Some cooling issues with my car (oil temps and odd pressure readings)

Chris_Red_V8

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(Warning in advance, rambling ahead)

Background: Built a new coyote/roadrunner motor a while back. Went overboard on cooling and sensor package, and now have some weird symptoms that may be bad gauges or setup.

Setup: MMR1000/Roadrunner, Fluidyne radiator, MMR head cooling mod, Boss 302 Oil cooler, homebrew Air/Oil cooler (-10AN lines, supposed 20,500 BTU core), 302S Grilles, speedhut gauges in stock location with T, and in Moroso 10QT pan (total 12 QT capacity for system). 302S hood, wrapped headers (stock).

Symptoms:
Oil temps read 140 if not below if the ambient air is 70* or below and car is highway cruising. Can go 50 miles without fully warming the oil (as read by the gauge).
Oil pressure reads 70-90 on start, settles to about 20, and once coolant reaches about 160, oil reads no pressure on the speedhut gauge unless you blip the throttle (obviously I have pressure or the stock pressure switch would flip - I know it works unfortunately). That or my motor seems to run just fine without any oil pressure (jk)...

I did install a 180* oil thermostat last week to try to combat the temperature problem

Testing: I bought an IR thermometer to test with this evening.
After a 15 minute drive and 5 minutes of idling, the gauge showed 160 (climbed from 145 when I first parked). The Pan as shot by the thermo was 161, the oil cooler lines were 178 and 170 respectively at their fittings. The cooler core was 158 as best as I could shoot it. I am thinking something about that pan may be such that the sensor is getting more of a reading of the pan itself, which may be slightly lower temp than the oil itself. Still not sure why that would be the coolest place in the oiling system. This was all sitting idling in the garage without the car's fan operating. When it did operate, all temps dropped about 5-7*.

Some images of the setup:
maint5.jpg


maint8.jpg


oilcooler2.JPG


Can't see the gauge wiring, but I have good grounds on both gauges, oil temp is in insert in side of pan with an appropriate brass NPT adapter.

~70mph after 30 minutes continuous running, ~68* ambient. Pressure looks good, temp can't be right.
http://www.chris-wynne.com/coyote/oiltemp.JPG[/img]

My thoughts:
The system is too large a capacity for street use, however actual oil temps are higher than the gauge is reading. Is it possible both my gauges just read somewhat low? I'd be inclined to believe both read between 10-20% low. I'll email speedhut for further guidance, but anyone else have some thoughts on a car that seemingly runs too cool?
 

Chris_Red_V8

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Another update: Colder day (44 out) but I did wrap the core.

It didn't seem to make a meaningful difference on a 25 minute drive.

Some more pictures:

The sender in the pan (note the secondary ground wrapped around it):
oil_sender.JPG


the cooler core:
oil_wrapped.JPG
 

twistedneck

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Its quite possible your oil could be way to damn cold. Have you got the oil to 200F yet? that would be the normal range on a hot summer day. Also, looks like you have a lot of brass fittings for a very small oil line, those fittings could easily be cooling by convection and reducing the oil temp in that small area.
 

pufferfish

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Adding the air to oil cooler with the boss water to oil cooler seems to very commonly result in slow heat up. It's the trade off to manage heat on track. A thermostat controlled bypass may be in order if you do a lot of street driving. I am considering rigging something like this up for mine when I take the plunge on an air to oil.

But also remember that the taking a reading from the pan, while it is the most consistant place to read from, will read lower than what most people will expect to see. So, don't look too far into the number. Look more at the combination of temp and pressure.

As for pressure, that is the one I would be really concerned with. If your gauge is consistant, then the gauge is probably right. Even if it's 20% off, 20% off of zero is still zero! Judging entirely by your cold-to-hot readings, you either have loose bearing tolerances or the wrong oil...or the wrong oil for a loose toleranced engine. What oil are you using? Brand and viscosity. Have you tried different viscosities?
 

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