Corvette UA0 with Redline 5w30: High Lead

Originally Posted By: OVERKILL
Originally Posted By: CT8
you will not know unless you try thicker oil. You don't need the 0W part unless you are starting up in below 0*f temps. If you want to Stay with redline try 10w-40. 15w-50 M1. Maybe 20w-50 Mobil1 motorcycle oil. You want to run the thinnest oil as not to cost you horse power yet thick enough to protect the engine when you pound on it.


Whether he needs the 0w-xx part of it or not I believe GM runs M1 0w-40 in their own Track Program Corvette's so I don't think recommending it for this application is unusual.


This is what GM puts in the european Z06 version (same engine)

DH
 
Now you've got me wondering. How does HTHSv play into the discussion of pressure viscosity coefficient? Does it matter if the "bearing" surface we are talking about is rolling or fixed (say a ball or other roller bearing as opposed to a regular babbit type)? Also, I looked back ten years worth of VOA/UOA's and am hard pressed to find a Redline test that sheared to a full lower grade. In fact most often the viscosity numbers are high for a given grade in the first place and are still very close to new when the UOA is run.

I am confused. I don't mean to outright defend the stuff if indeed the PVC metric has governing merit here but this is something I have not seen before and do not know how to evaluate. If it's "thicker" oil that is needed due to clearances why not go up to 5W50 with an HTHSv of 5.0 and 100 degree vis above 20! The first question is still probably the best - How does HTHSv relate, if at all, to PVC?

I do continue to suspect blanket suppositions relative to mineral, esters, PAGs, PAOs, et al as being generically strong or weak. We all know that lubricants are highly engineered to minimize their weaknesses and are not amenable to generalized assumptions. Apologies if I am dragging this out unnecessarily but it does look like a possibility to learn something.
 
Originally Posted By: Gokhan
Originally Posted By: Dirty_Howie
Interesting point that the motor/bearing clearances are set for operating temps and should therefore be larger accomodating a thicker oil. These LS7 motors are notorious for premature valve guide wear. I wonder what the expected result would be for this part of the motor with a thicker oil ?????

DH

I think the only negative effect of thicker oil is increased fuel consumption and a slight loss in engine horsepower. Bearings especially always benefit from thicker oil. When you mention the bearing clearances, I guess you are worried about the oil pressure (too high) or oil flow (too low) not being right when the oil is too thick but I wouldn't worry too much. Engines can tolerate a rather wide viscosity range.

Valve guides operate in the boundary-lubrication (metal-to-metal contact) regime. In this regime, thicker oil is always better. Valve-stem oil seals are made to meter the oil flow, which depends on the viscosity, but again, I wouldn't worry too much about that.

I, myself, used very thick oil in the past (no UOAs) then very thin oil (OK UOAs). I will give the thicker oil a try in the next OCI and report how it differs from thinner oil.


Yes I am worried as you stated. I guess I have heard way too much about getting the most flow not the thickest oil on startup and initial engine warmup.

With the LS7 there is a concern that the valve seal is not letting in enough oil even with Mobil1 5w30. There are many performance shops that actually are slitting the seal to allow more oil in. So thicker could be a concern.

Maybe I should try Mobil1 10w40. That would change the base stock and be thicker ........... ????

DH
 
Originally Posted By: DeepFriar
Now you've got me wondering. How does HTHSv play into the discussion of pressure viscosity coefficient? Does it matter if the "bearing" surface we are talking about is rolling or fixed (say a ball or other roller bearing as opposed to a regular babbit type)? Also, I looked back ten years worth of VOA/UOA's and am hard pressed to find a Redline test that sheared to a full lower grade. In fact most often the viscosity numbers are high for a given grade in the first place and are still very close to new when the UOA is run.

I am confused. I don't mean to outright defend the stuff if indeed the PVC metric has governing merit here but this is something I have not seen before and do not know how to evaluate. If it's "thicker" oil that is needed due to clearances why not go up to 5W50 with an HTHSv of 5.0 and 100 degree vis above 20! The first question is still probably the best - How does HTHSv relate, if at all, to PVC?

