4 - Ball Wear of Mobil's 4XT
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Thanks for the great info guys!
On camshafts I've always understood (right or wrong) that one of the lubrication "problems" is that they only turn 1/2 engine speed. The idea being it takes a certain amount speed to surf on the oil. Aprox 1000 rpm is what Crane cams advised me many years ago. That means the engine needs to be turning 2000 rpm, any less and the AW add in the oil really comes into play. Of course oil viscosity, valve spring tension, valve lift acceleration etc probably comes into play on the actaul rpm. This was the reasoning for new cam prelube and the bottle of oil suppliment they sent out with there cams (looked like moly?). Also the advise to start a new motor and get it above 2000, don't let it idle.
When overdrive autos became common in V8 autos cruising under 2000rpms for long times was normal. Cam profiles that allow the use of real light valve springs with slow opening and closing ramps were developed to slow cam wear. These cams were not exactly what you'd call performance grinds. One way the oems' have got around this is the use of roller lifters.
On camshafts I've always understood (right or wrong) that one of the lubrication "problems" is that they only turn 1/2 engine speed. The idea being it takes a certain amount speed to surf on the oil. Aprox 1000 rpm is what Crane cams advised me many years ago. That means the engine needs to be turning 2000 rpm, any less and the AW add in the oil really comes into play. Of course oil viscosity, valve spring tension, valve lift acceleration etc probably comes into play on the actaul rpm. This was the reasoning for new cam prelube and the bottle of oil suppliment they sent out with there cams (looked like moly?). Also the advise to start a new motor and get it above 2000, don't let it idle.
When overdrive autos became common in V8 autos cruising under 2000rpms for long times was normal. Cam profiles that allow the use of real light valve springs with slow opening and closing ramps were developed to slow cam wear. These cams were not exactly what you'd call performance grinds. One way the oems' have got around this is the use of roller lifters.
Buster,
No one is arguing the validity of engine sequence tests....
However that is way too much data (TMI) for the average end user of synthetics to internalize and understand. To be brutally honest, you have to DUMB DOWN the advertising message to get folks to understand the superiority of synthetic lubricants....I even have to do it and 90% of my local customer are Aerospace engineers, many of whom have advanced degrees. You would not believe how few of them understand the concept of an SAE 0w-30 oil....That's one of the main reasons I started selling the 5w-30, S3000 product in its' place.
To quote crazy Jack: "You want the truth, you can't handle the truth!"
No one is arguing the validity of engine sequence tests....
However that is way too much data (TMI) for the average end user of synthetics to internalize and understand. To be brutally honest, you have to DUMB DOWN the advertising message to get folks to understand the superiority of synthetic lubricants....I even have to do it and 90% of my local customer are Aerospace engineers, many of whom have advanced degrees. You would not believe how few of them understand the concept of an SAE 0w-30 oil....That's one of the main reasons I started selling the 5w-30, S3000 product in its' place.
To quote crazy Jack: "You want the truth, you can't handle the truth!"
Wiley,
You do develop thicker oil films in the valvetrain at higher rpms....
To understand this concept think of "squeeging" water off your windshield. If you wipe slowly the water (oil) has a chance to run off both edges of the squeege (or nose of the cam lobe if you will). However if you pull the squeege very rapidly across the surface, a dam of water builds up across the face, since the water can't escape fast enough. The geometry of a cam lobe and valve lifter functions in much the same way.
It's been very difficult for me to come up with a simple analogy to get people to understand this concept. I hope this helps ....Note also that liquids are essentially incompressible, which also factors into the physics of this situation.
Note that the localized viscosity of the oil wedge at the nose of the cam lobe can be hundreds of times higher than it would be in an unconstrained situation....It basically acts as a solid under these conditions and elastically (Ref: Hookes Law) deforms the top of the valve lifter.
Ted
You do develop thicker oil films in the valvetrain at higher rpms....
To understand this concept think of "squeeging" water off your windshield. If you wipe slowly the water (oil) has a chance to run off both edges of the squeege (or nose of the cam lobe if you will). However if you pull the squeege very rapidly across the surface, a dam of water builds up across the face, since the water can't escape fast enough. The geometry of a cam lobe and valve lifter functions in much the same way.
It's been very difficult for me to come up with a simple analogy to get people to understand this concept. I hope this helps ....Note also that liquids are essentially incompressible, which also factors into the physics of this situation.
Note that the localized viscosity of the oil wedge at the nose of the cam lobe can be hundreds of times higher than it would be in an unconstrained situation....It basically acts as a solid under these conditions and elastically (Ref: Hookes Law) deforms the top of the valve lifter.
Ted
I won't argue wiht a NASA engineer.
Ted your right. My issue with it, was just oil oil A that has a .39mm wear scara vs B .69mm won't result in less wear in a gas engine. I do believe like you said the 4-Ball wear test does test a certain aspect of an oil. Whether this translates over into engines I do not believe and can be misleading thats all.
Hi,
Ted - in an earlier post you said this;
"The Four Ball Wear test is used to evaluate the gear protection afforded by auto transmission fluids and gear lubricants."
You responded to my question about "who and what" by quoting Mercon V
What about all of the Manufacturer's I mentioned?
And as for valve train wear, the worst offenders are probably the heavy diesel engines of Cummins, CAT and Detroit. They all recommend a conforming but typical HDEO of 15w-40 viscosity. No 4 ball tests required on these Ted!
Regards
Doug
Ted - in an earlier post you said this;
"The Four Ball Wear test is used to evaluate the gear protection afforded by auto transmission fluids and gear lubricants."
You responded to my question about "who and what" by quoting Mercon V
What about all of the Manufacturer's I mentioned?
And as for valve train wear, the worst offenders are probably the heavy diesel engines of Cummins, CAT and Detroit. They all recommend a conforming but typical HDEO of 15w-40 viscosity. No 4 ball tests required on these Ted!
Regards
Doug
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I subscribe to that claim. It suggest that there is truth to the claim that cam wear is higher at idle than under any other engine operating condition. It also supports the theory that long cam life, at least in some motors (like certain BMW engines!), is helped by a high-RPM driving style.
I would have to argue that "Show me any test that has any relevance in an operating engine" using this mindset. The key word is "test" here. The real "test" is "Does it perform well in my engine?" - Regardless of what the "tests" say!quote:
Originally posted by buster:
You must sell Amsoil bc it's propaganda.Show me proof that the 4-Ball wear test has any meaing in ENGINE OIL. It's not relevant to oil, but it is to grease.
Back to the Mobil MX4T, I'm surprised no one is using this oil in lawn and garden equipment. I know it's expensive, but my guess is that it was designed for the temperatures seen in most small air cooled engines, not just motorcycles.
I'd think the 10W-40 would be perfect for this type of equipment...
I'd think the 10W-40 would be perfect for this type of equipment...
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