more thoughts about needle bearings

[Geoff2]

It is an engineering fact that both ball & roller [ needle included ] require minimal lubrication, compared to a plain brg. I have often wondered if the much touted marketing hype of 'pressure fed' oiling of needle roller lifters is more detrimental than helpful.
Is it possible that in the confined space of the needle roller lifter, the needles are getting 'hydraulic lock' & it stops the needles rotating? That may not be the correct term but could there be so much oil that the needles are unable to rotate. It is a short step to destruction when a roller in a roller brg stops rotating....

[Warp Speed]

It is an engineering fact that both ball & roller [ needle included ] require minimal lubrication, compared to a plain brg. I have often wondered if the much touted marketing hype of 'pressure fed' oiling of needle roller lifters is more detrimental than helpful.
Is it possible that in the confined space of the needle roller lifter, the needles are getting 'hydraulic lock' & it stops the needles rotating? That may not be the correct term but could there be so much oil that the needles are unable to rotate. It is a short step to destruction when a roller in a roller brg stops rotating....

So you are saying a pressure fed roller bearing lifter is a bad thing huh?!?
And now may actually cause problems?!? Lol

[pamotorman]

chain saws with needle bearing connecting rods turning 10,000+ RPMs are lubed with a 100 :1 gasoline to oil mixture with no problems.

[nhrastocker]

Some of the comments are like shooting darts while being blindfolded.
Needle bearings have been in use since the 1930's.
They are designed for specific purposes and based on its final use, you need to select the appropriate bearing and material.
Needle bearings are manufactured with different material alloys based in their final use.
Needle bearings CAN and WILL take lots of loads and impact if you use the right needle bearing design.
Proper lubrication of a needle bearing is a must!
The same applies to any bearing design that will experience high loads and speeds.
Needle bearings will not experience hydraulic lock due to lubrication.
Bushings have a specific purpose, however, not for a lifter.
If you do a Mohr's Circle calculation for a bushed lifter, the results will show higher friction which will require more lubrication when compared to a needle bearing.

How do I know this? After 38 years in the aircraft industry as an engineer, bushings have been replaced by needle bearings on critical flight controls.
Bushings require more lubrication servicing than a needle bearing and show less wear than a bushing during service.

[Belgian1979]

Some of the comments are like shooting darts while being blindfolded.
Needle bearings have been in use since the 1930's.
They are designed for specific purposes and based on its final use, you need to select the appropriate bearing and material.
Needle bearings are manufactured with different material alloys based in their final use.
Needle bearings CAN and WILL take lots of loads and impact if you use the right needle bearing design.
Proper lubrication of a needle bearing is a must!
The same applies to any bearing design that will experience high loads and speeds.
Needle bearings will not experience hydraulic lock due to lubrication.
Bushings have a specific purpose, however, not for a lifter.
If you do a Mohr's Circle calculation for a bushed lifter, the results will show higher friction which will require more lubrication when compared to a needle bearing.

How do I know this? After 38 years in the aircraft industry as an engineer, bushings have been replaced by needle bearings on critical flight controls.
Bushings require more lubrication servicing than a needle bearing and show less wear than a bushing during service.

Thanks, but this still begs the question, why do we apparently have more reports of needle bearing lifter going bust than bushings ? Shock loads ?

[pamotorman]

Some of the comments are like shooting darts while being blindfolded.
Needle bearings have been in use since the 1930's.
They are designed for specific purposes and based on its final use, you need to select the appropriate bearing and material.
Needle bearings are manufactured with different material alloys based in their final use.
Needle bearings CAN and WILL take lots of loads and impact if you use the right needle bearing design.
Proper lubrication of a needle bearing is a must!
The same applies to any bearing design that will experience high loads and speeds.
Needle bearings will not experience hydraulic lock due to lubrication.
Bushings have a specific purpose, however, not for a lifter.
If you do a Mohr's Circle calculation for a bushed lifter, the results will show higher friction which will require more lubrication when compared to a needle bearing.

How do I know this? After 38 years in the aircraft industry as an engineer, bushings have been replaced by needle bearings on critical flight controls.
Bushings require more lubrication servicing than a needle bearing and show less wear than a bushing during service.

Thanks, but this still begs the question, why do we apparently have more reports of needle bearing lifter going bust than bushings ? Shock loads ?

my guess is they are too small for the load they bear but there is no room for larger ones

[Old as Dirt]

chain saws with needle bearing connecting rods turning 10,000+ RPMs are lubed with a 100 :1 gasoline to oil mixture with no problems.

Same as our 100cc Italian rotary 2 strokes.. but between 17,000 and 21,000... on alcohol w/ 6oz's per gallon of Blendzall

Velocity 2003.jpg

[pamotorman]

chain saws with needle bearing connecting rods turning 10,000+ RPMs are lubed with a 100 :1 gasoline to oil mixture with no problems.

