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leadfoot · Posted: Sun Aug 14, 2005 7:09 pm Post subject: Oil plug

I have recently mounted an oil cooler into my car, finally cured the oil light from coming on on hard turns. No matter how many hard turns I do in a row I never see the light come on which makes me feel alot better when accelerating out of hard corners.
What I didn't have was a sensor to feed me my oil temp. I was thinking of making a block to house a sensor and running the sensor pre cooler so that warm up temps can be measured, then moving it to post cooler to see the change in temperature readings.
What I would like to do though is finally mount the sensor in the second plug hole in the back of the oil pan, the one just above right of the drain plug. I believe this serves as the return oil line in the turbo application.
What I'm unsure of is whether the normal oil level is above or below this hole and whether the sensor would receive an accurate reading.
I think it would be neater to run the wiring up the back of the bell housing and have less wiring resistance to deal with. Any thoughts as I would then match my sender to this bolt hole pattern and tap my makshift block accordingly.
Leadfoot
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Peter_in_AU · Joined: 29 Jul 2001 Posts: 2745 Location: Sydney, Australia

from what I remember "the second plug hole in the back of the oil pan" was designed to hold an oil temp sensor.

Take a look at the current-flow diagrams for the 1976-1977.5 cars in the Haynes. "G8" on track 60 is described as an "Oil Temperature sender unit" and "G9" is the Oil Temperature Indicator.

Anyone with an early car have an oil temp indicator in their car?
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1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

My friend has a '76 NA and in his car he has oil temp gauge and sender stock. It's located in the threaded hole above the oil drain plug.
Leadfoot, the location is correct for the sender.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold

'84 924, turbocharged, sold.
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leadfoot · Posted: Mon Aug 15, 2005 4:18 pm Post subject:

happy days then...
any idea what the size of the thread is??
I believe it might be around an M14/M16...
Leadfoot
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

If you change your own oil I suggest you get a spigot. Performance Products has one. All you do is turn the spigot and the oil drains. You never get your hands dirty. Same as a drain plug and if you have to remove it put a wrench on it.
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"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

Smoothie · Posted: Tue Aug 16, 2005 1:01 am Post subject:

It should be m14x1.5 - http://www.924board.org/viewtopic.php?t=14376&start=5
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Smoothie · Posted: Tue Aug 16, 2005 2:50 am Post subject:

-or M16x1.5

- http://www.924board.org/viewtopic.php?t=14376&postdays=0&postorder=asc&start=22
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Lizard · Posted: Tue Aug 16, 2005 2:53 am Post subject:

this bolt hole was also used on 931 with a banjo bolt to return the oil from the air oil seperator.
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3 928s,

Smoothie · Posted: Tue Aug 16, 2005 4:32 am Post subject:

Just checked it (the banjo bolt there) with a die. Mine's definitely M14x1.5.

leadfoot · Posted: Tue Aug 16, 2005 3:51 pm Post subject:

Yeah, I can remeber doing a partial oil change through that hole and I think I syphoned the rest out with a transmission hook filler...
I definately want one of those easy drain plugs for the oil though...
Thanks guys
Leadfoot
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

leadfoot · Posted: Sun Aug 21, 2005 2:20 pm Post subject:

Some of the pics from the oil cooler install, the thermostat is behind the radiator. It might seem as though there is not much airflow around the cooler but there are three holes just above where the cooler is mounted and there are the holes above where the badge panel is located.
As heat naturally rises this should draw in air from the front dam. The cooler is massive compared to the 931 coolers and was a real challenge to mount with the intercooler already in place.
It has allready noticeably removed heat from the engine at long term driving temperatures as well as cured the oil light coming on when doing hard cornering as there is now an adequate amount of oil in supply.
The only problem I have encountered is with the sandwich plate, which looks as though it had been designed for use without the right angle adapter for the oil filter.
I am using the adapter with the solid lines running close to the exhaust manifold, but I will change them for braided lines if I find them to be of a problem when I mount an oil temp gauge.

Is there an ideal temperature to be operating the oil at ??
around 82 - 100 Degrees?? I suspected mine always ran on the hot side because it used to go black quicker that I would have thought it to normally.
After the efi conversion the cars thermofan power supply would be shut off when the cars ecu was also turned off. I could have rewired the fan to be running off another 12V line so as to have a dual operating circuit, but as I was having the oil heat problem I thought I would try and find a better solution. I used to dump coolant occaisionally as a result of heat soak in the cylinder head. I can now shut off the engine with no worry of this happening anymore.
Also has anyone used a wurth or similar additive on oil changes to help clean out the oil lines?? I read the bottle but could not find any information on whether it is safe for an aluminium head.
Thanks
Leadfoot[/img]
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Tigger937 · Posted: Fri Aug 26, 2005 8:26 pm Post subject:

Leadfoot, I seem to recall ideal oil operating temperature 200°F - 230°F, that's 93°C - 110°C. The oil needs to get hot enough to burn off any contaminants like condensation, thereby setting a lower limit.

I also recall that for every 18°F (10°C) increase in temperature above normal operating temperature, the oxidation rate (and hence breakdown) of the oil doubles. This improves with synthetics. That would explain the problem with your oil turning black quicker.

Don't know about the Wurth, but in the past I've occaisionally used Gunk 5 minute Engine Flush without any problems. It's a petroleum based solvent.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"

Paul · Posted: Sat Aug 27, 2005 8:17 am Post subject:

180 degrees F is considered the ideal oil temperature in air cooled aircraft motors. It's more than hot enough to remove water.

Tigger937 · Posted: Sat Aug 27, 2005 11:35 pm Post subject:

Paul, with all due respect, that's a different application. Contaminants also consist of acids (a normal combustion byproduct), raw fuel, sludge, etc. In an automotive environment, the amount of contaminants in the oil is generally much higher due to the widely varying conditions.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"