How much cooling does engine oil do?

Bullshark said:
Ok, here is a EE's take at addressing the question. Maybe there is a thermodynamics engineer out there that can add some credibility.

Oil has roughly 1/3 the heat capacity of water, which means it isn't a very effective coolant. The flow rate of the oil to the point of heat transfer is low in comparison to that of the water based engine cooling system. The delta T of the oil and its heat transfer points is small. ( i.e. engine block, oil pan, etc.) So, for those applications where there is no oil cooler radiator, the effect of oil as an engine coolant is very small in comparison to the primary water cooling system. Which means that you can get much better effect improving your primary cooling system. For those very high demand systems that need to eek out every degree, the oil coolers can help. I would be interested in hearing a more expert and detailed explanation if there is anyone out there who has a better analysis.

I would think the main reason for cooling the oil is to keep the lubrication qualities optimum?????

Bullshark
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Bullshark the numbers I've seen have been water does around 40% of the cooling and oil does around 60% of the cooling. I know the water has a higher heat transfer rate but just thinking about it (no science here) oil covers more surface area of the engine. The rings have the job of transfering heat form the piston head to the cylender walls. The rings are cooled by the oil along with just about every machined area in the engine. There is allot of heat transfered to the oil form the engine.

It would be great to have someone in this feild chime in and shed some light on this subject.

I'm still learning form here and through life experiances. As all here know I've been spending allot of time trying to figure my cars cooling issues out.

Neal
 
I agree with Bullshark. A good oil cooler is to cool your oil, not your engine. I have an air cooled engine, and plenty of good cool oil is key to engine life and performance. Oil that is approaching 300 degrees, even if it is synthetic, isn't doing you any good.
Bee Jay
 
wont be able to paint the bumper till this weekend so I started working on sealing the front area to force all the air through the radiator.

I made this deflector to cover the holes were the vacuum canister brackets passed thrugh the spoiler/valance area. May also help divert air up to the radiator

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Neal
 
Bullshark said:
Ok, here is a EE's take at addressing the question. Maybe there is a thermodynamics engineer out there that can add some credibility.

Oil has roughly 1/3 the heat capacity of water, which means it isn't a very effective coolant. The flow rate of the oil to the point of heat transfer is low in comparison to that of the water based engine cooling system. The delta T of the oil and its heat transfer points is small. ( i.e. engine block, oil pan, etc.) So, for those applications where there is no oil cooler radiator, the effect of oil as an engine coolant is very small in comparison to the primary water cooling system. Which means that you can get much better effect improving your primary cooling system. For those very high demand systems that need to eek out every degree, the oil coolers can help. I would be interested in hearing a more expert and detailed explanation if there is anyone out there who has a better analysis.

I would think the main reason for cooling the oil is to keep the lubrication qualities optimum?????

Bullshark
Click to expand...

I would agree. The cooling system cools the engine, and an oil cooler cools the oil. :D
 
Update to cooling my 496BBC

Well finished the cross brace and installed it, painted the bumper and got it installed, mounted the headlights and installed the hood.

Took it for a shakedown run,

The temps are at 85* with low humidity 40% so I'll still have to wait for a hot day to really tell how much good I've done.

Took a 1 hour drive, first on a local hwy cruising at 3000 rpm (60 mph) for around 20 minutes. Water temp was at 150* and oil temps were at 185*at the inlet of the cooler, pulled onto the interstate and kicked it up to 3500 rpm (70 mph) temps climbed to about 165* and the oil temps crept up to about 210*. I was at 3500 rpm for around 30 minutes, temps stabilized and stayed there till I exited the interstate. Once off the interstate and in town the temps dropped to around 155* to 160* and the oil temp dropped to around 190* at the inlet of the cooler and stabilized.

All in all I'm pretty happy with the results, I dropped about 60 lbs by removing the vacuum reservoir/core support and the crossbar at the bumper, but I added around 15 lbs with the new core support and the new crossbar, that is a total weight loss of 45 lbs on the nose of the car and appears to have helped the cooling also.

Of all the changes that I've made I would say the oil cooler has made the largest difference followed closely by opening the front bumper up were the plate would be mounted and removing the clutter (reservoir and crossbar).

The real test will be 60% humidity and 100* next summer.

Thank everyone for all the help to this point.


Neal
 
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When I didn't hear from you for days, I assumed you were spending time with the family. I should have known you were working on the car. Pictures? Especially of the cross bar and brace. I would put that oil cooler out front in the breeze. 85 degrees is a hot day around here. Itseems you have solved your water overheating problem. Good work. Why are you turning 3500 rpm at 70mph. What tranny do you have again. Sounds like you need another gear.
Bee Jay
 
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Bee Jay said:
When I didn't hear from you for days, I assumed you were spending time with the family. I should have known you were working on the car. Pictures? Especially of the cross bar and brace. I would put that oil cooler out front in the breeze. 85 degrees is a hot day around here. Itseems you have solved your water overheating problem. Good work. Why are you turning 3500 rpm at 70mph. What tranny do you have again. Sounds like you need another gear.
Bee Jay
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Were building a small camp on a local river for a getaway on the weekends, been busy there, haven't had much time to spend on the car (a little time after work during the week).

I'll get some pics and post soon.

I think I'm going to work on the AC before I move the oil cooler to the front to make sure it don't interfere with the condenser.

I was surprised when the oil temps went 40* above the water temps. Most everyone says that there oil temps are 20* to 30* over the water temps. I was also surprised when the oil temps went that high just cruising down the interstate.

85* is cool here after some 100* days with 65% humidity.

