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Fri Feb 10, 2012 7:42 pm

from my STF build thread:

I wanted my oil temperature sensor to read accurately so I installed it into the full flow filter housing. This provides a direct reading of the oil as it returns to the case and into the bearings. The sensor would block part of the flow passage because the adapter didn't have enough material to tap. It would install too deep. To remedy this, I TIG welded a boss, faced off, drilled, and tapped the housing to provide a thicker area to thread the M10x1.0 sensor in. The inside is ported and polished for smooth flow. I also blue printed my Schadeck 26mm pump, as per the Bill Fisher manual.

Fri Feb 10, 2012 7:46 pm

http://vwparts.aircooled.net/Adapter-Bushing-1-2-NPT-to-1-8-NPT-p/adapter-bushing.htm

is another outstanding location, most do not know about.

Sat Feb 11, 2012 12:36 am

I made this up, works like a champ.

Sat Feb 11, 2012 1:07 am

[email protected] wrote: http://vwparts.aircooled.net/Adapter-Bushing-1-2-NPT-to-1-8-NPT-p/adapter-bushing.htm

is another outstanding location, most do not know about.

Does this include the tap and/or sender as well??

Sat Feb 11, 2012 6:03 am

Hotrodvw wrote:

Does this include the tap and/or sender as well??

At $9.95 - I'm sure you'll only receive the adapter fitting. The sending unit alone is $33.

Fri Jan 18, 2013 5:17 am

How accurate are the drain plug sensors? I'm getting some gauges and wondering if that's a good way to go... Obviously the drain plug is in constant contact with oil in the case.

Fri Jan 18, 2013 7:34 am

aryue wrote: Hotrodvw wrote:

Does this include the tap and/or sender as well??

At $9.95 - I'm sure you'll only receive the adapter fitting. The sending unit alone is $33.

Fortunately, you can buy that same bushing for about three dollars at any hard ware store.

Fri Jan 18, 2013 7:37 am

fory wrote: How accurate are the drain plug sensors? I'm getting some gauges and wondering if that's a good way to go... Obviously the drain plug is in constant contact with oil in the case.

So long as your engine is running, there is oil flowing past the sensor. I think it's a great location myself. I have a couple left.

Fri Jan 18, 2013 4:18 pm

I have mine in the return line from the cooler in a seperate tee piece, i have been measuring the temp of the case and found that it is always hotter than the oil due to heat soak from the barrels and other parts of the engine so if the sender is installed in the case the temp reading in my opinion will not be acurate, you want to know if your oil cooler is actually doing anything, it would be ideal to have two senders so you can get the detla t across the cooler, you could use a rotory switch to change between the two senders, i also have a 10" fan on my cooler that was actuated by the switch supplied but was not very consistant, i installed on of these that allow's you to set the turn on and turn of point of the fan and have a alarm if it goes over your preset temp http://www.ebay.com.au/itm/BMW-ENGINE-ALARM-1-3-5-...2a26373a48 , also my cooler was supplied with the fan drawing air through the cooler, i turned the fan over and run it backwards thus pushing air through the cooler, this was also a improvement, next move is to fabricate a small scoop to to direct air onto the cooler directly from under the car, i bought a infrered heat gun and this is a good investmtent so you can check the acuracy of your system, my autometer oil temp gauge was out conciderably and the monitor is out by 4 degrees on the high side.

Fri Jan 18, 2013 9:46 pm

[email protected] wrote: http://vwparts.aircooled.net/Adapter-Bushing-1-2-NPT-to-1-8-NPT-p/adapter-bushing.htm

is another outstanding location, most do not know about.

That is where I put mine.... I bought the bushing from you.

Sat Jan 19, 2013 9:47 am

Jimmy111 wrote: That is really a bad place for it. The only time it will work is when your relief valve leaks. Then what is the point. The motor just overheats anyways :D
There is absoultly zero circulation of oil there.

Never thought of that...seems legit though, anyone else have any thoughts on this?

Ben

Sat Jan 19, 2013 11:25 am

There's no o-ring sealing the piston to the case. There will -always- be a small amount of leakage there. Whether or not it's enough to give the sensor an accurate reading is up for discussion. I believe it would be plenty.

Sat Jan 19, 2013 11:33 am

Alpha_Maverick wrote: There's no o-ring sealing the piston to the case. There will -always- be a small amount of leakage there. Whether or not it's enough to give the sensor an accurate reading is up for discussion. I believe it would be plenty.

Correct, we're reading temperature, not pressure. A leak would effect pressure though.

Sat Jan 19, 2013 2:35 pm

You guys are talking about the relief plug sensor? There is no flow whatsoever past that - if it ever does read the same as the oil temperature, it is going to lag far behind it when it changes. It's probably going to get a liittle cooling air and read low anyway.

To the guys that have used the pickup adapter John mentioned (seems Aircooled read ob Hoover, too) how far does the sensor extend into the oil?

Sat Jan 19, 2013 5:43 pm

How about down the dipstick tube
http://vwparts.aircooled.net/Dipstick-Oil-Temperature-Gauge-p/thermo-dipstick.htm

Sat Jan 19, 2013 6:34 pm

Hard to read from the dash...

Sat Jan 19, 2013 6:42 pm

Hotrodvw wrote: Hard to read from the dash...
I agree but it is a nice piece. and it is more accurate than any of the temp gauges on the market. it reads temp in the sump and that's as accurate as it gets.

Sat Jan 19, 2013 6:44 pm

True, but there are better ways to do it. Useless to me if I can't see what's going on under load.

Sat Jan 19, 2013 10:34 pm

I can confirm that the relief plug sensor reads lower due to air moving over it.

My setup includes three sensors, and a rotary switch to select which one shows up on the oil temp gauge.

Sender in the Feed line to engine "F":

Sender in the dry sump Tank "T":

And a third sender in the Oil pressure relief plug position (flywheel end) "E". (not pictured). You can see a significant difference between the three sensors as the engine heats up. Obviously the oil tank is the slowest to come up to temperature with 10L of oil in the whole system. Once the system is up to normal operating temperature (200deg), the temp stays relatively stable across all three sensors. The setup allows me to watch the tank to determine when the system is fully up to temp and ready for racing, I use the engine sensor to monitor temps normally, and switch to the feed if I'm seeing increased oil temps and/or want to diagnose the cooler/fan setup.

But my post started with being able to confirm the relief case sensor reads cool due to airflow over it. How?

I run a skid plate underneath my engine. With the plate installed, my oil temps are essentially exactly the same across all three. Remove the skid plate, and the sensor in the relief plug will drop 15-20deg. The amount of temperature drop is directly related to the traveling speed of the vehicle. Stop-and-Go around town and the temp senders match, hit the highway for a length of time and 20deg cooler. The airstream _does_ effect that sensor location.

-Dave

Sat Jan 19, 2013 10:36 pm

Good to know.