18 replies to this topic

[NeilR]

I'm curious about gear lubrication in a Torsen T2 diff, which is at the end of the day a friction device.
Now Quaife and others sell their T2 Torsen diffs and recommend a specific oil lubrication...yet in the quaife's chain drive diff (which is a Fiesta diff in a can) they use HP grease. Would the change in lubrication feasibly alter the bias ratio? Any downsides to using grease?

[cheapracer]

IMO - I presume it's a helical gear type so presume they use a heavier grease to offer more protection for the gears against the constant snatch of the chain.

I don't believe it will change the bias of a helical type worth mentioning but may waste a little more power.

This may be indirectly of interest ... http://www.kushsprockets.com/

[NeilR]

Interesting idea re snatch. Re sprocket, thanks I have seen them before. Unfortunately all 520 chain size and we use 530.

[Grumbles]

cheapracer, on Jul 22 2011, 17:54, said:

This may be indirectly of interest ... http://www.kushsprockets.com/

Sorry to take this OT but that sprocket design is interesting. I've been thinking of incorporating something similar into a cam drive gear to help isolate torsional vibrations. There isn't room for a belt drive but a gear with a cushioned hub similar to those sprockets might be just the thing.

[bigleagueslider]

NeilR, on Jul 22 2011, 04:38, said:

I'm curious about gear lubrication in a Torsen T2 diff, which is at the end of the day a friction device.
Now Quaife and others sell their T2 Torsen diffs and recommend a specific oil lubrication...yet in the quaife's chain drive diff (which is a Fiesta diff in a can) they use HP grease. Would the change in lubrication feasibly alter the bias ratio? Any downsides to using grease?

NeilR,

The basic Torsen diff is based on cross-axis helical gears. These helical gear contacts have high localized pressures and boundary lubrication conditions. Using an oil splash for lubrication, as opposed to a grease, would likely give better life. The oil splash would give better cooling and would help flush any debris away from the gear mesh. Due to the high local pressures and boundary type contacts, an EP additive is definitely required.

The biasing function of the Torsen diff mechanism should not be affected by changing lubricant, at least in theory, as long as all of the sliding interfaces are lubricated the same. This would be possible with oil lubrication, but not as likely with grease. Getting grease to stay in intimate contact with gear meshes and rotating parts is not easy.

I'd stick with oil.

slider

[cheapracer]

bigleagueslider, on Jul 24 2011, 12:20, said:

Getting grease to stay in intimate contact with gear meshes and rotating parts is not easy.

I'd stick with oil.

It is when the whole component is emersed in it.

Then why does the manufacturer themselves who have been around for an awful long time and at the top of the tree supply it with grease but their same diff for all other applications with oil.

http://www.youtube.c...feature=related

[kikiturbo2]

I will go out on a limb an say that they did it to make their life easier and have a simpler design of the diff housing, which in this case rotates with the diff. If they used oil, no matter what kind of lip seal they used on the shafts, they would have leaks because the oil would expand a bit when hot and make some overpressure in the housing.. which you can easily deal with if your housing is stationary..

I am in the "make your own diff for your homebuilt" camp. and after some time finally decided to go for a stationary housing and oil in my torsen..

[NeilR]

I have made my own housing out of composite (CF/FG and Epoxy) for a Honda T2, but the seals are the challenge, particularly where the driveshafts go. Grease would make it all a lot easier.

[bigleagueslider]

kikiturbo2, on Jul 24 2011, 10:04, said:

I will go out on a limb an say that they did it to make their life easier and have a simpler design of the diff housing, which in this case rotates with the diff. If they used oil, no matter what kind of lip seal they used on the shafts, they would have leaks because the oil would expand a bit when hot and make some overpressure in the housing.. which you can easily deal with if your housing is stationary..

I am in the "make your own diff for your homebuilt" camp. and after some time finally decided to go for a stationary housing and oil in my torsen..

I'm assuming this is the type of differential that is being considered. If so, it uses grease because it is designed to operate with a chain drive. And incorporating the diff into another housing to contain the oil would not be cost effective for this particular product. But that does not mean that grease is a better choice than oil for lubrication of this differential mechanism. It just means that using grease is cheaper, and will give acceptable life. At least as long as the diff is greased every couple hundred miles or so. One can assume that getting the grease to stay in place is an issue with this diff design, due to the fact that it has 6 separate grease fittings.

[GrpB]

Yes, in a Torsen changing the lubricant characteristics can alter the bias ratio, for example using a GL5 lubricant instead of ATF (as some manual transaxles require) can change the bias ratio. Most anything that affects internal friction can alter the bias ratio somewhat, using plain steel thrust washers instead of coated washers, etc. Torsen can give an estimate of the approximate change in TBR if you contact them directly.

[NeilR]

good idea, I will do that. I have come to the conclusion that grease is too convenient to ignore. Principally because the Honda T2 we will be using has an acme thread cut into the driveshaft tubes to help control oil. However the application we have the diff in has the diff reversed from it's normal direction of rotation...so the acme thread would not be helpful! So grease it is.

