Motul Sport Ester 5W-50

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I was scared when i installed the OP gauge and saw that happening
smile.gif
Then i spoke with a few people that also had OP gauges, it's a characteristic of this engine (and there is no aftermarket oil pump as an upgrade unfortunately).

My friend is using Castrol Edge 10W-60 in his engine (same with mine) and he also doesn't hit the bypass
 
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A positive displacement pump must not operate against a closed valve on the discharge side of the pump, because it has no shutoff head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve continues to produce flow and the pressure in the discharge line increases until the line bursts, the pump is severely damaged, or both.


So the valve inside of the pump is not a bypass per se as in an oil filter, it in fact fully regulates the backpressure. Since after a certain amount of flow is leaking from the lubrication points (bearings, heads, squirters etc), then the regulator valve is always operating. Really, the regulator is just a small piston on a spring. The further it is pushed downward, the more it progressively bypasses. What many people do is replace or shim the regulator spring so that more force is exerted on the piston. This raises the regulated oil pressure and raises the PSI/RPM point that the valve bottoms out.

What I'm estimating in the MINick's case, is that at the top of the range, with a 50grade oil, the bypass is being pushed so far down it's travel, that it opens the valve to it's highest relief point.

Quote:

My friend is using Castrol Edge 10W-60 in his engine (same with mine) and he also doesn't hit the bypass

Do you mean that his oil pressure remains static at high RPMs?

How do his pressures compare to yours throughout the rev range?
 
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MINick, not sure what you're asking, so I will just illustrate the regulator and it's parts:

xf2r9v.jpg


The red arrow is parallel to the pressure regulator assembly and illustrates it's movement.
#6 is the piston which is acted upon by gross oil pressure.
#7 is the spring that determines the regulated pressure
#8&9 looks like a bushing a shim
#10 is the retainer clip that holds all of the above in the green circled area.

Some people change the spring (#7) to a higher tension spring or put a thicker shim (#9) to achieve a higher regulated oil pressure. This is commonly how most pumps are modified. The only other modification is to increase the displacement of the gerotor (#2&3) with a wider set, for a higher volume. I rarely find the need for a higher volume pump unless your delivery side leakage is increased (via larger clearances or thinner oil).

The further down the bore that #6 is pushed, the greater the pressure bleed off. I guestimate that the volume of high viscosity oil entering the pump at high RPM is unable to flow out on the delivery side nearly as fast as a thinner oil can, and all the excess volume (which is directly correlated to engine speed) has no where to go but the regulator, which may be being pushed down into it's most open position. (just a guess)

I hope that answers at least one of your questions!
 
Originally Posted By: MINick

My friend has a different OP gauge, but he has pretty much the same behaviour, i have more OP everywhere even though my oil is thinner, but then my engine is fresh compared to his, hard to compare really


smile.gif
now do you see why I recommended an Ester 30 grade, but an {other} 40 grade? Esters tend to hold their viscosity much better at temperature, practically equaling a GrIII, for example, of one grade higher especially in those bearings. More viscosity in the bearing = less leakage = more volume of oil taken into the pump being bypassed.

Not sure what grades of oil are common in Greece, but if you can try a 30 grade, the oil pressure behavior can tell us much more about what is actually happening.
 
You gained oil pressure by reducing volume of flow.
First off you need to determine max oil temp when driving hard. Then take that temp and look up minimum oil pressure at max temp/rpm.
Now find an oil that will maintain the oil pressure at the max oil temp. That insures adequate pressure and viscosity when the oil is at its hottest.
Then use the thinnest oil you can find that meets your minimum pressure at maximum oil temp.
There is less parasitic loss with thinner oils which means more power to the wheels. Add that to thinner oils allow more volume per pump stroke which means more heat than be removed from the engine faster.
Thin as possible.
As thick as necessary.
 
Originally Posted By: Clevy
You gained oil pressure by reducing volume of flow.
First off you need to determine max oil temp when driving hard. Then take that temp and look up minimum oil pressure at max temp/rpm.
Now find an oil that will maintain the oil pressure at the max oil temp. That insures adequate pressure and viscosity when the oil is at its hottest.
Then use the thinnest oil you can find that meets your minimum pressure at maximum oil temp.
There is less parasitic loss with thinner oils which means more power to the wheels. Add that to thinner oils allow more volume per pump stroke which means more heat than be removed from the engine faster.
Thin as possible.
As thick as necessary.


