15 replies to this topic

[ac427]

I saw some of the Swiftune competition gearsets are Superfinished.

 

I was wondering if this was a good idea on a road going Mini?

 

I thought it may fractionally help things run quieter, last longer, decrease friction losses and so on.

[nicklouse]

Not needed for a road car as you will wear them in in the first thousand miles. It just gives the gears a better finish sooner in a less used car.

[Spider]

I've not tried them or looked too deep in to them but the gains would be in academic numbers (ie, very small), it may make the box slightly quieter, but even then, you'd likely hardly notice it.

If you are looking for real world gains that will reduce the losses in the box and extend it's life, 'blueprint' the box.

[PoolGuy]

It's very common in Mini Miglias, they're seeing better gear life and a measurable reduction in drag on rolling road roll down tests. Is it worth spending £400 to have a road car box superfinished? Probably not. It's not just gearbox components either, wheel bearings, cv joints and some engine components can benefit from it.

[imack]

My MED camshaft and followers are superfinished. (I got the superfinish as a free upgrade as I'd spec'd standard finish but they were out of stock of the standard finish in the profile I wanted)
I don't know exactly what the superfinish process consists of but it is an unbelievably smooth to the touch.

[PoolGuy]

I don't know exactly what the superfinish process consists of but it is an unbelievably smooth to the touch.

It's basically a big vibrating bucket with media in it to take off microscopic edges, stress riser, machining marks etc (I may have oversimplified that) Take a look at https://www.vibrator...vibratory-bowl/

[Gaz66]

So the way I see it is super finishing is controlled wearing in?
But surely when the engine/gearbox is run the superfinished items that mate with other parts will need to bed in again so therefor pointless?
Am I missing something or got it totally wrong?

[PoolGuy]

So the way I see it is super finishing is controlled wearing in?
But surely when the engine/gearbox is run the superfinished items that mate with other parts will need to bed in again so therefor pointless?
Am I missing something or got it totally wrong?

 

This explains it well, https://www.vibrator...-polishing.html

[ac427]

I've not tried them or looked too deep in to them but the gains would be in academic numbers (ie, very small), it may make the box slightly quieter, but even then, you'd likely hardly notice it.

If you are looking for real world gains that will reduce the losses in the box and extend it's life, 'blueprint' the box.

 

Is Blueprinting bring the clearances all to manufacturer tolerances or is there more to it?

[Spider]

 

I've not tried them or looked too deep in to them but the gains would be in academic numbers (ie, very small), it may make the box slightly quieter, but even then, you'd likely hardly notice it.

If you are looking for real world gains that will reduce the losses in the box and extend it's life, 'blueprint' the box.

 

Is Blueprinting bring the clearances all to manufacturer tolerances or is there more to it?

 

 

In a few words, that's pretty much it.

It does usually mean some machining of the case and making some shims.

I've found it makes for a quieter gearbox, that lasts longer and is usually leak free.

 

An example here is I've found on all gearbox cases I've measured that the faces that the diff output flanges bolt up to, when checked to the diff centre line they are angled or if checked face to face, they are closer together at the bottom than the top. This leads to shorter diff bush life as well as those in the side covers. It amounts to a loss in the drive train, and sooner or later, oil leaks from having worn bushes.

Here, I've just set up a case in the Mill, clocked in to both bearing tunnels (so they are square) and taken an initial cut, I put some red marker on it and you can see in this case, the back is higher than the front (the cutter has put a line through one side and not touched the other);-

 

 

This particular case here ^ is a brand spanking new one that had never had gears fitted in to it.
 

Another area that I have commented on a few times is the Transfer (or Flywheel) Housing Alignment to the Case. I'm yet to find one that's right.

You can see evidence of it on the Idler Thrust Faces;-

 

and the other side;-

 

 

When lined up, this is how much they were out (sorry, not the best camera angle);-

 

 

These operations are just time on a Milling Machine, while I don't know what the charges are for Superfinished Gears, i would guess this machine work would compare and isn't just a superfinished part, that may have been out of spec to start with, but brings all the parts together in much better harmony. I'll also add that even if the Superfinished parts are on spec, there's little point fitting them in to a case that's out of spec.

 

Likewise, it does mean working through the gears and shafts too, getting together select components.

 

As well as the other benefits I've already mentioned, I've found than when assembled on the bench, just turning the shafts over by hand, you can right away feel that the parts are fitted correctly, the smoothness and lack of just about any sound from it is telling in itself, they feel like the proverbial sewing machine.

[ac427]

 

 

I've not tried them or looked too deep in to them but the gains would be in academic numbers (ie, very small), it may make the box slightly quieter, but even then, you'd likely hardly notice it.

If you are looking for real world gains that will reduce the losses in the box and extend it's life, 'blueprint' the box.

 

Is Blueprinting bring the clearances all to manufacturer tolerances or is there more to it?

 

 

In a few words, that's pretty much it.

It does usually mean some machining of the case and making some shims.

I've found it makes for a quieter gearbox, that lasts longer and is usually leak free.

 

An example here is I've found on all gearbox cases I've measured that the faces that the diff output flanges bolt up to, when checked to the diff centre line they are angled or if checked face to face, they are closer together at the bottom than the top. This leads to shorter diff bush life as well as those in the side covers. It amounts to a loss in the drive train, and sooner or later, oil leaks from having worn bushes.

Here, I've just set up a case in the Mill, clocked in to both bearing tunnels (so they are square) and taken an initial cut, I put some red marker on it and you can see in this case, the back is higher than the front (the cutter has put a line through one side and not touched the other);-

 

 

 

This particular case here ^ is a brand spanking new one that had never had gears fitted in to it.
 

Another area that I have commented on a few times is the Transfer (or Flywheel) Housing Alignment to the Case. I'm yet to find one that's right.

You can see evidence of it on the Idler Thrust Faces;-
 

 

and the other side;-

 

 

 

When lined up, this is how much they were out (sorry, not the best camera angle);-
 

 

 

These operations are just time on a Milling Machine, while I don't know what the charges are for Superfinished Gears, i would guess this machine work would compare and isn't just a superfinished part, that may have been out of spec to start with, but brings all the parts together in much better harmony. I'll also add that even if the Superfinished parts are on spec, there's little point fitting them in to a case that's out of spec.

 

Likewise, it does mean working through the gears and shafts too, getting together select components.

 

As well as the other benefits I've already mentioned, I've found than when assembled on the bench, just turning the shafts over by hand, you can right away feel that the parts are fitted correctly, the smoothness and lack of just about any sound from it is telling in itself, they feel like the proverbial sewing machine.

 

 

Thanks Spider.

 

I just have a find a machine shop that is knowledgeable with Mini gearboxes and engines. Would Swiftune and the like off such services?

[PoolGuy]

Where are you based?

[bluedragon]

Would super-polishing make a straight-cut gearbox quieter? Maybe not as quiet as a helical box but in the ballpark? I keep reading that "if built properly" a straight-cut box can be fairly quiet if not as silent as a helical. At least such that the exhaust isn't drowned out by the gearbox! 

 

 

Dave

[nicklouse]

Would super-polishing make a straight-cut gearbox quieter? Maybe not as quiet as a helical box but in the ballpark? I keep reading that "if built properly" a straight-cut box can be fairly quiet if not as silent as a helical. At least such that the exhaust isn't drowned out by the gearbox! 

 

 

Dave

Not one bit.

[gav]

We noticed up to 10 degrees less on engine oil temps after the super finished gears were fitted...