Yea I'm pretty sure I have control of the temps, last year even after it cooled off here it would still run 210*.

I'm running a TH350 with 4:11's out back, been trying to figure out what OD trany I want. Not too keen on the 700,s low first gear and 200's are getting a little hard to come by around here. I have a friend here that has a trany shop, he's waiting on me to make my mind up and tell him which one I want so he can build it for me.


Neal
 
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Here are the pics of the crossbar, sorry I didn't take some before the bumper install. I still have to make the mesh screens for the openings in the bumper and come up with some marker lights. Gota pull the bumper off and do some more cleaning and painting when I have some more time for the car.

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Neal
 
496BBC said:
Bee Jay said:
When I didn't hear from you for days, I assumed you were spending time with the family. I should have known you were working on the car. Pictures? Especially of the cross bar and brace. I would put that oil cooler out front in the breeze. 85 degrees is a hot day around here. Itseems you have solved your water overheating problem. Good work. Why are you turning 3500 rpm at 70mph. What tranny do you have again. Sounds like you need another gear.
Bee Jay
Click to expand...

Were building a small camp on a local river for a getaway on the weekends, been busy there, haven't had much time to spend on the car (a little time after work during the week).

I'll get some pics and post soon.

I think I'm going to work on the AC before I move the oil cooler to the front to make sure it don't interfere with the condenser.

I was surprised when the oil temps went above the water temps. Most everyone says that there oil temps are 20* to 30* over the water temps. I was also surprised when the oil temps went that high just cruising down the interstate.

85* is cool here after some 100* days with 65% humidity.

Yea I'm pretty sure I have control of the temps, last year even after it cooled off here it would still run 210*.

I'm running a TH350 with 4:11's out back, been trying to figure out what OD trany I want. Not too keen on the 700,s low first gear and 200's are getting a little hard to come by around here. I have a friend here that has a trany shop, he's waiting on me to make my mind up and tell him which one I want so he can build it for me.


Neal
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Dang, 4.11s with no overdrive behind a big block. You must own an Exxon Mobile station. I went with the 700R4 twenty years ago and love it.
Bee Jay
 
Yea the 4:11's were in when I bought the car, not my first choice but not bad enough to change them.

Mileage is not terrible, I'm able to run 15.5 AFR at idle and cruise at 14.2 to 14.7 AFR.

I haven't checked the mileage due to not taking any decent trips but that may change now.


Neal
 
496BBC
Thanks for adding the cross bar pictures, they clear that part up. That 4:11gear has got to kill any hope of decent mileage. As soon as I get my garage cleaned and organized, I will be replacing my radiator and digging into front end mods. Thanks again to you and Bee Jay!
 
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this is some afr logs while cruising at 3000 rpm and 3500 rpm. Their a little blurry.

The green line is vacuum, the purple line is AFR, the black line is RPM and the red line is throttle position.

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Neal
 
What are you using for a rad? I have a 572 in my car and the only time it gets warm is if i let it sit and idle and even then it only climbs to 195 - 205. I use a dewitts 76 big block rad and coolings fans out of a 94 vette and a temp switch out of Kcar (it turns on at 180F). The only time my car ever got to 230 on the road, was with the stock 350 and a rad full of dirt. On the road my 572 sits at 180, right on the thermostat. I have a oil temp gauge out of an 81 in mine and the only time i can get the temp to climb any amount is when i have the pedal burried in the floor mats, and i don't think i have ever seen that go over 270 and it comes back down to coolant temp shortly after you get out of the throttle .. so i realized that an oil cooler isn't necessary, and never bothered installing one ... but i should mention that a really hot day around here is 90 and those days don't happen to often, its usually around 70 - 80 around here. Also i changed to the 80 style bumpers on mine and used all the 80 brackets, eggcrate and crash bar. Having heating problems at highway speeds usually indicates that the rad is not working ... the only time my cooling fans come on are when the car idles.
 
Mr.Kiss, I started with a Tru-Kool universal aluminum radiator form
SpeedWayMotors and a Mark VIII fan but this would not keep it cool. I installed a Dewitt direct fit radiator and dual Spal fans and still had cooling issues.

I've talked with many people here and on other forms to try and figure out what my issue may be but have been unable to pin point the issue, if there is one, with my engine temps.

I still have a good bit of troubleshooting to do form suggestions or members here on the forum. I plan to work on them as I get time. For right now I have control of the temps after installing a very large oil cooler.

I think my issue may be that I have a 454 block bored .060" over, stroked and installed in a corvette.

There are members here that have no trouble with cooling their BBC and others that do, I just happen to be one that does. I'm sure I'll stumble across the issue and will fix it and I'll look back and laugh (I hope) at all the work I've put into this issue.

My next move may be to pull the engine and take a look at the head gaskets and the block. I'm planning on installing an OD trany so that may be a good time to pull the engine.

Neal
 
You are still overheating? I thought we fixed that. Yep, pull the heads. Something is wrong.
Bee Jay
 
Bee Jay said:
You are still overheating? I thought we fixed that. Yep, pull the heads. Something is wrong.
Bee Jay
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Nope, I'm able to pull the temps down to 150* on a 70* day, so I think we have it worked out.

I'm just not ready to say I'm finished, I have enough cooling to cool a GreyHound bus and I'm not ready to say I've checked every thing I can.

My oil pan has a leak and needs to be replaced so this will be an opurtune time to look at some things on the engine.

It just may be that this motor produces a lot of heat and it takes this much cooling.

At least now I can drive it without worrying about the temps.

Just gona keep checking things out when I have time.

Neal
 
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