Same as our 100cc Italian rotary 2 strokes.. but between 17,000 and 21,000... on alcohol w/ 6oz's per gallon of Blendzall
Velocity 2003.jpg

are those caged or lose bearings in the rod ??

[Old as Dirt]

Caged..

[Belgian1979]

Some of the comments are like shooting darts while being blindfolded.
Needle bearings have been in use since the 1930's.
They are designed for specific purposes and based on its final use, you need to select the appropriate bearing and material.
Needle bearings are manufactured with different material alloys based in their final use.
Needle bearings CAN and WILL take lots of loads and impact if you use the right needle bearing design.
Proper lubrication of a needle bearing is a must!
The same applies to any bearing design that will experience high loads and speeds.
Needle bearings will not experience hydraulic lock due to lubrication.
Bushings have a specific purpose, however, not for a lifter.
If you do a Mohr's Circle calculation for a bushed lifter, the results will show higher friction which will require more lubrication when compared to a needle bearing.

How do I know this? After 38 years in the aircraft industry as an engineer, bushings have been replaced by needle bearings on critical flight controls.
Bushings require more lubrication servicing than a needle bearing and show less wear than a bushing during service.

Thanks, but this still begs the question, why do we apparently have more reports of needle bearing lifter going bust than bushings ? Shock loads ?

my guess is they are too small for the load they bear but there is no room for larger ones

Load is always spread over the contact area. In case of a needle you always only have a limited contact zone. In fact it is only a line. The only way to increase the load bearing surface would be to have more needles acting on the same axle.
I do know one thing that will always kill a needle bearing and that is a shock load. Smash something with enough force into an equally hard surface and you will get an indentation. That indentation will cause vibrations and will hammer the needles and eventually destroy them.

[pamotorman]

Thanks, but this still begs the question, why do we apparently have more reports of needle bearing lifter going bust than bushings ? Shock loads ?

my guess is they are too small for the load they bear but there is no room for larger ones

Load is always spread over the contact area. In case of a needle you always only have a limited contact zone. In fact it is only a line. The only way to increase the load bearing surface would be to have more needles acting on the same axle.
I do know one thing that will always kill a needle bearing and that is a shock load. Smash something with enough force into an equally hard surface and you will get an indentation. That indentation will cause vibrations and will hammer the needles and eventually destroy them.

that is why I like a rev kit to keep the roller in contact with the cam lobe 100% of the time.

[MadBill]

...I do know one thing that will always kill a needle bearing and that is a shock load. Smash something with enough force into an equally hard surface and you will get an indentation. That indentation will cause vibrations and will hammer the needles and eventually destroy them.

Quite so!
https://en.wikipedia.org/wiki/Brinelling

[GARY C]

...I do know one thing that will always kill a needle bearing and that is a shock load. Smash something with enough force into an equally hard surface and you will get an indentation. That indentation will cause vibrations and will hammer the needles and eventually destroy them.

Quite so!
https://en.wikipedia.org/wiki/Brinelling

It seems like that would have more of an effect on the rocker arm considering all the mass and force at valve closing is driving the lifter downwards towards the cam and at base circle your rocker leaves the valve tip by the amount you set your valve lash only to be slammed back against the valve by the opening lash ramp.

I don't think I have ever seen a solid flat or roller that doesn't show a constant pattern around the base circle, for the lifter to be beat on it would actually require the lifter to actually jump up off of the base circle, this is why I question the advantage of a rev kit with the exception of keeping the lifter in the bore if you break a p rod or rocker.

[pamotorman]

...I do know one thing that will always kill a needle bearing and that is a shock load. Smash something with enough force into an equally hard surface and you will get an indentation. That indentation will cause vibrations and will hammer the needles and eventually destroy them.

Quite so!
https://en.wikipedia.org/wiki/Brinelling

It seems like that would have more of an effect on the rocker arm considering all the mass and force at valve closing is driving the lifter downwards towards the cam and at base circle your rocker leaves the valve tip by the amount you set your valve lash only to be slammed back against the valve by the opening lash ramp.

I don't think I have ever seen a solid flat or roller that doesn't show a constant pattern around the base circle, for the lifter to be beat on it would actually require the lifter to actually jump up off of the base circle, this is why I question the advantage of a rev kit with the exception of keeping the lifter in the bore if you break a p rod or rocker.

there is the lash setting that could allow the lifter to float free of the lobe at high RPMs.

[user-23911]

Take a good look at a factory designed needle roller setup and you'll find in the case of DOHC and needle roller finger followers, hydraulic lash adjusters are used to keep everything in contact at all times. That reduces shock loadings of the needles so that they'll outlast the rest of the engine if maintained properly.
Same goes for a similar setup but built for more RPM, mechanical lash adjustment but still needle rollers running on the cam lobes. In this case there's extra springs on the rockers to keep the rollers on the cams when on the base circle.
Factory reliability of course. Proven technology by winning the Paris Dakkar many times.