[cheapracer]

NeilR, on Jul 28 2011, 15:08, said:

good idea, I will do that. I have come to the conclusion that grease is too convenient to ignore. Principally because the Honda T2 we will be using has an acme thread cut into the driveshaft tubes to help control oil. However the application we have the diff in has the diff reversed from it's normal direction of rotation...so the acme thread would not be helpful! So grease it is.

And then there's different greases but just a note that liquid grease is still available at any Indian Bullet dealership as they use it for their gearboxes still. I used to throw in half a handful of copper grease with it.

[NeilR]

cheapracer, on Jul 28 2011, 08:35, said:

And then there's different greases but just a note that liquid grease is still available at any Indian Bullet dealership as they use it for their gearboxes still. I used to throw in half a handful of copper grease with it.

yes there are. Quaife just us Castrol HP.

[24gerrard]

cheapracer, on Jul 28 2011, 08:35, said:

And then there's different greases but just a note that liquid grease is still available at any Indian Bullet dealership as they use it for their gearboxes still. I used to throw in half a handful of copper grease with it.

I thought grease was basical oil with a thickening agent.
There are lots of ways to keep oil in an assembly other than just oil seals, try thrower rings or shaft scrolls.

http://en.wikipedia....ase_(lubricant)

The solid additives usualy added to grease work for a short time and then the base oil takes over.
IMO this is not an ideal lubricating method.
Temperature increase is difficult to remove and there is the added problem of blocking small galleries etc.

[cheapracer]

24gerrard, on Jul 28 2011, 20:05, said:

I thought grease was basical oil with a thickening agent.

I worked around developing machinery for golf courses there at one stage for about 3 years and nothing I've ever come across suffers worse than the front rollers of fairway barrel mower heads and general usage pins/bronze bushes in the savage environment of a golf course - greases are not greases and molybdenum sulphide EP grease would be top of the list NeilR.

Castrol website ...

About Castrol Moly Grease

Castrol Moly Grease is a multipurpose grease fortified with molybdenum

It is excellent for swivel and shackle lubrication. It also shows excellent performance in the lubrication of heavily loaded slow/medium speed bearings of all types and is particularly useful in preventing bearing damage caused by excessive vibration or shock loading. When exposed to extreme operating conditions, Castrol Moly Grease helps prevent the depletion of normal grease lubrication by a residual coating of the metal surface with molybdenum disulphide to give 'dry' or 'solid' lubrication. Castrol Moly Grease also has an application in sliding motions where the prevention of scuffing is desirable and may be used in dry or moist conditions. It is not recommended for use in small, high speed ball and roller bearings.

Golf courses seem such serene places on the surface too, lets not even mention the pesticides and herbicides they are doused with .....

[24gerrard]

cheapracer, on Jul 28 2011, 16:41, said:

I worked around developing machinery for golf courses there at one stage for about 3 years and nothing I've ever come across suffers worse than the front rollers of fairway barrel mower heads and general usage pins/bronze bushes in the savage environment of a golf course - greases are not greases and molybdenum sulphide EP grease would be top of the list NeilR.

Castrol website ...

About Castrol Moly Grease

Castrol Moly Grease is a multipurpose grease fortified with molybdenum

It is excellent for swivel and shackle lubrication. It also shows excellent performance in the lubrication of heavily loaded slow/medium speed bearings of all types and is particularly useful in preventing bearing damage caused by excessive vibration or shock loading. When exposed to extreme operating conditions, Castrol Moly Grease helps prevent the depletion of normal grease lubrication by a residual coating of the metal surface with molybdenum disulphide to give 'dry' or 'solid' lubrication. Castrol Moly Grease also has an application in sliding motions where the prevention of scuffing is desirable and may be used in dry or moist conditions. It is not recommended for use in small, high speed ball and roller bearings.

Golf courses seem such serene places on the surface too, lets not even mention the pesticides and herbicides they are doused with .....

I often used 'moly grease' in gear systems under development.
After use for a while it tended to show up areas in need of improved oil lube and helped in the design of later production items.
I am not certain but I do not think I would use grease in preference to oil feed.
Dragsters use it but only for limited time periods.

[NeilR]

Well if you can suggest a reliable sealing method I'll consider oil.
Until then I may stick with grease.
First diff cover below - vacuum bagging was not well done, but it worked. Grease nipples feed directly onto helical gears. Unfortunately the finish is not as I would like, but I am rushed atm and will do a 'cleaner' one when it is proven to work!

[24gerrard]

Great job Niel, brings back memories of the old days.
Although the casing parts we made were mostly steel or alloy.

With a light car the loading on the components should be fairly low so it should last well.
So long as its greased often.
I hope it seals well enough.

It might be of interest, in the electric performance cars, two electric motors are used with belt drive to each drive shaft.
Diff action is undertaken with the control unit electricaly.

[NeilR]

Thank you. It was a rushed job fitting in around other things, but I think it will work. Seals will be silastic ones. The top of the housing has .5mm spacing from the steel of the diff and the bottom will have a bead of 5-8mm. The seals have no structural load and the cover is a form fit over the diff itself. It actually has to be tapped onto the diff to fit.

Edited by NeilR, 29 July 2011 - 11:29.