I do continue to suspect blanket suppositions relative to mineral, esters, PAGs, PAOs, et al as being generically strong or weak. We all know that lubricants are highly engineered to minimize their weaknesses and are not amenable to generalized assumptions. Apologies if I am dragging this out unnecessarily but it does look like a possibility to learn something.


As the OP I welcome any input and questions.

I don't think my reports show any loss of viscosity. And infact mention is made that it might be thicker than expected if you read it.

DH
 
Didn't mean to question you OP, not in the least. My question revolves around only the PVC issue relative to PEO's as opposed to mineral or other syn for that matter. The input about esters in general having a lower PVC (and therefore being "thinner" in practice)was just causing noise on my (admittedly limited) mental channel when I tried to square it with HTHSv and other vis measures. Forgive me if I gave offense. Was not my intention.
 
Originally Posted By: Dirty_Howie
Originally Posted By: DeepFriar
Now you've got me wondering. How does HTHSv play into the discussion of pressure viscosity coefficient? Does it matter if the "bearing" surface we are talking about is rolling or fixed (say a ball or other roller bearing as opposed to a regular babbit type)? Also, I looked back ten years worth of VOA/UOA's and am hard pressed to find a Redline test that sheared to a full lower grade. In fact most often the viscosity numbers are high for a given grade in the first place and are still very close to new when the UOA is run.

I am confused. I don't mean to outright defend the stuff if indeed the PVC metric has governing merit here but this is something I have not seen before and do not know how to evaluate. If it's "thicker" oil that is needed due to clearances why not go up to 5W50 with an HTHSv of 5.0 and 100 degree vis above 20! The first question is still probably the best - How does HTHSv relate, if at all, to PVC?

I do continue to suspect blanket suppositions relative to mineral, esters, PAGs, PAOs, et al as being generically strong or weak. We all know that lubricants are highly engineered to minimize their weaknesses and are not amenable to generalized assumptions. Apologies if I am dragging this out unnecessarily but it does look like a possibility to learn something.


As the OP I welcome any input and questions.

I don't think my reports show any loss of viscosity. And infact mention is made that it might be thicker than expected if you read it.

DH


None taken. I reapeat ....... I welcome all input !!!
 
Originally Posted By: Gokhan
Originally Posted By: Gokhan
Pressure - viscosity coefficient is also an important factor in oil-film thickness. I don't have this coefficient for ester base oil at hand but I suspect it is low and this maybe the reason for your high wear. I know some ester-based oils have performed ridiculously poorly in wear department.

If oil is the reason for high wear, you have all the reason to change not just the viscosity but even more importantly the brand. Don't fix something that is not broken but also don't insist that something broken will fix itself.

The culprit is likely the ester base oil. See Table 1 in the following link:

http://www.skf.com/caribbean/products/be...oils/index.html

Ester base oils have the lowest pressure - viscosity coefficient among all base oils. This translates as your ester-based Red Line is actually performing more like a 5W-20 or perhaps a 5W-10 as far as the oil-film thickness is concerned. This is because the oil-film thickness is not only proportional to the viscosity but also the pressure - viscosity coefficient.

Once again, switch to a proven mainstream oil.
Redline seems to say the opposite on their literature. Redline stirs the put worst than Amsoil stirs the pot.
 
Originally Posted By: Dirty_Howie
Originally Posted By: OVERKILL
Originally Posted By: CT8
you will not know unless you try thicker oil. You don't need the 0W part unless you are starting up in below 0*f temps. If you want to Stay with redline try 10w-40. 15w-50 M1. Maybe 20w-50 Mobil1 motorcycle oil. You want to run the thinnest oil as not to cost you horse power yet thick enough to protect the engine when you pound on it.


Whether he needs the 0w-xx part of it or not I believe GM runs M1 0w-40 in their own Track Program Corvette's so I don't think recommending it for this application is unusual.


This is what GM puts in the european Z06 version (same engine)Try some !that is a top notch oil and the easiest was to see if the problem is the oil is to change the oil. I doubt a tear down would be worth it at this point.

DH
 
Originally Posted By: Dirty_Howie
Maybe I should try Mobil1 10w40. That would change the base stock and be thicker ........... ????

DH

I would probably give Mobil 1 0W-40 SN a chance. It's cheap at Walmart.

