Author Topic: Bis box in aircooled  (Read 2065 times)

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dajwid

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Bis box in aircooled
« on: August 30, 2018, 09:54:15 PM »
I know this has come up in the past, but can’t find it anywhere.
Fitting a Bis gearbox in an aircooled.
If I’m right it has higher gearing top end.
What do I need to change, to make it fit?
I’ve just bought a cheap Bis box that will be stripped .

Pete126

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Re: Bis box in aircooled
« Reply #1 on: August 30, 2018, 10:17:26 PM »
Just the bellhousing  ;)
Pete.      il cavallo piccolo

dajwid

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Re: Bis box in aircooled
« Reply #2 on: August 31, 2018, 07:16:09 AM »

Rusty's Uncle

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Re: Bis box in aircooled
« Reply #3 on: August 31, 2018, 07:58:04 AM »
I know this has come up in the past, but can’t find it anywhere.
Fitting a Bis gearbox in an aircooled.
If I’m right it has higher gearing top end.
What do I need to change, to make it fit?
I’ve just bought a cheap Bis box that will be stripped .

Unless you have a tuned air cooled engine it will struggle with the higher Bis diff ratio so you might want to use your existing crown wheel & pinion  :)

dajwid

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Re: Bis box in aircooled
« Reply #4 on: August 31, 2018, 08:32:56 AM »
Rusty, now it’s getting technical.
The engine will be pretty much standard.
Is there much benefit of the Bis gearbox over the aircooled?

Rusty's Uncle

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Re: Bis box in aircooled
« Reply #5 on: August 31, 2018, 08:46:00 AM »
Rusty, now it’s getting technical.
The engine will be pretty much standard.
Is there much benefit of the Bis gearbox over the aircooled?

The actual gearboxes are exactly the same and the parts are interchangeable. It is just the diff and bell housing that are different.

1973/126

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Re: Bis box in aircooled
« Reply #6 on: August 31, 2018, 01:49:30 PM »
 The bis gearbox is a great upgrade but it only works well with a souped up engine in my opinion. It depends what you want out of your car make it more of a cruiser or usable round country lanes ;D
1972 Fiat 500
1980 Fiat 126

dajwid

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Re: Bis box in aircooled
« Reply #7 on: August 31, 2018, 07:26:14 PM »
Mine will be for around town
Engine pretty much standard

Rusty's Uncle

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Re: Bis box in aircooled
« Reply #8 on: August 31, 2018, 07:37:52 PM »
So first question is what is the condition of the original gearbox?

1973/126

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Re: Bis box in aircooled
« Reply #9 on: September 01, 2018, 09:21:51 AM »
 If you mainly going to use it round town and not planning to upgrade the engine I would just stick with the standard box. I think it is more usable that way.
 You only really benefit from a bis gearbox on the motorway.
1972 Fiat 500
1980 Fiat 126