JKD involute gearbox
Turbo Mini Forums

Whilst I was talking with the boss last week, he says he has had some dog teeth machined off his gearbox (some single seater jobby) The idea being behind it is to remove every other dog tooth allowing easier engagment. Saying he can flat shift up and down almost sequential gearbox style.
The box he runs uses only 8 dogs machied down to 4.
The JKD box uses alot more dog teeth, Would this be any benifit to carry out a modification such as this? Obviously I dont want to weaken the dogs too much as getting spares is neigh-impossible

Thanks

Dave.

David.

in thorey yes on a face dog box as the chances of misisng the engagment would lessen, but the downside is the dogs are verty small on the old jkb boxes , just bigger cersions of a standard box and would be prone to failure of premeture wera as a result of there being less,

you just need to learn to use these boxes better as there are no spares available



carl

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Thats what I was worried about, If i had known that JKD would stuff it when i bought the box, I'd have gone with the Swifty box with the more conventional chunky dogs and spares available, as I've now heard how easy they are to use.

I've used the car a fair amount now, (at least when the car was on the road) and still find trouble shifting clutchless at times, its very hit or miss and its usualy when I really dont want to miss gear, such as at Avon. So im just thinking of ways to make use a little easier without biting the bullet and going over to the Swift tune box

David.

Is this right. I don't see how reducing the dog teeth will reduce the chances of missing gears. My thinking is that the angle between dog and slot being lined up and being a maximum away from being lined up remains the same no matter what you do to the teeth. The only way to improve the chances is to have lots of engagement for the dogs, the maths doesn't work when you reduce the number of dogs, only when you increase the number of slots.

So you really have a better chance of engagement with more engagement slots, the number of teeth is irrelevant. but for strength it makes sense for the number of dogs to equal the number of slots .

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