It may not be much thicker than your "5W-35ish" Red Line as far as the viscosity (cSt or cP) at low pressure (oil-pump pressure) is concerned. This also should alleviate your concerns regarding oil flow because oil flow depends on viscosity. However, its oil film may be thicker when the oil is put under hundreds of megapascals or even gigapascals of pressure in the bearings when it's squeezed because its pressure - viscosity coefficient may be higher.

The reason for this is that the viscosity that is reported [KV (cSt), HTHSV (cP), etc.] is the atmospheric-pressure viscosity. When the oil is squeezed between two moving parts, tens of gigapascals of pressure, which are hundred thousand times more than the atmospheric pressure (100 kilopascal) is produced and the viscosity increases greatly. How much it increases depends on the pressure - viscosity coefficient (alpha) through this equation:

(viscosity under pressure) = (atmospheric-pressure viscosity) * exponential(alpha*pressure)
[exponential( ) is the exponential function and pressure is the pressure of the oil film squeezed between moving parts (not the oil-pump pressure, which is the flowing-oil pressure).]

So, more the pressure - viscosity coefficient (alpha) is, more the viscosity under pressure and thicker the oil film under pressure is. You can also state this as more the pressure - viscosity coefficient (alpha) is, higher the "oil-film strength" is.

See the explanation on the pressure - viscosity coefficient at this link:

Click here: Selecting oils with high pre...than four times
(Selecting oils with high pressure - viscosity coefficient -- increase bearing life by more than four times)
 
Originally Posted By: Gokhan
See the explanation on the pressure - viscosity coefficient at this link:

Click here: Selecting oils with high pre...than four times
(Selecting oils with high pressure - viscosity coefficient -- increase bearing life by more than four times)


Yes, I had read that earlier. I still have a question on that due to its being a test on gears/roller bearings and not on wider babbit-type bearings where perhaps the load is spread more widely (also noting the non-inclusion of POE in the test but cognizant of the other reasons you mention). Just wondering. The other question is, does the PCV value then more or less invalidate or reduce the utility of the HTHSv as a worthy unit of measure in PAO, and more specifically, in POE oils in automotive use? The input provided seems to indicate that since HTHSv is an "atmospheric" measure it is wholly without merit for our purposes.
 
Originally Posted By: Gokhan
Originally Posted By: Dirty_Howie
Maybe I should try Mobil1 10w40. That would change the base stock and be thicker ........... ????

DH

I would probably give Mobil 1 0W-40 SN a chance. It's cheap at Walmart.

It may not be much thicker than your "5W-35ish" Red Line as far as the viscosity (cSt or cP) at low pressure (oil-pump pressure) is concerned. This also should alleviate your concerns regarding oil flow because oil flow depends on viscosity. However, its oil film may be thicker when the oil is put under hundreds of megapascals or even gigapascals of pressure in the bearings when it's squeezed because its pressure - viscosity coefficient may be higher.

The reason for this is that the viscosity that is reported [KV (cSt), HTHSV (cP), etc.] is the atmospheric-pressure viscosity. When the oil is squeezed between two moving parts, tens of gigapascals of pressure, which are hundred thousand times more than the atmospheric pressure (100 kilopascal) is produced and the viscosity increases greatly. How much it increases depends on the pressure - viscosity coefficient (alpha) through this equation:

(viscosity under pressure) = (atmospheric-pressure viscosity) * exponential(alpha*pressure)
[exponential( ) is the exponential function and pressure is the pressure of the oil film squeezed between moving parts (not the oil-pump pressure, which is the flowing-oil pressure).]

So, more the pressure - viscosity coefficient (alpha) is, more the viscosity under pressure and thicker the oil film under pressure is. You can also state this as more the pressure - viscosity coefficient (alpha) is, higher the "oil-film strength" is.

See the explanation on the pressure - viscosity coefficient at this link:

Click here: Selecting oils with high pre...than four times
(Selecting oils with high pressure - viscosity coefficient -- increase bearing life by more than four times)


I understand. Thanks again for all the explanation.

Unless I missed something I thing the consensus here would be for me to try the Mobil1 0w40, see the UAO and go from there.

DH
 
I still wonder if there was race or aircraft fuel that accidentally got in there by the previous owner. Did he own a plane? He could have topped it off from the wrong fuel can , and never realized it.
 
