I Read an article on Straight cut Drop Gears, for DCCD boxes.

1. Do Dog Boxes really need a rebuild every 1000km. May be they refer to rally teams?

2. Approx how long would a dog box last?

a. For spirited driving, 100 km a week?
b. Track, slamon, hill climb and sprint type events, once every 2 weeks?
c. I have not seen the straight cut gears mentioned when dog boxes are advertised.

Gracias

 

I think you need to ask those questions of API, Zen or TEG, but I do know of one dog box from an Impreza hillclimb only car (no road use) that after about 15 events the box locked in 2 gears due to a design fault, and upon stripping it the dogs were perfect.

 

The dogs in the dog box can wear out very quickly if you don't know how to change gear with a Dog box, I remember one rally raid team test driver was trashing dogs in less than 350km, the regular driver did a whole weeks testing (about 5000km) with no problems at all....

Simon

 

One of our gentleman rally drivers [ 3 rallies per year ] in a Version 2 STi with Medina dog box was told that ruined dogs after 50 miles was not unusual and that he should not be surprised by that.

He had done 200 miles and was might pi**ed off to have to put new ones in at a cost of about £200 each.

He sold the car.

Dogs do wear very quickly, perhaps not that quickly, but expect that a years worth of 1/4 mile or Time attack should see them off in my opinion.


David APi

 

Hi David

To the OP I did have a Modena dog kit but the 2nd gear dog tooth failure was really down to a design fault / hardening & material issue. It correct that I only did 300km's before it started slipping out of 2nd gear caused be premautre dog tooth wear. The actual gear teeth were fine and no issue whatsoever.
I solved the problem by replacing the Modena 2nd gear & slip ring with a bespoke set from a local engineering company who manufacture dog kits themselves.
Modena rep said the chipped dog teeth was down to driver abuse, but the very same problem with the 2nd gear was happening to most other users of that particular kit - so driver abuse unlikely.

From experience a proper dog box is hard work for everyday driving, not much effort required to change gear but believe me its no fun on road sections and only comes into its own on a rally stage / sprint course.

Car was only sold as I had no time to go rallying this year and was pointless to leave it standing.
Had to buy a Version 5 RA though just to keep me in Impreza land!!.

Cheers
Rob

 

That's a bit pessimistic David.

The dog teeth on my dog box were just like new, after several thousand miles of road and track abuse.

Even when i split the 3rd/4th cluster clean in half, there was nothing wrong with the dogs!

Steven

 

Steven just caught up with this !! If you're not knackering dog rings regularly, then you are not trying hard enough.

l'll have to get Mark A to ask you to get a move on.

David

 

Is Mark actually doing anything at the moment?

 

Lol

So:

Smashing all the teeth off a PAR Straight cut 2nd gear
Smashing all the teeth off a PPG Straight cut 2nd gear
Smashing all the teeth off a Modena Dog Straight cut 2nd gear
Smashing a PPG dog 3rd 4th cluster clean in half

Isnt trying hard enough?

I did a good couple of thousand miles on the ppg dog box, and it was the longest lasting, even surviving a 1st gear selection from 8500rpm in 2nd (oops!). Not to mention 2 time attack events, a track day, and 30 ish drag runs, all pretty much clutchless up and down the box!

Guess being taught to drive at 5 in an old tractor, teaches you how to use a dog box properly.

 

Thats very unkind, Mark treasures that car and calling it 'an old tractor ' is a bit steep.

David

 

I guess Mark owns the quickest tractor in the country then

 

Steven yhm.