What is the difference between an 8v and 16v final drive gear? And/or, how could I tell which one I have? Casing is a 4T, 100mm output cups, 4th and 5th gears are known FD/FM items and the box uses an 8v clutch disc. I'm mainly wondering if I could get the Kaaz diff (which I believe will fit any 020 box) and the 4.7 final drive into a 2Y box - as they are a little easier to come by.
4T comes with a 3.67 FD, but an FM/FD comes with a 3.89 FD So since you've got a mix/match, it's impossible to say without driving it. Revs at 70 mph, worked backwards through a spreadsheet with a known tyre diameter, and known 5th gear will give you the answer though. A 4.7 is horrendously high, and I'm not sure where you're thinking of using that! That's a rally FD ratio!
Oops, I meant 4.47, not 4.7! Originally the box was meant to have a new 2Y gear set in it but as a bit of testing went, there was a big drop between 3rd and 4th, which lead me to believe that quite possibly the 4T 4th and 5th gears had been retained. When 4th and 5th were changed for known FM/FD coded 4th and 5th cogs, this then made 4th feel very, very short. With the box in need of few new bearings, all I want to achieve over the winter is some good spacing between all the gears, hence the 2Y box and putting my 4.47 into it... ... but I dont know if that's possible with the bit's I've got?
Hi James, I have built boxes using 8v final drives and complete 16v internals apart from the 4th gear which needs to be an 8v item to fit the final drive shaft correctly. You also may need a few other little 8v parts on the 5th gear assembly to get the correct fitment. Can't remember exactly what they were now. As you already have the correct 8v 4th in your current box, you should be fine. When the 16v box is apart, you can line up (or count the teeth) both 4th gears from the 8v & 16v just to make sure they are the same. Also make sure you use a mk2 casing as I found the 1600 mk1 cases don't have enough clearance for the 100mm cv cups. Regards, Gurds
Alright G, Am I right in thinking if I was to buy a secondhand 2Y I could pretty much move over my diff, 4.47 final drive, input and output shafts and 4th and 5th gears from my current box and use them with the 1st, 2nd and 3rd from the 2Y? No major issues?
Yea James, that shoud be it. DaljSD and Nav16v both have 2Y 16v boxes with 8v final drives in them. Gurds
Cheers G, will have to keep my eye out for a good 2Y, I thought I was going to end up in a right mess but it sounds like it will be ok and straightforward. Chris - this will be for my Mk1 track car.
If your rebuilding the box, i've got an old knackered 2y, all the gears worked ok just whined like a straight cut (bearing?) Started stripping it but got bored. If you've not done your annual jaunt down this way yet you could grab it.
Sadly already been down that way for the year, otherwise that would have been ideal, so long as at least 1st, 2nd and 3rd gears are all good. Mine has that slight straight cut soundtrack too.
As for final drives, if your not intending to spend mega money then your only choice is 8v ones. Meaning of you do have a 16v 2y box you'll need to source an 8v 4th to fit the shaft.
