FOR YOU METAL People, Just brake my Gear box tooth AGAIN your thoughts please.
Turbo Mini Forums

This is the second time 3rd gear has snapped a tooth off the laygear, nothing wrong with 3rd gear to make this happen as it was replaced last time with new.

do you think I could help it from braking off by grinding a small radius on around where the teeth are machined, as there is a sharp edge there at the base of the tooth. They say it works on cranks so thought about this??

Cheers
Matt

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

Why not get the roots of the teeth shot peened ?

WWW.TURBO-MINI.COM

can you put up a pic of the gear to show what you mean matt?,my first impulse is that may work if you get it treated afterwards ,also ,have you looked at the cryo treatment idea ?
regards robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

good idea Phil, just needed it before the 10th as i have a show coming up.

still got to get a gear as yet knowing my luck MS will have sold out.

Of rob i'll look for pic, should have last years one, its EXactly the same.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

Here are the teeth in more detail,

I've have roughly arrowed where i thought a radius might work.

Edited by Miniwilliams on 6th Apr, 2007.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

hmm , i think that a radius there may help ,then peening and watever other tretments are in fashion , but i think that the only other options are a different gear design and the ensuing expence , the cryo gear treatment has been getting a lot of good press in the usa mags lately so look into that matt ,see if its worth a try moneywise ,trouble with a radius is that where on the one hand it might rweduce crack propogation , it also reduces the root foundatin area ..,you could always not use the n2o??(bite my tongue)lol

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

just looking at that tooth matt , there seems to be quite a large swept area, is it poss the two shafts are moving away from each other ,under the torque of the engine ,and so causing the teeth of the gear to bear closer to thier tips and so weakening them could you check the shafts for straightness ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Cheers Rob, yes a few things to look into thanks. Trouble is I've been going out in 600 -800 bhp cars of late and the mini with the gas and on full chat now feels very slow, so i can't no use it. But then again i was ok without it.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

The trouble with 3rd gear is that end of the main shaft has movement as its only supported by the first motion shaft. If you could eliminate that movement it might last longer. Maybe a better condition gearbox and transfer casing that the bearing areas are tighter.
Paul

I seriously doubt it!

the casing is ok, as hoggy always checks it, but that is a good insite on a possible why, cheers boy.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

time for a turbo 2 litre k series matt?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

lol Rob a different engine is long over due, but not got the energy for a different conversion, and then on the other hand any one can get big power from a non mini engine, just trying to be different.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

i know the feeling mattt ,this 5 port stuff is a challenge.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

yes mate, but it's not the top part of the design thats the problem lol!

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

how bout directly contacting the gear makers and seeing if they can come up with a better design ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

good idea, but how many people do you know that break teeth?? If it was a large number we might get some where.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

Dont put 200+ BHP through it

LOL, sorry couldnt resist.

Have you not considered a Swiftune Dog Box, they are suposed to be bomb proof, though i suspect you want synchro??

KAD may be a good option, but then it will hit your wallet.

It would be interesting to find out what the ultimate load is for each gear. if you consider first gear, the torque transmitted to the wheels is massive, but the load the gearbox sees is less, basicaly the car apears lighter to the gearbox in first than it does in fourth. The load on the gearbox with your given torque may be above the ultimate load of the gear and it has given way. Radiousing the bottom of the teeth will reduce the stress point. By doing this you are then removing material wich might actualy reduce ultimate streneth. Im no expert, I leave that to peple like Dave Coxon.

I supose it all depends of the tooth is showing signs of stress or its simply just sheared off. If its sheared then there is nothing you can do other than redesign the gears.

Just my my mind set, which is usualy messed up

Edited by Sprocket on 6th Apr, 2007.

Just out of interest, what gearset is it?

Following on from my other thread, not that im in any way near your kind of power output.

I've seen the future and tbh its Pie

well if you went to them and said oi , my names matt woods and ive got a mental near 300 bhp mini world renowned and all that stuff ,and then said your gear broke what can i do ,they might say hmmm nice challenge matt ,heres a step you could apply that wont cost the earth that we dont do cos not many people have that sort of umph in a likkle spud .!!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Try looking at the way you drive.
When you come out of a 30 limit and nail it, are you in 3rd?
When you are cruising and a Porsche etc comes bombing past, you decide to chase it and embarass it, do you change down to 3rd?
You could be giving it a lot of stick that it cant handle with your 3000hp.
paul

I seriously doubt it!

Mini Sprocket, yes a dog box, i did think about it, just the onces i've diven before haven't been nice for a road car. This what what put me off.

I'm using the mini spares clubman gear set, it been ok for many year and is easy ish to get hold of which is why i use it.

Well rob if you no of some contact details i will ring them

well Paul coming from a 30 limit into a 60 limit I have to use 2nd as the car's so slow to spin up, but yes on a faster track if i'm doing below 65- 70 ish i do have to drop down, other wise i'll be all day waiting for it to spin up lol.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

It is quite clear, you are far exceeding the torque capacity of the SC teeth - the faces aren't damaging, but the tooth is coming clean off, not even as a fatigue based failure.
You are simply applying too much bending load to the tooth - I've done this and seen it several times on STBF tests at work.

Shot peening will - in my mind - have minimal effect, but will be bettter than no peening. The cryo treatment as Robert described is what I'd be looking to - on the whole transmission whilst it's apart...
I've heard only good things about this process.

However - it can't change the fact that you are applying too much force onto a single tooth. The Swiftune dog-box is an expensive, but serious option, with it's wide teeth, and made by the masters of Quaife...

In short - you have to do something; or it'll happen again...

Maybe you should look into a boost controller to limit the boost - or only use the giggle gas in 4th?

Hi,
Laughing gas and teeth pulling, hmmm.
Looks as expensive as going to the dentist too!
Cheers,
Gavin :)

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My Mini build diary

I did that to my Tran-X 2nd gear once.

Quite surprised, given the lack of traction in 2nd though.

Some say lack of traction, then sudden grip can be very harsh on gears.

As for Cryo. Ive just had my new T56 gears cryo'd. It is supposed to be very good.

Another option, although I think its more wear related, than strength, is Mikronite treatment. Supposed to give good friction reducing properties which could free up some power.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Ok, anybody got any contacts for the cryo treatment? I use it on some componets at work and the cost is huge!!!

As TD says, just gone that one step beyond ..... st lest the rest of us know where the limit is

Good luck with finding a solution short of paying Quaife r Tran-X whatever they want for a one off special set.....

Every day is a school day ...........

How fast and how expensive ...... the same question...