Originally Posted By: DeepFriar
Originally Posted By: Gokhan
See the explanation on the pressure - viscosity coefficient at this link:

Click here: Selecting oils with high pre...than four times
(Selecting oils with high pressure - viscosity coefficient -- increase bearing life by more than four times)

Yes, I had read that earlier. I still have a question on that due to its being a test on gears/roller bearings and not on wider babbit-type bearings where perhaps the load is spread more widely (also noting the non-inclusion of POE in the test but cognizant of the other reasons you mention). Just wondering. The other question is, does the PCV value then more or less invalidate or reduce the utility of the HTHSv as a worthy unit of measure in PAO, and more specifically, in POE oils in automotive use? The input provided seems to indicate that since HTHSv is an "atmospheric" measure it is wholly without merit for our purposes.

Oil-film strength, which is determined by the atmospheric viscosity and pressure - viscosity coefficient (equivalently by the viscosity under pressure), is more important in the regime where you transition from hydrodynamic lubrication (thick oil film present) to boundary lubrication (metal-to-metal contact). This regime is known as elastohydrodynamic (EHD) regime. If your bearings didn't experience wear, you probably didn't have to worry about the oil-film strength, as you already have thick oil film. However, if you are experiencing bearing wear, this means that it's already in the EHD regime and you do need to worry about oil-film strength to reduce metal-to-metal contact. This PHD thesis (PDF link) says that 100 MPa pressure in the journal bearings is possible. So, this is one thousand times the atmospheric pressure and it's no longer atmospheric HTHSV, and you do need to know the pressure - viscosity coefficient. You would be experiencing even higher pressures if your bearings were wearing down, as the oil film got thinner and the surfaces became rougher.

Oil-film strength is certainly important in the valvetrain and parts of the cylinders and rings, where you are in the EHD or metal-to-metal contact regime.

It would be great if they could also specify the pressure - viscosity coefficient in addition to HTHSV, but it's something that is hard to measure.
 
Originally Posted By: Dirty_Howie
I understand. Thanks again for all the explanation.

Unless I missed something I thing the consensus here would be for me to try the Mobil1 0w40, see the UAO and go from there.

DH

I think that's a good first-order measure, which is neither drastic nor expensive. If it reduces wear, it's good; if it doesn't, you can look into whether you should use even thicker oil.
 
Originally Posted By: DeepFriar
I do continue to suspect blanket suppositions relative to mineral, esters, PAGs, PAOs, et al as being generically strong or weak.

I would agree with that. Red Line is a fully formulated motor oil, with its formulation geared more towards performance applications and wear protection. If we were seeing a lot of problems with other Red Line UOAs, I wouldn't be so skeptical.
 
Originally Posted By: spasm3
I still wonder if there was race or aircraft fuel that accidentally got in there by the previous owner. Did he own a plane? He could have topped it off from the wrong fuel can , and never realized it.


I have put 20K miles on it since I bought it and definitely no leaded fuel or additives !!

DH
 
Originally Posted By: Garak
Originally Posted By: DeepFriar
I do continue to suspect blanket suppositions relative to mineral, esters, PAGs, PAOs, et al as being generically strong or weak.

I would agree with that. Red Line is a fully formulated motor oil, with its formulation geared more towards performance applications and wear protection. If we were seeing a lot of problems with other Red Line UOAs, I wouldn't be so skeptical.


So are you opposed to trying the Mobil1 0w40 and see what the results are ?

I would like to proceed in a fashion that you and Gokhan would agree upon ................ if thats possible.

DH
 
I don't think anyone would argue against the use of Mobil 1 0W40 based on the VOA/UOA's we have been seeing for quite a while now and what your intended use is.
 
Originally Posted By: Gokhan

It would be great if they could also specify the pressure - viscosity coefficient in addition to HTHSV, but it's something that is hard to measure.


Interesting input, thank you. Would this mean then that unless there is a linear or close to linear relationship between measured HTHSv and PVC that the HTHSv metric is not very useful to us in the real engine world where the bearings are always in a non-atmospheric environment? Apologies for being thick. I had come to rely on HTHSv as my "go to" for practical working viscosity and this is....destabilizing.
smile.gif
 
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