A positive displacement oil pump displaces the same amount of oil per revolution if it is TGMO 0w-20 or TWS 10w-60. The volume is constant at a given RPM. Whether some of that oil goes out the bypass or all of it is forced through the engine is determined by the bypass pressure on the release valve. The pressure observed on the gauge is simply indicative as to the level of restriction in the system. And can tell you if the bypass is open or not.
 
Guys, the OP drop after 6000rpm is happening even on Castrol edge 0W-40(i was using it for 2-3 oil changes before the built engine, i didn't like it because it was always showing increased oil consumption, compared to zero with the Motul 8100). The difference is, that with the 5w50 Motul, the OP is elevated a few psi everywhere in the rev range.
I think that the oil pump does not provide enough flow after 6k rpm, and causes the OP drop. I don't really mind, i am not trying to solve this by using a thicker oi, i just want to know that the oil i am using is ok for my engine, and i know that this is the right place to take advice.
In the next few days i will install my new Mocal oil cooler kit, and the oil temp gauge at the same time. I think that from that point and after you will be totally right, i will have to move to a thinner oil since the temp will be under control.
 
Originally Posted By: jrustles
MINick, not sure what you're asking, so I will just illustrate the regulator and it's parts:

xf2r9v.jpg


The red arrow is parallel to the pressure regulator assembly and illustrates it's movement.
#6 is the piston which is acted upon by gross oil pressure.
#7 is the spring that determines the regulated pressure
#8&9 looks like a bushing a shim
#10 is the retainer clip that holds all of the above in the green circled area.

Some people change the spring (#7) to a higher tension spring or put a thicker shim (#9) to achieve a higher regulated oil pressure. This is commonly how most pumps are modified. The only other modification is to increase the displacement of the gerotor (#2&3) with a wider set, for a higher volume. I rarely find the need for a higher volume pump unless your delivery side leakage is increased (via larger clearances or thinner oil).

The further down the bore that #6 is pushed, the greater the pressure bleed off. I guestimate that the volume of high viscosity oil entering the pump at high RPM is unable to flow out on the delivery side nearly as fast as a thinner oil can, and all the excess volume (which is directly correlated to engine speed) has no where to go but the regulator, which may be being pushed down into it's most open position. (just a guess)

I hope that answers at least one of your questions!



Thanks a lot, i know the oil pump components, i just don't know if it's a bypass valve that will start bypassing oil at a given pressure, or a regulative valve, so i linked the pic in case you can tell.

When i built the engine, i tried to source wider gerotors from other pumps that could possibly fit, but found nothing unfortunately, and there's nothing available in the tuning market. I would possibly have wider gerotors made, but then comes the real hard stuff, to widen the case..
 
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It should be noted that modifying the by-pass valve to increase maximum OP is usually only done to avoid the going into by-pass mode with a given (heavy) oil viscosity which would otherwise reduces oil flow.
Since that is not the case here, it's not something I'd consider doing. Oil pressure itself does not aid in lubrication per se, as long as sufficient oil is being delivered to every part of the engine, although it can aid in keeping parts of the engine such as the bearings at a design maximum temperature.
That said I would think that 60 psi at maximum rev's is more than enough to provide adequate oil flow.
There are many much more powerful engines that do just fine with maximum OP of just 50 psi.
 
Originally Posted By: OVERKILL
Originally Posted By: Clevy
You gained oil pressure by reducing volume of flow.
First off you need to determine max oil temp when driving hard. Then take that temp and look up minimum oil pressure at max temp/rpm.
Now find an oil that will maintain the oil pressure at the max oil temp. That insures adequate pressure and viscosity when the oil is at its hottest.
Then use the thinnest oil you can find that meets your minimum pressure at maximum oil temp.
There is less parasitic loss with thinner oils which means more power to the wheels. Add that to thinner oils allow more volume per pump stroke which means more heat than be removed from the engine faster.
Thin as possible.
As thick as necessary.


A positive displacement oil pump displaces the same amount of oil per revolution if it is TGMO 0w-20 or TWS 10w-60. The volume is constant at a given RPM. Whether some of that oil goes out the bypass or all of it is forced through the engine is determined by the bypass pressure on the release valve. The pressure observed on the gauge is simply indicative as to the level of restriction in the system. And can tell you if the bypass is open or not.

