A friend is building a grass tracker at the moment powered by a Vauxhall XE engine but connected to a narrowed Sierra back axle.
Given its use, a live axle is required and the easiest way to achieve this is to weld the diff.
We have taken the diff out and pulled it apart, cleaned it up and its ready to be locked up. Does anyone have experience of doing this? It doesn't look to difficult but every big project seems to start with those words. Any advice would be very helpful!
Yes, but a heck of a long time ago when I raced F2 stox! - it is easy but if I described it and you welded the wrong gears!..... if you are unsure why don't you ask a local driver from the club you'll be racing with - I've always found the Stox and Grass Track mob very friendly and helpful!
I would dismantle the diff, drill and ream 3 holes at equidistant points in the gears, so they align, then turn a coupling pin, tapered drill and tap a thread, insert and then screw in a length of threaded rod until you achive the correct pressure.
Originally posted by ProfJC: I would dismantle the diff, drill and ream 3 holes at equidistant points in the gears, so they align, then turn a coupling pin, tapered drill and tap a thread, insert and then screw in a length of threaded rod until you achive the correct pressure.
You don't need to get that complicated, Prof - it is only a question of spot welding some of the gear teeth - I did it and then raced using that diff for a season, so I know that you don't have to do all the things you have suggested!
As I said just have a word with other members of the grasstrack club you are racing at, someone will be able to tell you!
Thanks for the advice B308. My mate Tony has grasstracked for a few seasons but was racing a ready built car. The new car (MK3 Escort with RWD conversion) is, apart from the shell, being built at home but he has had lots of help from his club...my only input was sourcing the back axle and a promise to help sort it out.
We were working on the basis that its a case of welding the pinion gears to everything they touch to lock the whole back end up.
Sorry Prof but I'm a bit lost on your method. Which gears would be drilled and tapped? Would you be bolting them to themselves or to the diff csing and if so, is there not a risk of oil leaks / splitting the casing?
Originally posted by MonkeyAlan: Thanks for the advice B308. We were working on the basis that its a case of welding the pinion gears to everything they touch to lock the whole back end up.
think it might well be - its a few years ago now! We used the Mk1/2 Escort or Capri rear axle. We always used to carry a spare diff and half shafts(!!) - I thought someone might have one you could look at!
Also the tracks were different sizes so different diffs were used - if memory serves me right we used the likes of a 4:1 or 4:4 (rare beast) on the tight tracks such as Taunton or Hartlepool and the 3:7 or 3:9 on the larger tracks such as Newtongrange.
One of those super jobs changing a diff without the halfshaft puller - lots of banging with a large hammer and hoping it wasn't stuck! Even better when you had broken a wheel off and it had snapped the bolt holes on the half shaft - and you had to chisel out the bearing to get the half shafy out! Oh joy!
