Hi John -
I think Patrick's point is you have to swap the entire gearset from
the A70 box into an A90 or BN1 box. The A70 gears themselves are not
individually interchangeable between the boxes, but are
interchangeable in complete sets into an A90 or BN1 box. The A70 used
slightly different ratios if I'm not mistaken (at least that's what my
A70/A90 shop manual says).
I think the best way to keep the gears long term is to fill the box
with a good quality motor oil (preferably new), seal and keep in a dry
place. If you take the gears out and keep them seperately, you run a
greater risk of corrosion on little bits here and there, esp. when you
move the stuff around. Just be careful that you have to store the box
on its side, preferable topside up, as there is no seal on the front
of the gearbox so storing it shaft up/bellhousing down is not a good
idea.
I usually like to clean the outside of the boxes until they are free
of oil and grime, then use a permanent marker and mark any important
details on the casing (e.g. inspected gears on 25/1/2010, no rust,
filled with oil and sealed).
Best regards,
Alan
'52 A90
'53 BN1
'59 Jag Mk IX
'64 BJ8
On Mon, Jan 25, 2010 at 4:15 PM, John Harper <ah@jharper.demon.co.uk> wrote:
> Pat
>
> Sorry but we cannot leave this uncorrected and mislead owners with wrong
> information. Many more parts are interchangeable than you indicate.
>
> In general terms the BN1 and A70 and A90 Atlantic gearboxes are all from the
> same family. The BN1 is the same basic unit and was developed from the
> A70/A90 by fitting and overdrive. This replaces the whole rear end but also
> the third motion shaft which is unique to the BN1 and in short supply. There
> was obviously changes to fit side change parts but these are just bolt on
> and in any case Keith asked about gears.
>
> There are two sets of first motion shaft, laygear and third gear that only
> mesh as a set and cannot be mixed. The later set was supposed to be stronger
> but this does not appear to be the case.
>
> There are other things to watch out for. The main ones are that early A70
> boxes had shorter first motion shafts. Also the A70 had only an 8" clutch
> whereas the A90 and BN1 have 9". To accommodate this a recessed clutch cross
> shaft is fitted.
>
> There are other minor things to look out for but the message is never scrap
> an A70 or A90 Atlantic box.
>
> Best regards
>>
>> Hang on to the A70 gearboxes. I am quite sure that the 1st/reverse idler
>> gears are interchangeable, but the rest isn't.
>>
>> However all the gears from the A70 box may be fitted in place of the AH
>> unit.
>>
>> Best wishes for Australia Day
>>
>> Patrick Quinn
>> Sydney, Australia
>>
>
> --
> John Harper
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
>
> Healeys@autox.team.net
> http://autox.team.net/mailman/listinfo/healeys
>
> You are subscribed as healey.nut@gmail.com
>
> http://www.team.net/archive
_______________________________________________
Support Team.Net http://www.team.net/donate.html
Healeys@autox.team.net
http://autox.team.net/mailman/listinfo/healeys
http://www.team.net/archive
|