Interesting Oil Temp and Pressure Question

2

23racer

New member
Last weekend, I was out testing with my Cougar (ex WC) and an interesting problem popped up. The track is a very tight track with a lot of hard second and third gear running and only into fourth a couple of times a lap. We normally run with the electric fans running. On initial startup the car generated 120+ oil pressure at idle (normal for car) and I let it warm up to about 190 water and 160 oil. I then went out on track and started building up some speed. oil temps at 4,000 rpm were about 60 lbs and rising to about 90 psi at 8000 rpm. Granted the first few laps were slow as I was feeling out the car after having just put it back together with a different gearbox. As I started to get on it the oil temps started to climb up to about the 240 degree range and the water to the 200 degree range and it all stabilized.

What was very interesting is that with the oil temps at about 240 degrees I started to get a bit concerned about temps and pressures so I pulled into the pits. The oil pressures at idle (2500 rpm) were around 55 - 60 psi and at 7,000 they had only climbed to about 75 psi. Not much pressure rise from idle. What I want to understand is why? Is it a problem with cooling and the need for more airflow with a higher speed fan? Should I go to a higher viscosity oil or a lower viscosity one? At Mosport the oil temps and pressures are not an issue as the track is a ton faster with more airflow.

After I let the car cool down fully the oil pressures were back to 120 psi cold at idle and after warming it up to 190 water and 180 oil the pressures were over 100 psi at 7000. The problem seems to be fairly localized to that one track. Air temps were over 90 F with about 60% humidity.

I am running Redline 20-50 in the motor and I know that the car is hard on oil and replace it every race weekend. The car has a 2 quart Accusump, a monster oil cooler and normally takes 8 quarts to change. The car has a 2.5l Duratec motor with 13.2:1 compression and pretty aggressive cams. I was running on an unleaded 110 octane fuel (all we can use now in Canada) and I was wondering if this could play a part as the car normally used to run on VP C12. The tech guy at Redline suggested going to their Race 40 Weight as it has better heat transfer abilities. Sounds good, but I am just trying to understand why.

I want to work out the system issues before I take this car out racing again. Improved Touring guys have to work things out from first principles to correct issues like this, so I am hoping you can help. Ideas?

Eric
 
unfortunately there are alot of variables to tell you why. A few things. though you ahve a 2qt accusump that oil is for the most part stagnet, and not moving when the engine is running. So that doesn't play a major role in cooling. Teh oil cooler definetly does. An oil temp of 240 isn't that high. Any decent synthetic oil will handle that no problem, strickly from a temperature standpoint.

Is it possible to get an oil sample to send to a lab? did it smell? dis-color? etc..

What oil was used when it was actively raced? are you running large clearances? tight clerances? you have alot of OP cold but what about flow? Does it have the stock pump?

We tired a few oils and found what worked for us. Racing oils will help disipate heat better, they also typically have other additives that will no allow them to meet API certs.

There is a decent read, though you may have to pay a few bucks for it. look up the "oil Bible". It is a few years old but the info is good.

Another thing you can do is do a standard viscosity test with the oil hot v.s cold. There are stardard tests you can find online to condut to see how it is changing with temperature. IT should change. hence the 20w50.
 
Great response and it gives me a few things to look into.

Regarding the oil, it is my understanding that the car ran Elf when it was all new, but the previous owner ran Mobil 1 and Castrol 20-50. I went to Redline as I have had great success with the oil before and was willing to try it again.

Regarding the motor, it was built by Kinetic Race Engines back in 2001 and has had maybe 20 races on it since. Leakdowns and compression checks look normal, so I believe that it is in good shape still. It still pulls like a locomotive and starts and runs great. Regarding details on the motors (I have 2) neither the Mumms or myself know the details and the guys at Kinetics aren't talking unless I bring the motor back to them for a rebuild. I am a bit leery about rebuilding the motors yet, but I may rebuild my spare first then the race motor. I will be able to find things out a bit more then. I do know that the oil pump was reworked to build more pressure.