That's true in theory but in practice heavier oil does flow at a reduced rate, even below the by-pass point, than lighter oil particularly when you're comparing a large viscosity difference such as between a 20wt and 60wt oil.

This was discussed in another thread a year or so ago and I don't remember all the technical reasons why but they included oil pump leakage, pick-up pipe diameter and screen size etc.
 
Guys, apart from the talk about the oil pump vs oil voscosity, is there anyone else using this oil? Or i will be the first to send a sample for testing? If i am the first, that means that i have to send a sample of new unused oil as well? (Blackstone)

Oh something about the bypass point. No matter what oil i use, i always see a decrease in OP as the oil "wears". Now, after 3-4k miles of use, the OP already decreased a bit. I also think that this is an indication that the valve is a bypass and not a regulator
 
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The decrease in OP as the oil "wears" is a combination of oil shear and fuel dilution.

We're not familiar with this exact Motul oil, it doesn't appear to be imported to NA. It's always great to have a VOA to compare to the PDS info'. You already know the oil shears to some extent in service so a UOA including a KV40, KV100 and TBN should provide all the info' you should want.
 
Yes, there's definately some shear/fuel dillution. We'll see to what extend soon
smile.gif
If the oil becomes a 40 after some use, i will probably not change to a thinner one
 
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Originally Posted By: CATERHAM
Originally Posted By: OVERKILL
Originally Posted By: Clevy
You gained oil pressure by reducing volume of flow.
First off you need to determine max oil temp when driving hard. Then take that temp and look up minimum oil pressure at max temp/rpm.
Now find an oil that will maintain the oil pressure at the max oil temp. That insures adequate pressure and viscosity when the oil is at its hottest.
Then use the thinnest oil you can find that meets your minimum pressure at maximum oil temp.
There is less parasitic loss with thinner oils which means more power to the wheels. Add that to thinner oils allow more volume per pump stroke which means more heat than be removed from the engine faster.
Thin as possible.
As thick as necessary.


A positive displacement oil pump displaces the same amount of oil per revolution if it is TGMO 0w-20 or TWS 10w-60. The volume is constant at a given RPM. Whether some of that oil goes out the bypass or all of it is forced through the engine is determined by the bypass pressure on the release valve. The pressure observed on the gauge is simply indicative as to the level of restriction in the system. And can tell you if the bypass is open or not.

That's true in theory but in practice heavier oil does flow at a reduced rate, even below the by-pass point, than lighter oil particularly when you're comparing a large viscosity difference such as between a 20wt and 60wt oil.

This was discussed in another thread a year or so ago and I don't remember all the technical reasons why but they included oil pump leakage, pick-up pipe diameter and screen size etc.


Got that bass ackwards again...

Thinner oils have more internal leakage, and displace less oil per revolution...unless you are hanging your hat on oil pump starvation, which isn't simply a change in viscosity.
 
The more you analyze, the more confused i get...
So, with a positive displacement pump, thicker oil is better to use as long as you don't go in bypass because there is less internal leakage.
So the only disadvantage in using a thicker oil, is the pumping loss?
 
Originally Posted By: CATERHAM
Originally Posted By: OVERKILL
Originally Posted By: Clevy
You gained oil pressure by reducing volume of flow.
First off you need to determine max oil temp when driving hard. Then take that temp and look up minimum oil pressure at max temp/rpm.
Now find an oil that will maintain the oil pressure at the max oil temp. That insures adequate pressure and viscosity when the oil is at its hottest.
Then use the thinnest oil you can find that meets your minimum pressure at maximum oil temp.
There is less parasitic loss with thinner oils which means more power to the wheels. Add that to thinner oils allow more volume per pump stroke which means more heat than be removed from the engine faster.
Thin as possible.
As thick as necessary.


A positive displacement oil pump displaces the same amount of oil per revolution if it is TGMO 0w-20 or TWS 10w-60. The volume is constant at a given RPM. Whether some of that oil goes out the bypass or all of it is forced through the engine is determined by the bypass pressure on the release valve. The pressure observed on the gauge is simply indicative as to the level of restriction in the system. And can tell you if the bypass is open or not.

That's true in theory but in practice heavier oil does flow at a reduced rate, even below the by-pass point, than lighter oil particularly when you're comparing a large viscosity difference such as between a 20wt and 60wt oil.

