Needle thrust bearing suitability

[GT6Steve]

Greetings,
Would someone please comment on the suitability of a needle thrust bearing and washer assembly replacing a damaged thrust bushing in a high RPM internal combustion engine. I envision machining a new thrust face at the front of the block and stacking the components (Torrington FNTA6085) over the nose of the crank on assembly.
This would be splash lubricated with 240F synthetic oil.
I'm concerned with the accleration the needles would face when the clutch is pressed, essentialling going from static to 8000 RPM.
Is this an appropriate application and will splash oiling be adequate for the intermittent loads and accleration?
Thanx in advance, Steve

 

[electricpete]

The only needle bearings I have heard of are radial bearings.

Guess there's a lot I haven't heard of.

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[GT6Steve]

OK, so is the question too vague, the application too strange or is there just no experience on this list with thrust bearings? This seems to me to be a very straight forward application, a high RPM usage of a common! thrust bearing. Why the reticence? There's no attorney watching from my team)

I got this same stonewall from Torrington so I assume there are some questions as to suitability and hence liability.

I guess I'll do the American thing and experiment and test and measure and document and when I'm all done some Suit will say, we knew that,,,,Jeez

 

[unclesyd]

I was going to point you in a direction to where enough information is available that might be of some help, but you reply dictated otherwise

I believe with your attitude that experimentation might be your best track. What’s one or two clutches and trannies or maybe a crank or two. If you will read the hotrod/dragster mags a little closer you should pickup a little information to help with your experiments

 

[israelkk]

GT6Steve

I would go with calculations before testing. The bearing catalog should have the info for the maximum rotation speed, dynamic load and temperatures allowed for these type of thrust bearings. If it is not in the catalog the manufacturer should have the data.

However, before testing, calculations must be made unless time and money are not a problem. There is a reason why crankshafts use bushings, it is a result of many years of experience. Bushings can hold higher loads at the same space and they use the hydrodynamic effect of the fluid as the bearing. When the bushing is at the rated speed the crackshaft is actally floating and there is no metal to metal contact.

All the wear is at start and stop (when speed cproaches zero) or when lubrication is failing or poorly designed.

 

[GT6Steve]

Thanx IsraelKK,
I agree that bushings have won the application because they're the most suitable. It will be oilite 821 going back in. As UncleSyd points out, these things do cost money.
That said, I'd still like to see the load data for these bearings as none of our catalogs and manuals list more than dimensions, hence the plea to the professionals.

 

[unclesyd]

Perseverance:

Here is a site that I had in mind for additional information with more load data. We used Axial thrust needle bearings in an extruder system with fairly high loads but with considerably lower speed and a flooded lube enviroment. We changed to a cylindrical roller, thicker, thrust bearing system to better handle the load, much higher than we had figured. You will need a very hard surface for the needle bearings unless you have hardened face washers.
There had been considerable work in this area by the transmission people, but from my reading they have mixed results in this area.

This site is a little hard to navigate bu has very good info.

http://www.ina.com/inaupdate/index.asp?l=en

 

[GT6Steve]

Thank You UncleSyd,

Let me apologize for the tone of my post. Funny thing, I wasn't even upset until I thought of liability issues perhaps inhibiting Torrington from responding and then the attorneys made me mad. Sorry.

I had intended to use the hardened thrust faces along with the needles. I simply haven't seen any data on these bearings and don't even know yet what a rated surface speed is for them. With that I can do some calcs and get a sound idea of the application.

It's relegated to the theoretical realm now however as I was able to save the thrust face on the crankshaft and will be fabricating a thicker thrust bushing for all the reasons IsraelKK mentioned.

Thanks for the link...Steve

 

[unclesyd]

GT6Steve,

Have been there and done that also so no problem.

As I stated the site is little hard to navigate but their bearing calculator seems to work very well. I gave all my bearing literature away but I remember a booklet I believe by FAG that had section on needle thrust bearings. If I can find any reference to it I'll post it.

unclesyd

 

[electricpete]

I hope you guys will bear with me on a basic question about "needle thrust bearings"?

Is the axis of the needle parallel to the shaft or perpendicular to the shaft?

If parallel to the shaft, how does it take thrust?

If perpendicular to the shaft, how do we account for the fact that the outside of the needle needs to travel farther/faster than the inside of the needle.

If angle to the shaft, same problem as perpendicular to the shaft...would need taper roller bearings vs needle.

Thx.

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[Tmoose]

They can have cylindrical needles perpendicular to the shaft.

http://www.nrb.com.cn/cp/img/tui.jpg

http://www.tsimportedautomotive.com/nbk.JPG

Their speed is limited in part by the sliding resulting from the speed differential from end to end. My 1950 chevy transmission had thrust washers at either end of the always spinning-but-rarely-loaded reverse idler gear. It had worn the iron trans case and itself into mush, as had every other old trans case I looked at. I machined the case for a needle thrust bearing, just like the "new" 1955 transmission would have had.
That type bearing was considered a heavy duty upgrade for Chevy V-8s at one time.

The clutch loads push the crank forward. I'm not sure how a needle bearing could be slipped on the crank nose to handle those loads, even if the speed/clearance was not a problem.

 

[GT6Steve]

That speed differential is one of the factors making this application questionable. Very interesting comment about wearing the case on the transmission. Presumably the washers would rotate because of the light load. An issue I hadn't considered. I know Mazda uses these bearings with the washers in their engines but I've no idea of their loads.

Mechanically, assembling the thrust washers onto the crankshaft is easy with only a bit of machine work to true up the surfaces behind the front main cap required. It's the suitability that makes it awkward.
Steve

 

[israelkk]

In the following file from Torrington page 482 for example you can the limiting speed for needle thrust bearings. The larger the bearing diamter the lower speed limit.

http://www.timken.com/industries/torrington/catalog/pdf/needle/n_thrust.pdf

 

[GT6Steve]

Thank You Immensely IsraelKK!
That was the resource I needed. 4900 is the maximum RPM for my proposed dimension which is a touch over one half the required RPM. It's just knowing where to look;-). Steve

 

[blfarrar]

Needle rollers are not that suitable for high speed applications, consider the rollers have to take on the rotational speed casued when under load & rotational speed of assembly.

The needles being small have to rotate very fast, which is something they are incapable of doing.
Needle rollers are an alternative to bushings of brass, P/Bronze, W/Metal (Babbit) etc.

Not very good if you get contaminated lubrication, especially bad if there is any water in the oil as the cages are mostly ferrous & rust away rapidly. If they lock on an impact they disintegrate with alarming results - hardened needle rollers everwhere - they can cause untold damage especially in gear transmissions & oil pumps.

If I can visualise what you are building or replacing - the elegant solution is a white metal thrust bearing with oil grooves.