Start up rattle
03-06-2007, 11:06 PM
#31
Burning Brakes
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Hi,
I have assumed (I hope correctly) that we are talking about "valve train" noise here. All noises first need to be carefully diagnosed of course!
Some valve train noise is due to the metallurgy and actuators used in modern valve trains (and elsewhere). As long as the noise disappears within a short time (say 30seconds) it is harmless and a factor of the engine/lubricant characteristics. Late model BMW owners know all about the phenomenon!
Some oils are less acoustically "absorbent" than others too. Various M1 lubricants can be noisier than certain other Brands at startup but THIS HAS NOTHING TO DO WITH ENGINE WEAR!!!
It has a lot to do with the base lubricant(s), its pour point and the additive package used!
Brant - you are correct the "flow" of a 15w-50 viscosity lubricant and a 0w-40 viscosity lubricant will indeed be VERY different at 20f (-7C). Well, that is if we firstly rationalise a few things;
a) Is the 15w-50 lubricant a mineral or synthetic? (The 0w-40 will be a synthetic!) This would make a significant difference!
b) The Brands and Models of the lubricant will tell the story! Similar specification lubricants do not always produce the same results as they warm up!
c) We must assume that by using the word "flow" you mean the ability of the lubricant to arrive at its desired location in sufficient volume to do its job!
This is because the oil pump's output (volume) is constant per revolution - engine oil pumps are of a constant displacement as we all know!
The respective viscosity estimates of M1 at 20f (-7C) are;
15w-50 (EP) - 1292cSt
0w-40 - 530cSt
This is a significant variance!!!
Understanding how these two lubricants will circulate and lubricate an engine at 20f (-7C) is not too difficult. The non Approved 15w-50 lubricant is almost 2.5 times more viscous (thicker) than the Approved 0w-40! Imagine this lubricant trying to enter and leave restricted valve train components and elsewhere as the revs climb! Normally up to 25% of overall engine friction comes from the valve train area - increased viscous drag in this area can cause increased loads on cam lobes. Increased "stiffness" is certainly a design consideration as far as wear factors are concerned
At 20f (-7C) the more viscous lubricant (15w-50) will likely exit significant volume via the system's by-pass. It is unlikely to be flowing through the filter's media either as it will be in some position of differential by-pass at this temperature. Some non OEM filters stay longer in by pass but normally it can occur up to and beyond an oil temperature of around >70C.
Even with synthetic filtration media such as Donaldson's excellent "Synteq" this can occur until the oil's temperature is >40C or so
The less viscous lubricant (0w-40 synthetic) will most likely not trigger the lubrication system's by-pass very much at this point
1999Porsche911 - as usual you appear to be a little "lost" in the realms of engine lubrication and lubricants. Both viscosity lubricants will "flow" the same from the oil pump - its just a matter of where the oil ends up!!
Also, at an engine "close down" core temperature at say a 100C (212f), both lubricants will drain away at nearly the SAME flow rates! If the engine's shut down was at 20f (-7C) core temperature, the situation would simply be that the more viscous lubricant would "hang around" longer. The end result for the engine's wear rates would still be the SAME!
The "oil film" left behind has very little to do with the fluid "carrier" (the lubricant) - it has a lot to do with the chemical structures within the lubricant's formulation!!
The API and ACEA quality rating processes call for minimum standards in this regard to ensure a known wear rate at start up
Typically the chemical barriers are all much the same in modern additive packages but you get what you pay for! The more you pay for a lubricant the more you get in general terms!!
Regards
I have assumed (I hope correctly) that we are talking about "valve train" noise here. All noises first need to be carefully diagnosed of course!
Some valve train noise is due to the metallurgy and actuators used in modern valve trains (and elsewhere). As long as the noise disappears within a short time (say 30seconds) it is harmless and a factor of the engine/lubricant characteristics. Late model BMW owners know all about the phenomenon!
Some oils are less acoustically "absorbent" than others too. Various M1 lubricants can be noisier than certain other Brands at startup but THIS HAS NOTHING TO DO WITH ENGINE WEAR!!!
It has a lot to do with the base lubricant(s), its pour point and the additive package used!
Brant - you are correct the "flow" of a 15w-50 viscosity lubricant and a 0w-40 viscosity lubricant will indeed be VERY different at 20f (-7C). Well, that is if we firstly rationalise a few things;
a) Is the 15w-50 lubricant a mineral or synthetic? (The 0w-40 will be a synthetic!) This would make a significant difference!
b) The Brands and Models of the lubricant will tell the story! Similar specification lubricants do not always produce the same results as they warm up!
c) We must assume that by using the word "flow" you mean the ability of the lubricant to arrive at its desired location in sufficient volume to do its job!
This is because the oil pump's output (volume) is constant per revolution - engine oil pumps are of a constant displacement as we all know!
The respective viscosity estimates of M1 at 20f (-7C) are;
15w-50 (EP) - 1292cSt
0w-40 - 530cSt
This is a significant variance!!!
Understanding how these two lubricants will circulate and lubricate an engine at 20f (-7C) is not too difficult. The non Approved 15w-50 lubricant is almost 2.5 times more viscous (thicker) than the Approved 0w-40! Imagine this lubricant trying to enter and leave restricted valve train components and elsewhere as the revs climb! Normally up to 25% of overall engine friction comes from the valve train area - increased viscous drag in this area can cause increased loads on cam lobes. Increased "stiffness" is certainly a design consideration as far as wear factors are concerned
At 20f (-7C) the more viscous lubricant (15w-50) will likely exit significant volume via the system's by-pass. It is unlikely to be flowing through the filter's media either as it will be in some position of differential by-pass at this temperature. Some non OEM filters stay longer in by pass but normally it can occur up to and beyond an oil temperature of around >70C.