Regarding the oil, it didn't smell, it had almost no colour to it and was clean looking.

I just read the race sheets from Sebring and the oil temps were at 250 there as well, hmmmm........ The previous owner opened up the grill area to get more airflow through the cooler, so it looks like it has been a problem for a while. Maybe all the car needs is more cooler?

Eric
 
Do you have a heater for the Accusump?(like in my Cup car). I would think you wouldn't want to run any thicker weight than 20/40 at Mosport. Not sure what guys in the south run during the summer.
 
BruceG said:
Do you have a heater for the Accusump?(like in my Cup car). I would think you wouldn't want to run any thicker weight than 20/40 at Mosport. Not sure what guys in the south run during the summer.
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No I don't.

I think I am going to put a larger cooler or maybe a supplemental water to oil cooler on the car. After talking to the guys at Redline, they told me that their oils will withstand hotter temps, but that to get the most performance out of the oil it has a sweet spot between 210 and 230. Any warmer or cooler increases wear and reduces HP.

I am going to change to Redline Race 40 WT. I also had great results running it previously in my other cars.

Eric
 
joeg said:
I think you are worrying too much about your oil temps and especially pressures.
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You may be right, but I just don't want to have to drop a ton for a new motor if this one spits a rod out. I was told a replacement motor would be close to $30,000 to match the spec of the existing motors and a bunch of pieces on the motors were custom made.

I just want to be cautious.

I beat the tar out of my RX7 and it goes like stink and is reliable. The Cougar is built to a different level.

Eric
 
BruceG said:
Not sure what guys in the south run during the summer.
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we run hot - not too much can be done about it in many cases.

redline, amsoil, mobil 1, etc.. all have good heat tolerance. 300°F is scary but the oil will survive it. SS guys see super hot oil all the time and live with it becasue they have to.

don't do the oil/water exchanger unless you believe that you have sufficient extra heat capacity in the water cooling system - last thing you want to do is overwork the radiator in an effort to reduce oil temps and end up overheating both systems. try adding a bigger or second oil/air exchanger first or adding additional oil to the system - mass helps. big pan, oil resevoir, huge external filter, etc...
 
Those temps and pressure don't sound horrific, under the conditions...

That said, before you add a larger oil cooler, make sure the cooler you're using is free and clear and getting fresh air! Often coolers just end up stuck in front of the radiator, and work more like an interheater than a cooler!

On my ITB car, where cool oil (as is, not more than 230 peak) is a necessity for longevity, we eventually went with the 8.5x11" trans cooler for oil. Works wonders, and with a stock water rad we don't have cooling issues any more. Ever. Even when pushing 100deg ambient.
 
924Guy said:
Those temps and pressure don't sound horrific, under the conditions...

That said, before you add a larger oil cooler, make sure the cooler you're using is free and clear and getting fresh air! Often coolers just end up stuck in front of the radiator, and work more like an interheater than a cooler!

On my ITB car, where cool oil (as is, not more than 230 peak) is a necessity for longevity, we eventually went with the 8.5x11" trans cooler for oil. Works wonders, and with a stock water rad we don't have cooling issues any more. Ever. Even when pushing 100deg ambient.
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The cooler thats on the car is a 8"x24"x2" Mocal. Its mounted high up and in front of the rad with about an inch of clearance. I'll double check it for obstructions. I think I am going to spend some time with my ducting to direct air directly through it and add a second cooler in parallel if the ducting won't help. I am also thinking about adding a stronger fan for the low speed/ high load tracks.

I have had to work out tons of cooling and oil issues with the RX7, but its all great now, so I guess I need to do the same for the Cougar.

Life is fun.

Eric
 
quadzjr said:
unfortunately there are alot of variables to tell you why. A few things. though you ahve a 2qt accusump that oil is for the most part stagnet, and not moving when the engine is running. So that doesn't play a major role in cooling. Teh oil cooler definetly does. An oil temp of 240 isn't that high. Any decent synthetic oil will handle that no problem, strickly from a temperature standpoint.


