Oil Cooler/ Oil Questions

[93ltng]

I'm Falling into the sink hole that is Internet oil discussions. The Current set up is pretty high horsepower for the stock block (aftermarket rotating assembly) and I would like to do everything I can to protect the Engine.

I am currently running Penn Grade 1, 10w-30 Oil which is what have been using for a while. Engine bearing clearances were assembled within factory tolerance. I was using this oil in particular, for the advantages regarding flat tappet camshafts. I did a roller conversion last month and I also run E98 at the track. I read some posts online indicating that a while back Brad Penn had released a Service bulletin around 10yrs ago advising not to run the Penn Grade with ethanol due to customer issues. The webpage link/ URL did not seem to exist anymore so I could not read the bulletin. Don't know if they have corrected this issue or not but it has me wanting to switch. I think I have settled on running Valvoline VR-1 Oil

Another concern of mine is oil pressure. I have an aftermarket digital pressure gauge and I monitor the oil pressure carefully. I have noticed an oil pressure drop and Idle with enough heat built up in the engine. With the hood on and in traffic, sitting idling fully warmed up. Idle oil pressure is 25psi normally but if it gets hot it drops to 18 or 20. Higher up in the rev range it can get towards 70psi I believe. The Coolant temps are always fine 180-190, I have a big 3core radiator electric fans.

I contemplated running a heaver oil but this comes with other concerns and I feel like the information I am getting should lead me to focus more on oil temperature rather the the oil weight. Any major concerns with adding an oil cooler? Reduction in flow and or pressure? My gut says that the cooler oil temperature should offset any reduction in flow, particularly with a properly sized oil to air heat exchanger which does not create a restriction. Right?

The Current Oiling system highlights are as follows:
Factory Oil cooler removed
Hardened Oil pump driveshaft
Melling High Volume Oil pump
-4 line feeding Vortech V1 supercharger

Any thoughts or experiences are appreciated, Thank you.

 

[Raymond_B]

So I run Valvoline 10w-30 VR1 with E85. In the Tx heat at idle I will drop down to 28-30 psi idling @1000 RPM. I think your oil pressure is OK, what is your idle RPM?

 

[FMOS Racing]

Definitely don't go to thicker oil to try to fix "pressure." Run an oil based on your bearing clearances. Pressure is a measure of restriction, not performance. Flow is the critical parameter, and thicker oil may give you higher pressure, but at the cost of flow. You want enough oil flow to cool the bearings and maintain a fresh film between the journals and the bearings.

You have plenty of oil pressure and you're running good oil.

Both of my trucks have a hot soaked idle oil pressure of about 15 psi with 10W30, either Mobil 1 or Valvoline high mileage synthetic. They both run mid 40s psi at cruise and stay over 10 psi per 1000 rpms at WOT (closer to 10 per 1000 plus ~15), which Smokey Yunick said was all the pressure you need.

The Ford switch trips at 7 psi. Early motors were splash oiled.

[Edit] If you really care about the engineering geekiness of what goes on, most of the pressure of the "hydrodynamic film" (h-film so I don't have to retype that) that supports the rotating parts is generated by the rotation of the parts and is much higher than what you see from pump pressure. It's dependent on viscosity and temperature, which is why you choose an oil viscosity based on bearing clearance. The big factor in what is going is that the oil "residing" in the h-film gets hot fast, so it has to be replaced by fresh oil. This is where pump pressure and flow comes in. You need enough pressure to push the old h-film oil out and replace it with cooler oil, and enough flow to make sure plenty of fresh oil is coming in to carry away that heat.

Our 351s have a high h-film pressure in the mains because of the large journals, that's a good thing. But the downside is that there's a lot of surface to surface velocity difference, which puts more heat into the oil.

You won't hurt anything with an oil cooler. I don't think you'll see much of a change in pressure from it, but you've got plenty of pressure as it is. In reality, unless you're doing road courses or towing up long inclines, you probably won't see much of a change in oil temperature, either.

I don't think I've ever heard of anyone spinning a bearing in a 351W unless there was a failure of the oil pump (or the pump pickup was compromised). I'm sure there are some high RPM or road course failures out there.

 

[slow94]

Sounds like your oil pressure is just fine. However, I never heard the Penn grade thing with ethanol. I am running 10w40 Penn grade in my new engine and will run nothing but ethanol based fuel.

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[93ltng]

Thanks for taking the time to write that up. I think I will just keep an eye on it. It will not be seeing any road course use anytime soon. I suppose I could look into an oil temp sensor before I get crazy with a cooler.

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[oilwell1415]

The only thing I've got to add that hasn't been said before is that oil brand really isn't that important as long as you're getting an API certified oil or an oil from a reputable manufacturer that is appropriate for your application. I have to add that last part because the best oils generally are not API certified just because they don't sell enough of it to justify the expense of going through the certification process.