Even with synthetic filtration media such as Donaldson's excellent "Synteq" this can occur until the oil's temperature is >40C or so
The less viscous lubricant (0w-40 synthetic) will most likely not trigger the lubrication system's by-pass very much at this point
1999Porsche911 - as usual you appear to be a little "lost" in the realms of engine lubrication and lubricants. Both viscosity lubricants will "flow" the same from the oil pump - its just a matter of where the oil ends up!!
Also, at an engine "close down" core temperature at say a 100C (212f), both lubricants will drain away at nearly the SAME flow rates! If the engine's shut down was at 20f (-7C) core temperature, the situation would simply be that the more viscous lubricant would "hang around" longer. The end result for the engine's wear rates would still be the SAME!
The "oil film" left behind has very little to do with the fluid "carrier" (the lubricant) - it has a lot to do with the chemical structures within the lubricant's formulation!!
The API and ACEA quality rating processes call for minimum standards in this regard to ensure a known wear rate at start up
Typically the chemical barriers are all much the same in modern additive packages but you get what you pay for! The more you pay for a lubricant the more you get in general terms!!
Regards
03-06-2007, 11:19 PM
#32
Nordschleife Master
Thread Starter
Thanks Doug for the indepth explanation. My main concern with the "rattle" was that the valves were not properly lubricated on start up and that this rattle (lasting approx. 2seconds) was creating excessive wear. I have not owned a car that has had this issue before but then again I have not had a car with an engined designed like this. Since your from a hot arid region do you recommend 0W-40? I wasn't aware that the 15W-50 was non-approved...
03-07-2007, 12:10 AM
#33
Burning Brakes
Join Date: Dec 2002
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Hello,
yes, it is a hot and arid place here - sometimes even in our Tropics region where I live on the edge of the Great Barrier Reef
Either a 0w-40 or 5w-40 viscosity lubricant from the Approvals List will do well for you. There are a number of lubricants from the List that can be purchased in NA
These are Approved:
Quaker State Full Synthetic Euro Formula 5w-40
Havoline Ultra 5w-40
Kendal GT1 Pure Synthetic Motor Oil 5w-40
Mobil 1 0w-40
The Mobil product has the most advanced formulation but they will all do the job. Of course they are all SAE40 lubricants
Sometimes valve gear noise can originate from using non OEM oil filters. it is always wise to use the OEM filter - their valving and filtering media are of first class quality
I use M1 0w-40 in my MY06 Supercharged CLK Benz - it is a little noisy at startup (for about 5secs) and I often operate it in an ambient up to 110f
Best wishes
yes, it is a hot and arid place here - sometimes even in our Tropics region where I live on the edge of the Great Barrier Reef
Either a 0w-40 or 5w-40 viscosity lubricant from the Approvals List will do well for you. There are a number of lubricants from the List that can be purchased in NA
These are Approved:
Quaker State Full Synthetic Euro Formula 5w-40
Havoline Ultra 5w-40
Kendal GT1 Pure Synthetic Motor Oil 5w-40
Mobil 1 0w-40
The Mobil product has the most advanced formulation but they will all do the job. Of course they are all SAE40 lubricants
Sometimes valve gear noise can originate from using non OEM oil filters. it is always wise to use the OEM filter - their valving and filtering media are of first class quality
I use M1 0w-40 in my MY06 Supercharged CLK Benz - it is a little noisy at startup (for about 5secs) and I often operate it in an ambient up to 110f
Best wishes
03-07-2007, 12:19 AM
#34
Technical Guru
Rennlist Member
Rennlist Member
Originally Posted by Doug Hillary
This is because the oil pump's output (volume) is constant per revolution - engine oil pumps are of a constant displacement as we all know!
He wouldn't say but I think they will OEM it from Kolbenschmidt Pierburg?
03-07-2007, 12:29 AM
#35
Burning Brakes
Join Date: Dec 2002
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Hi Jason,
thanks for the Info. these types of oil pumps will be a really great component offering many engine durabilty advantages
We can expect closed lubrication systems soon too - these will be a "Unit" with filter and possibly a centrifuge included - and maybe no facility to change the oil! Technology moves on!
Thank again Jason
Regards
thanks for the Info. these types of oil pumps will be a really great component offering many engine durabilty advantages
We can expect closed lubrication systems soon too - these will be a "Unit" with filter and possibly a centrifuge included - and maybe no facility to change the oil! Technology moves on!
Thank again Jason
Regards
03-07-2007, 10:25 AM
#37
Nordschleife Master
Thread Starter
Mfletch,
Yeah after I posted I looked around and found the thread. The first couple of pics were sore on the eyes, they gave me a shiver. But you certainly brought it back from the dead. Nice job!
Yeah after I posted I looked around and found the thread. The first couple of pics were sore on the eyes, they gave me a shiver. But you certainly brought it back from the dead. Nice job!
03-09-2007, 07:55 AM
#38
Three Wheelin'
Eharrison, Thanks it was a lot of fun. I'm just finishing up another project car that I brought back to life for my dad. It's an enjoyable addiction.