Relative to the quote above, I'd like to respectfully disagree. Unless you have an Accusump with an automatic pressure control valve (opens automatically when the pressure reaches a prescribed low number, and closes automatically when the pressure rises to a prescribed high number-newer model Accusumps have this option), the oil in the Accusump is essentually moving slightly between it and the oil passage as the engine oil pressure varies.

The Pressure Relief Valve in the oil pump will hold the maximum pressure, and the Accusump oil doesn't move. But when the pressure falls below the Maximum, the oil will move towards the engine to keep the pressures equalized beween the oil galley, and the air pressure chamber that drives the Accusump. As the engine pressure rises again, the oil will move to refill the Accusump chamber, until the engine pressure, and the chamber pressure equalized.

I agree with Joeg, and quote you here: "...built by Kinetic Race Engines back in 2001 and has had maybe 20 races on it since.". If it has this many races on it, I doubt that it has any issues to be corrected. It would have failed well before this time.

If I had this car, I'd follow this rule: If it ain't broke, don't fix it.

References for oil products vary on thier parameters to some degree. But, temps of 200-250 deg. F are in the ball park. Pressures seem to be dependent on the engine builder, personal preferences and experiences. A friend of mine won't change from straight weight to multi, Dino to Synthetic, because he's used the old stuff for years, and built many engines after failures he atributes to oil. What ever. I try to listen to the oil engineers, not the sales people.

Good luck with it. Sounds like a blast to drive, especially at Mosport!!

Bill:024:
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That is why I said "for the most part". Obviously the oil is moving a little bit and fluxuating with changes in oil pressure, however, it is not circulationg oil to a point that it plays a major roll in heat transfer. If it did after your race your accusump should be very hot (a few degrees below the oil temp as aluminum is a great conductor), but it is not. It may be warm but nothing near 200+ degrees of the oil in your engine.
 
billf said:
quadzjr said:
unfortunately there are alot of variables to tell you why. A few things. though you ahve a 2qt accusump that oil is for the most part stagnet, and not moving when the engine is running. So that doesn't play a major role in cooling. Teh oil cooler definetly does. An oil temp of 240 isn't that high. Any decent synthetic oil will handle that no problem, strickly from a temperature standpoint.


Relative to the quote above, I'd like to respectfully disagree. Unless you have an Accusump with an automatic pressure control valve (opens automatically when the pressure reaches a prescribed low number, and closes automatically when the pressure rises to a prescribed high number-newer model Accusumps have this option), the oil in the Accusump is essentually moving slightly between it and the oil passage as the engine oil pressure varies.

The Pressure Relief Valve in the oil pump will hold the maximum pressure, and the Accusump oil doesn't move. But when the pressure falls below the Maximum, the oil will move towards the engine to keep the pressures equalized beween the oil galley, and the air pressure chamber that drives the Accusump. As the engine pressure rises again, the oil will move to refill the Accusump chamber, until the engine pressure, and the chamber pressure equalized.

I agree with Joeg, and quote you here: "...built by Kinetic Race Engines back in 2001 and has had maybe 20 races on it since.". If it has this many races on it, I doubt that it has any issues to be corrected. It would have failed well before this time.

If I had this car, I'd follow this rule: If it ain't broke, don't fix it.

References for oil products vary on thier parameters to some degree. But, temps of 200-250 deg. F are in the ball park. Pressures seem to be dependent on the engine builder, personal preferences and experiences. A friend of mine won't change from straight weight to multi, Dino to Synthetic, because he's used the old stuff for years, and built many engines after failures he atributes to oil. What ever. I try to listen to the oil engineers, not the sales people.

Good luck with it. Sounds like a blast to drive, especially at Mosport!!

