Diesel 5th

[eob 7]

Greetings!

 

I'm in the process of cleaning up my gearbox before it goes back on and I'm considering fitting a diesel 5th because:

 

1: I have a diesel gearbox sitting around gathering dust

2: Petrol prices

3: I do a good few motorway trips

 

So... How difficult is it to fit a diesel fifth to a 1.6 gearbox? Is there a tutorial out there anywhere?

[Goliath 94]

I personally think it would be a good idea, the easier option would ofcourse be to fit the deisel box but then 4th and 5th would be longer.

I havent swapped gears in a be3 before but i have on other cars and mainly bikes, im pretty sure any be3 gears can go in any other be3 box (likewise be1) with only the gti-6 box being different.

If you have ever had a gearbox apart and messed about with gears before then i think you wont find it hard.

 

Or you could cram a gti-6 box on

[eob 7]

Pretty cool tutorial here on how to do a complete gearbox rebuild:

http://www.rallyparts.co.uk/cwp_change/

 

Taking the first few steps in mind, it seems simple enough. I like the idea of having the very close ratios of the 1.6 box, then an extremely high fifth to cruise the motorways.

[Fox 3]

Keep us updated with this, I'd be interested in carrying it out too.

[pug_ham 244 3 Cars]

Swapping fifth gear isn't hard, you can even do it with the box still in the car working in the nearside wheel arch.

 

The drop from a standard 1.6 fourth to on with a diesel fifth will be quite a large drop so it might not work out any more economical due to having to rev it higher in fourth to get decent acceleration in fifth.

 

70mph in fifth will be just over 3k with 4k giving 90mph but on a 1.6 engine it'll struggle on any motorway hills.

 

I ran my old 1.6 engine with the 405 SRi gearbox breifly which has the same fifth gear ratio as you'll have after this swap (but a longer fourth) & found it no good so swapped back to a standard 1.6 box.

 

Graham.

[eob 7]

Sorry Graham, I should've been more specific. I'm fitting the gearbox to an Mi16. I'm hoping for 'brisk' acceleration in the first four gears, but decent fuel economy once it's in fifth.

[pug_ham 244 3 Cars]

I wasn't sure if you were fitting it to a 1.6 (having seen your recent topics about the Mi engine) but I replied as if you were just on case after reading your project diary.

 

This ratio fifth gear was fine on a decent 1.9 8v.

 

IIRC Wurzel fitted the diesel fifth gear to a 1.6 box on his old Mi which Alistair H now has so he might be able to give a better opinion of this mix.

 

Graham.

[eob 7]

Made the swap tonight from a diesel box. It's a very, very simple procedure but watching where that single ball bearing from the selector shaft goes when you pop the shift mechanism off, and the use of a decent airgun is essential. I would recommend being very careful prying the cogs off too, I damaged one of the teeth on mine but not severely.