THSCC Forums

In trying to understand my oil temp issues for my track car, I'm wondering about location where the temp is measured.

Currently, I measure where it comes out of the block to go to the oil filter and cooler. This is directly after the oil pump and the oil is under pressure.

I know if I take measurements from the oil pan, it will be significantly lower (~30*F IIRCC). What I don't understand is why would the oil pan temp would be more desireable than what's coming out of the block.

In asking this question, I'm really looking for a good explanation as to why a certain location would be more desireable.

_________________
“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

This may not be much help, but I would think that temp as it exits block (prior to cooler) is going to give you a better idea what the temp is inside the engine while post cooler should tell you if your cooler is giving you a good delta before going back into the sump/engine.

I would see that knowing both values would be good for troubleshooting purposes.

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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

I see 4 locations that would be provide a picture of what's going on with the engine oil temps.

1. Coming out of the block (enroute to remote oil filter)
This tells you how hot the oil is after getting pressurized by the pump.

2. Coming out of the oil filter (enroute to oil cooler)
This location the beginning of the oil cooling circuit.

3.Entering back into the block (enroute to the rotating assemblies)
This location is the end of the oil cooling circuit.

4. In the crank case (drain plug)
This location gives you an ambient oil temp.

The Delta T between locations 2 & 3 show you how much heat your oil cooler system is loosing.

The Delta T between locations 3 & 4 show you how much heat the oil picks up from the rotating assemblies.

I'm pretty sure location 1 is the hottest point of the four. I would imagine that location 3 is the coolest.

Locations 1, 2 & 3 are under pressure. Do oil temps under pressure need special considerations?

The oil I run (Amsoil 5W30) starts breaking down at 304*F.

_________________
“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

Kevin, it seems to me the only thing of concern to me while on track is the max oil temp. everything else is nice to know but really superfluous.
If your oil temp exceeds 305 degrees and you wipe bearings what do you care about oil cooler temp, ambient temp, ETC,ETC. Your engine is shot. The times when the rest of the temps are relavent is when your trouble shooting, not driving. Bottom line Max oil temp is a must the rest is just nice to have.

That's the way I feel about it too Bernie (great minds think alike )

It's just that I haven't yet devised a way to reduce the temps in over 2 years of trying.

Also I tested my oil temp sender yesterday. I was hoping to find that it was reading in error. Well it was. But rather than reading 45*F too high as I hoped for, it read 15*F too low. So if I think I'm running 280*F on the track, I'm really running 295*F. That's getting awfully close to the 304*F limit of the Amsoil I run.

I used my Craftsman voltmeter thermocouple as my reference. Maybe it's off too? I used a hotplate and pot of water next to the car with the sender suspended at the top of the water line. I got as much of the sender in the water as I could without submerging the output connection. I didn't concern myself too much with the ground. The thermocouple was along with it with the tip of the thermocouple being at the end of the sender.

The only other location that I would have faith in would be at the pressure sender. It is located midengine, towards, the top of the block. It would involve installing a tee to facillitate mounting both the Pressure and Temp senders. The additional cantilevered weight being subjected to all that vibration makes me shy away from that idea though.

_________________
“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

That won't work. The sender needs to be in the path of oil that is being moved to get an accurate reading. I've been there, done that on my Z-24 using a tee off the pressure sensor and it didn't work. My Miata's oil temp gauge is in the pan.

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Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)