Bill:024:
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Bill I agree with your assessment. At Mosport everything is fine regarding oil temps and pressures, so I am going to spend my efforts on just improving the ducting to ensure that all the air flows through the rad and cooler. It should give me the most results.

Regarding driving the car, its a blast. It still runs competitive WC times and is the most well balanced car I have driven at Mosport. The original builders got this car right as Mosport seems like a billiard table (no bumps) and you can balance the car on the throttle through all the really fast corners like 2, 4 and 8. At Shannonville at our last test I very quickly got down to times that would have placed me in the top 6 in the last CCTCC Race there. This is with 4/5 year old RA1's.

Best handling FWD car I have ever raced. Now I just have to get my head around the $200 an hour fuel bill, :blink:.

Eric
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An apology!!

Sorry Quadzjr,

I didn't mean to sound as though I was counting your statement as wrong. My experiences (some) are with older English sports cars that used Accusump, that had poor oil pressure control in the corners. Ergo, the Accusump was active, and was constantly moving oil, and was warm/hot to the touch during the event. This harks back to the friend mentioned above.

If you have a cool unit (lucky guy), it shows, as you said, that it is not moving oil to any degree. Reasonable pan design.

Sometimes I have to remind myself that I'm old, and have played with some really inefficient automotive designs that started life as tractors (BMC), or commercial water pumps (Saab).

Again, no insult intended.

Eric,

Could I suggest that you also evaluate the air exit from the cooler? Soimetimes they are overlooked.

Good racing,

Bill:024:
 
billf said:
Sorry Quadzjr,

I didn't mean to sound as though I was counting your statement as wrong. My experiences (some) are with older English sports cars that used Accusump, that had poor oil pressure control in the corners. Ergo, the Accusump was active, and was constantly moving oil, and was warm/hot to the touch during the event. This harks back to the friend mentioned above.



Bill:024:
Click to expand...


We had the same issues with our Datsun Roadster motors with an accusump. Also an inefficient tractor motor.
 
What about trying puting a electronic fan on the cooler and mount it elsewhere? However in winter time it may overcool the oil. Maybe keep the cooler and not run the fan?
 
Just a quick thought, but with 1" of clearance between the oil cooler and radiator, how much air is getting around the cooler instead of going through it? You might try building some sort of air dam between the cooler and rad to force air through it instead of around. that coule be as simple as some foam jammed between the two for a session and see what happens. cheap and easy to remove if that doesnt' solve it.

Also, I'm used to Nissans but those oil pressures are insanely high. My car sees about 30psi when cold at idle and gets down to about 10psi hot at idle. cold, it'll go past 100psi at 3000rpm and I don't run it any higher than that till it's warm.
When I let it warm up, it's still near 100psi at 6000rpm, but again only 10psi at idle.

I'd almost be afraid of bearing washout with those pressures, but as other have said- it's got 20 races on it and hasn't blown up? Sounds like it's running good to me. don't re-engineer something that works.
 
Leakdowns and controls compression seems normal, so I think it is in good shape yet. It is always best as driver and starts and runs great. For more information about the engine (I 2) or mm or even know the details and the guys on the kinetics do not speak so I put the engine back to them for reconstruction. I am a little cautious about rebuilding engines, but I can rebuild my free time first, then turn the engine. I will be able to find things a little more than one. I know that the oil pump has been redesigned to build more pressure.
 
Wow, that looks like a great rig.

As an update to the story, I have reinstalled all of the original airduct sealing going to the rad and cooler. It looks like a lot of bleed of could have been occuring. As well I have repaired the high speed circuit on the fan and sealed off the gaps between the cooler and the fan.

I am also going to put a heat shield between the front header and the rad/ coolers/ line. The Firebraid that is slipped over the output oil line that goes to the Accusump and cooler is all nice and crispy now from the heat, so I am going to slip another sleeve over the line and try to protect it better. Anybody have opinions on the use of header wrap on stainless steel headers? My front header runs within an inch of the oil pan and wrapping it would substantially reduce oil temps in the pan.

Eric
 
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