Iain's 20XE Trackday Nova

[Southie]

I found the valvoline pretty good thrashing about but that was on my old bikecarbed 1.4 engine.

[Benn]

Been offered a gearbox with a Quaife 4.2 FD which I'm tempted by as my third gear synchro is knackered again.

Please say you bought this.

[Iain]

It's not a full straight cut box, just a standard F20 with Quaife 4.2 straight cut final drive. Been doing some number tweaking and with a F18WR fifth gear fitted I'd retain the same RPM for motorway cruising and get quicker 1-4 gearing.

[Benn]

Yep, my mate has a WR final in his Astra GTE. Just for motorway driving, at 70 its revving at 2.3k.... It's lovely. Wish i knew of it before fitting a F28.

[scott.parker]

Interesting, so an f18wr is wide ratio? is it an easily sourced part and easy to fit to an f20?

[Mazz]

iirc you just need the 5th gear out of it and bang that in an f20 and you've got the best of both.

[burgo]

Sam detailed the 5th swap in his diesel astra wip

[Iain]

Update Part #1

So I bought a new gearbox as I've knackered the third synchro in my current one too Its still fine for road use but graunches on track giving it the beans.

Got myself an F20 with known history including a full rebuild/inspection 2000 miles ago, complete with Quaife straight cut 4.2 final drive on standard F20 helical gearing.

First off, I was a bit concerned with the higher FD and the maximum speed, so I've notched the chassis so I can change 5th gear without dropping the gearbox:

No access to 5th cover bolts here:



Chop chop grind grind:



Weld weld, grind grind:



Paint paint, good as OE

[Iain]

Update Part #2

On with the box swap. Harvey brought me round some goodies and started unwrapping my pressies:



Nice and clean so saved me a cleaning job there:



Meanwhile I was whipping off the engine mounts to get the box off:



Slight mishap with removal, the input shaft stayed in the clutch when we dragged the F20 off, wtf happened here Not investigated the old box yet.



Brokened



Swish new box doesn't look anything special here



Or here, standard gearing inside:

[Iain]

Update Part #3

We swapped the selector turret, diff, diff bearing races etc over to to the new box so mine got stripped down:



This is where the differences are, my 4.2 final drive vs old 3.55 one:





Old pinion in old box:



New pinion in new box:



Harvey fitting up the crownwheel to the Quaife ATB:



Many other Vauxhalls run a spigot bearing to stop flex on the input shaft within the end of the crank, so I figured why not fix one on the XE, can't do any harm. Remove the clutch to reveal the crank:



INA bearing part number:



Fitted with a tickle of the hammer in: