Tolerances of rebuilt box
Turbo Mini Forums

I have just rebuilt a 4 synchro remote box with new bearings, straight cut gears and mainshaft etc. The mainshaft is fitted to the casing and not yet fully torqued up as I am still checking everything. 1st and 2nd gear spin freely on the mainshaft with aprox 5-10 thou side to side play. My concern is 3rd and 4th gears. The gears have no play side to side at all. The baulk rings are up close to both of these gears which is preventing them spinning as freely as the other two gears.
Is this normal and as it should be? Is it just a case of the baulk rings for 3/4 gear needing to bed in?

dont run it like that, i made the mistake last year and had to buy a new 4th gear

i ended up playing around with the old baulk rings and ran something like 3 new rings and 1 old ring

i think you can grind them down with something like a grinding paste, but i didnt fancy that

turbohoggy is your man to ask here

Your ring is over-hanging the front of the gear as Nic points out. I never used to have this the first two times i built a box, then it occasionally started happening, in my case it was bogus rings... It could also be down to the gears having a synchro cone gauge diameter either on the limitof upper tolerance, or indeed over tolerance.

As pointed out, some selective assembly or inspection and modification of the parts is required. Just getting the new baulk rings on a surface grinder and taking 10-thou off the front face (the face where the three external blocking ramps 'point to') will likelyallieviate most of the problems - or just take the easy option and re-use a synchro ring. Next time you have the box apart you'll probably be able to run a brand-new ring as the moly coating on the gear will be bought closer to gauge-spec.

Edited by turbodave16v on 6th Jan, 2007.

I have now torqued up the 1st motion shaft nut and the pinion nut and lubricated the hubs a little. The box has now loosened up nicely. 3rd/ 4th gears now have a little sideplay when the box is in neutral. I can see that the baulk rings are just clear of the 3rd/ 4th gear hubs with the box in neutral. Will this now be acceptable to run. I don't want to knacker anything.
Quick question - When the gearbox is spinning fast in neutral what prevents the baulk rings touching the hubs and wearing themselves out?

ist lesson lernt there, never panick until you have done up both nuts as this the pulls the main and first motion shaft apart given you the clearance, 1st , 2nd and 3rd gear should have much side ways movement but may have a little if you try and twist it, but be carefull to much will wear out the gear teeth on the gear and the correwsponding laygear teeth.

always looking for them bigger bunches of bannanas

Thanks for the info. This type of stuff aint covered in the Haynes manual. It's my first gearbox build, I don't have another to compare it with so I'm erring on the side of caution.

I've had the same happen as well. Use 2nd had rings as adviced.