Recommended Viscosity Oil?
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On The Tree
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Recommended Viscosity Oil? I am trying to figure out what type of oil viscosity I should run in my car or if I'm already running it. I'm running a C5R if that means anything. Also how do you figure what viscosity you need to run?
Thanks
Thanks
You need enough viscosity to maintain proper pressure in all situations. More is not better. Thicker oil is less efficient, and takes more energy to move around.
5W-30 is just about perfect for most modern engines.
5W-30 is just about perfect for most modern engines.
Pressure is NOT what matters to the engine, we just watch pressure because it allows us to see deviation from normal.
Far as weight you will have folks who don't understand viscosity tell you things like 5w-30 was GM spec so use that. Reality is OEMs have a lot of concerns that are NOT about engine life, and that the "30" part is a range, one 0w-30 is thicker at operating temp than another 10w-30 and a year later as formulas change the 10w-30 might endup thicker.
If you want to worry about viscosity alone any 0w, 10w, 5w-30 or even 40 is going to do the job and picking between viscosities and brands beyond that is pretty much splitting hairs.
Someone wants to argue that please put up the UOA results.
Far as weight you will have folks who don't understand viscosity tell you things like 5w-30 was GM spec so use that. Reality is OEMs have a lot of concerns that are NOT about engine life, and that the "30" part is a range, one 0w-30 is thicker at operating temp than another 10w-30 and a year later as formulas change the 10w-30 might endup thicker.
If you want to worry about viscosity alone any 0w, 10w, 5w-30 or even 40 is going to do the job and picking between viscosities and brands beyond that is pretty much splitting hairs.
Someone wants to argue that please put up the UOA results.
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On The Tree
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I contacted finish line performance and they recommended 20w-50. That's what they run in their C5-R motors. Out of curiosity I also contacted Pratt & Miller and they concurred with running the 20W-50. They said it's what they ran when they used that block.
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I thought about a C5R a few years back, nice block. Do you know the bearing clearances? Also, Katech did a lot of work with that block in the C5R race car, you might want to ask them as well.
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On The Tree
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Don't know the bearing clearance since I'm not the original builder. Car is brand new to me. Good idea I will contact Katech today, why didn't I think of that. Thanks!
First of all you should be asking the builder who put the engine togther for recommendation as they are the ones that know the clearances and what type of lubrication those need. And they will probably be the one either offering some sort of warranty or who you will be going back to in case there are any issues with the engine. So you want to follow what they say.
As a general rule of thumb, you want something thick enough and resistant to shearing at high loads that you might expect the engine to see and thin enough at cold startup that it will flow well in whatever temps the engine will see.
I personally run a 0w40 in my LS2 just because I tend to use it in really cold weather hence the first number, and also have heard and read that LS engines like slightly thicker oil especially older ones.
OEM oil recommendations are around fuel economy and not so much engine life. Most manufacturers could care less if an engine lives 100k or 200k as most likely the car will be long out of warranty by then. That's why you're starting to see oils as thin as 5w20 in mainstream cars. Alot of the hipo European cars require upwards of Xw50 or 60 oils for protection. Now obviously that depends also on the clearances built into the engine, but ultimate protection also has to do with it.
As a general rule of thumb, you want something thick enough and resistant to shearing at high loads that you might expect the engine to see and thin enough at cold startup that it will flow well in whatever temps the engine will see.
I personally run a 0w40 in my LS2 just because I tend to use it in really cold weather hence the first number, and also have heard and read that LS engines like slightly thicker oil especially older ones.
OEM oil recommendations are around fuel economy and not so much engine life. Most manufacturers could care less if an engine lives 100k or 200k as most likely the car will be long out of warranty by then. That's why you're starting to see oils as thin as 5w20 in mainstream cars. Alot of the hipo European cars require upwards of Xw50 or 60 oils for protection. Now obviously that depends also on the clearances built into the engine, but ultimate protection also has to do with it.
Thread Starter
On The Tree
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First of all you should be asking the builder who put the engine togther for recommendation as they are the ones that know the clearances and what type of lubrication those need. And they will probably be the one either offering some sort of warranty or who you will be going back to in case there are any issues with the engine. So you want to follow what they say.
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On The Tree
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Lingenfelter said the same pretty much but said bearing clearance plays a roll too. Grrrrr... wish I could talk with the original builder on this.
Launching!
Joined: Jun 2006
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From: Middle of MI
I can't speak to how well these engines will hold up after 100k, as that's the oil they're designed around, but I know that fuel economy is a major factor. The harder it is to pump, the more fuel you use.
I can't speak to how well these engines will hold up after 100k
For hardcore car guys like us who like to have fun and drive our cars hard at the strip or track I don't think that type of oil will protect the engine enough.
You may never know what the bearing clearances are so I would consider what you do know like.
What start up temperatures will be.
What normal operating temperatures will be.
What rpms the engine will see.
What engine loads will be.
I run 10-40 in the summer in all my vehicles and 5-30 in the winter, I live in the Midwest and we see extreme swings from one season to the next. 100+ in the summer and well below 0 in the winter.
When I raced (circle track) I ran 20-50 with a zinc additive because the motor saw sustained high rpms and loads lap after lap.
What start up temperatures will be.
What normal operating temperatures will be.
What rpms the engine will see.
What engine loads will be.
I run 10-40 in the summer in all my vehicles and 5-30 in the winter, I live in the Midwest and we see extreme swings from one season to the next. 100+ in the summer and well below 0 in the winter.
When I raced (circle track) I ran 20-50 with a zinc additive because the motor saw sustained high rpms and loads lap after lap.
I live in the Midwest and we see extreme swings from one season to the next. 100+ in the summer and well below 0 in the winter.
TECH Junkie
Joined: Dec 2005
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Couple of questions. What weight oil are you running now? What is your oil pressure at idle both cold and hot? What is your oil pressure at rpm with the oil hot?
I have an LS3 based 427 with slightly large bearing clearances and I was running a 5W30 oil and the oil pressure was to low for me. I changed to a 10W40 and things are much better. I am considering a 5W50 synthetic or so when the motor is broken in. I also live in Southern California so the weather does not get that cold.
I have an LS3 based 427 with slightly large bearing clearances and I was running a 5W30 oil and the oil pressure was to low for me. I changed to a 10W40 and things are much better. I am considering a 5W50 synthetic or so when the motor is broken in. I also live in Southern California so the weather does not get that cold.