This was discussed in another thread a year or so ago and I don't remember all the technical reasons why but they included oil pump leakage, pick-up pipe diameter and screen size etc.


I would think you'd get greater leakage with a thinner oil than a thicker one....
21.gif


If pick-up tube diameter and the like plays a role, then engine design, oil pump displacement volume per rotation, pick-up size...etc all play a role too. Which would mean that this varies by application.
 
Originally Posted By: Shannow
Originally Posted By: CATERHAM
Originally Posted By: OVERKILL
Originally Posted By: Clevy
You gained oil pressure by reducing volume of flow.
First off you need to determine max oil temp when driving hard. Then take that temp and look up minimum oil pressure at max temp/rpm.
Now find an oil that will maintain the oil pressure at the max oil temp. That insures adequate pressure and viscosity when the oil is at its hottest.
Then use the thinnest oil you can find that meets your minimum pressure at maximum oil temp.
There is less parasitic loss with thinner oils which means more power to the wheels. Add that to thinner oils allow more volume per pump stroke which means more heat than be removed from the engine faster.
Thin as possible.
As thick as necessary.


A positive displacement oil pump displaces the same amount of oil per revolution if it is TGMO 0w-20 or TWS 10w-60. The volume is constant at a given RPM. Whether some of that oil goes out the bypass or all of it is forced through the engine is determined by the bypass pressure on the release valve. The pressure observed on the gauge is simply indicative as to the level of restriction in the system. And can tell you if the bypass is open or not.

That's true in theory but in practice heavier oil does flow at a reduced rate, even below the by-pass point, than lighter oil particularly when you're comparing a large viscosity difference such as between a 20wt and 60wt oil.

This was discussed in another thread a year or so ago and I don't remember all the technical reasons why but they included oil pump leakage, pick-up pipe diameter and screen size etc.


Got that bass ackwards again...

Thinner oils have more internal leakage, and displace less oil per revolution...unless you are hanging your hat on oil pump starvation, which isn't simply a change in viscosity.


That's how I thought about it too Shannow. That a thinner oil is going to leak by the gears more and result in less flow unless the pump is in bypass.
 
Originally Posted By: MINick
The more you analyze, the more confused i get...
So, with a positive displacement pump, thicker oil is better to use as long as you don't go in bypass because there is less internal leakage.
So the only disadvantage in using a thicker oil, is the pumping loss?


Well, there's always cavitation too, LOL!
 
Originally Posted By: MINick

Thanks a lot, i know the oil pump components, i just don't know if it's a bypass valve that will start bypassing oil at a given pressure, or a regulative valve, so i linked the pic in case you can tell.

When i built the engine, i tried to source wider gerotors from other pumps that could possibly fit, but found nothing unfortunately, and there's nothing available in the tuning market. I would possibly have wider gerotors made, but then comes the real hard stuff, to widen the case..


Ah haha, so you know what you're doing, sorry for wasting all of our time. Had I only clicked the link
happy2.gif
Well hopefully someone got something out of it.

Anyway, in the parts list, it's termed "Control Valve", because it controls pressure and happens to do that by bypassing oil. It's a "bypass regulator" that begins to operate at a certain point. That point, is not as high as one may imagine. Therefore bypass as a "mode" is almost always happening. Just imagine 2000cSt cold oil vs 10cSt hot oil and you never see more than 70-80psi(eg) on the gauge. The valve obviously needs a wide ranging orifice (regulative capacity). The valve begins opening as pressure builds on the gauge- for example 3K+ at full hot rec. viscosity. Anything colder * anything thicker, and that baby is open, even if a little bit. The maximum pressure you see is not the magic opening point, because that changes with actually viscosity. Many times some oil pumps can put out pressures higher than their design pressure due to an inadequate bypass channel, and a person may be led to believe that this is their bypass pressure when that bad boy started opening up long ago. But some people like 100+psi cold on their gauge.

Internal leakage, cavitation all good considerations.

Shan's, too right that a thinner oil would leak internally more. How much more? Anyone wanna to calculate this using pump displacement and measuring output volume? An equal increase in leakage on the delivery side might help balance that out
wink.gif



MINick, you should examine the control valve bore on your oil pump, I noticed it's stepped, three times, is there a secondary bypass channel?
 
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