'll explain this right.  Using a smaller line won't restrict flow. In other words the same amount of oil will have to flow through the line. When using a smaller oil line you will have (should) higher oil pressure in the line. This is based on the principle of continuity of flow -
 
 Mathematically speaking: Pressure = Lbs. per square inch (psi)
To calculate pressure - Volume of oil flowing in the line (in³)/ Area of oil line (in²) = inches of pressure
Then inches of pressure (in) * density of oil (lbs per in³) = lbs per in²) or psi

The velocity (speed - in per sec) flowing in the line will also be higher given the same flow:
Flow rate = Oil velocity in oil line (in per sec) * Area of oil line (in²) = in³) per sec.

This neglects friction losses in the hose and fittings which will lower the flows, oil velocity, and oil pressure.


Feel free to correct me as it's the day after New Years.....

[Taylor]

Thanks for the break down Jeff.  So my findings are correct.  I once ran a motor on the dyno and was getting the pressure reading off the outlet line on the oil filter.  We had a pretty long oil feed line of about 4".  The pressure was pretty high at cold oil temp and it freaked me out.  We shut the motor off and moved the pressure reading to the stock location.  There the reading was what I expected to see.

So as long as I'm not using a brake line for oil feed and using the stock location for pressure readings,  I should be ok.

[drgouk]

Thanks for the break down Jeff.  So my findings are correct.  I once ran a motor on the dyno and was getting the pressure reading off the outlet line on the oil filter.  We had a pretty long oil feed line of about 4".  The pressure was pretty high at cold oil temp and it freaked me out.  We shut the motor off and moved the pressure reading to the stock location.  There the reading was what I expected to see.

So as long as I'm not using a brake line for oil feed and using the stock location for pressure readings,  I should be ok.

The reading before the filter will come back close to your main oil galley pressure as the oil gets to operating temp, If it doesn't your filter is restrictive. I normally see about a 10 psi drop across the filter at 190F oil temp on the dyno. It can be up to 40psi when its real cold.