Ma Gearbox- Quaife Gearkit

[welshpug 1,622]

much much more than a DIY BE4 conversion, unfortunately for Nick he's limited to the original Casing, possibly Synchros too though I haven't studied the CC regs for his class.

[TT205 42]

much much more than a DIY BE4 conversion, unfortunately for Nick he's limited to the original Casing, possibly Synchros too though I haven't studied the CC regs for his class.

 

 

Has to be original casing, internals are 'free'

[205Rallee 59]

How did you get on with this?

 

 

Cheers

 

Nick

 

 

Well 2nd and 3rd synchros were dead by May 2009. So I bought a a load of new synchro rings, a new 1st, 2nd and 3rd gear from Quaife ("now with new coated gears"?) even though there was no visible wear on the gears and a new 1st/2nd gear synchro hub off e bay (couldn't stomach the Peugeot Stealers price).

 

Bunged it all back together with 2 litres of Total and it was transformed, it'll go from 2nd to 1st at much higher speeds than before with no complaints.

 

Not sure if the improvement is due to the new synchro hub or the gears, but a massive improvement!

 

I'd love a dog box but don't fancy driving it on the roads to events etc

Edited March 4, 2010 by 205Rallee

[NeoN 0]

Because the tolerances between synchro cone and hub are designed with the oil grade in mind, these are very close tolerances and rely on viscous drag from the gearbox oil to synchronise speeds between gear and selector hub, and hence allow the synchromesh to work. If you use the wrong grade of oil, it will mean the synchro does not function as intended, giving a notchy change.

 

I think you mean clearances, not tolerances.

 

Synchro.s are not 'designed' with an oil in mind, the synchro.s will be bought from a company that has tested them in the oil(s) specified by the manufacturer.

Or maybe just the friction cones - many current manuals have friction materials bonded to the cones, rather than use grooved brass-type materials.

 

Synchro.s will have passed the shift 'feel' and durability criteria defined by the manufactrer.

Synchro.s are tested on rigs in the same way as (wet) clutches, as they are basically the same, before anything goes any where near a gearbox.

The viscosity can have an affect, but so can the oil's make-up, which differs between manufacturers.

Viscous drag is actually a hindrance to smooth operation - the synchro. uses the friction surfaces on the cones to equalise speed before the gear can be 'engaged' and the drag just gets in the way.

Synchro.s will usually last longer when used with oils with stronger film strengths (typically synthetics), depending on the friction modifiers used - lithium is often used as an EP (extreme pressure) additive to help the diff. live; the opposite of what you really want for the synchro.s.

Using a synthetic can make the shift feel 'harsh', in that a 'thinner' viscosity can be used to reduce drag and losses with the same or better film strength to enable durability.

Harsh can often be defined as a faster shift for the same effort; a faster shift means energy is dissipated over a shorter time, so shock loads are higher.