Amazon: Diff swap

[Gary Byrne]

Hi Guys. I've recently bought an Amazon estate to keep my 2 door company. I intend using both Amazons as my only cars which will mean the odd motorway blast, plus trips to Germany and back. My B20 engined Amazon will sit all day on motorways/autobahns at a relaxed 85mph and I want the same from my Estate. As the diff ratio on an estate is lower than on saloons can anyone confirm if the diff is a straight swap into the estate casing or else is swapping the saloon axle into the estate particularly involved. ps I enjoy getting my hands dirty! Thanks

[classicswede]

Your location is near Bristol603, have you seen his red 122s about?

As to the estate I'm sure the diff will not just swap over. There used to be a bracket kit available to weld onto the saloon axle for this but it is NLA. You can make your own to do the swap.

[Gary Byrne]

Thanks classicswede, it'd be a shame if that is the case. I wonder if any other members can confirm this? My estate currently has a twin carb B18 fitted with a standard 4 speed box attached and seems to sit quite happily on motorways at 70-75mph. I will be fitting a rebuilt B20 with a fully rebuilt overdrive box which will help, but I really want my Estate to match my 2 door in all departments. (This will also mean lowered springs, polybushed suspension, gas shocks etc)
There is a Red 4 door Amazon on Minilites that I see quite regularly in Alresford but, as yet, I've not been able to corner the driver! Also very local to me is a very clean green 123GT.
See attached pic of my 131.

[Burdekin]

Hi Gary,

It could I think depending on what axle you have fitted, but I haven't done it so could be wrong. What axle have you got in the estate and what year is the estate? If you have the spicer 30 diff you could be in luck, check out the info here: http://www.volvoamazonpictures.se/po...powertrain.php. worth noting the Spicer (Dana) 30 in the Amazons will be a 10 spline axle as opposed to the later disc brake version with a 27 spline which was fitted in P1800e and some othe model Volvos.

This is the guy who sells (or maybe use to sell) the bracket kit for converting other axles into an estate: http://www.tinustechniek.nl/

[davidw6092]

I have a spare estate axle casing if you wanted to get a higher ratio diff fitted and still keep yours on the car till its sorted Cheers dave

[swedishandgerman]

It's just a personal thing, but I think the best set up is over-drive PLUS 4.56:1 or 4.3:1 rear axle. As standard, Amazon estates had 4.56:1 axles with 4 speed whereas 4-speed saloons had 4.1:1 which means that estates scream their tits off on the motorway

I found that over-drive with 4.1:1 was too much and the thing bogged down too easily on the hilly roads down here in Devon. I would just put the overdrive underneath the estate and try it before going to the hard work of switching the axle

It is possible to put a saloon axle underneath an estate, but you will have to modify the mountings. Conversion kit is available from CVI Automotive: http://www.cvi-automotive.se/en/arti...conversion-kit

[Derek UK]

If you think that cruising at 85 in 4th in your 131 is "relaxed" (your definition) I think you'll be more than happy with a good B20 plus OD in the Estate.
Consider that the factory 122S and GT's all have 4.56 axles, as do all Estates. This does make them lively, with all 4 gears being lower when compared to the 4.1 axle as fitted to non OD cars. The GT will pull the OD gear a bit better due to having more power but a warm B20 will match that. Back in the 60's when the cars were new there weren't many opportunities to cruise fast for long periods like now. Now, it's not unusual to be able to average close to the legal limit (UK) for a couple of hours without clicking out of OD. Consumption will improve a bit but mostly due a steady speed. Main advantage is noise reduction. Point taken from Adam's comment about an OD with 4.1 in hilly Devon but it still comes into its own when cruising, even with a B20A. 4.30 axles are rare, having only been fitted to the very last B20 Amazons and not all of them have it.
Conclusion - Fit an OD to both cars, you'll be glad you did.

[Bristol603]

Hi Gary,

I have the red 122S on Minilites. I live in Bishops Sutton. I have seen your estate as I have been driving out of Alresford (and your very shinny 131) and wondered about knocking on your door for a chat. Did you have a dark blue Amazon a few years ago?

Best Wishes,

Nigel

PS - I have a two post lift at home if that is any use to you when you want to put in your OD.

[classicswede]

I am also interested to find out for sure if the diffs will swap over. I do have both types of axle spare about that could be pulled apart to find out. I had even considered getting some gear sets made with a little bit higher gearing as the 4.1 is still a little on the low geared side of things for me. When you can pull away in stop gear from a standstill with the 4.1 ratio loosing that would not be much of a loss with changing to higher gearing.

The roads have changed since the amazon was produced and cruising speeds are higher. With an engine that has been played with a little the acceleration lost to the higher gearing will be minimal but the more relaxed motorway driving and improved fuel consumption will more than make up for that little bit of loss.

On roads where it is legal to do so a late B20 amazon with 4.1 diff (no overdrive) will cruise at 100MPH+ but the revs are a little high at around 5000rpm as where a 240 GLT at the same speed is just over 3000RPM in 5th. That is more the gearing I would like.

[swedishandgerman]

[QUOTE=Derek UK;1551699] Point taken from Adam's comment about an OD with 4.1 in hilly Devon but it still comes into its own when cruising, even with a B20A. 4.30 axles are rare, having only been fitted to the very last B20 Amazons and not all of them have it.
/QUOTE]

I think my 4.3:1 axle was originally from an 1800ES. Well, that's what the seller told me.

When I got it - it was a real gem to have found having a tag on it from some engineering company having been rebuilt - it had no hubs or drive shafts. Both of these were salvaged from my old, unbearably noisy 4.1:1. I fitted new seals, bearings and we spend a good while shimming the shafts properly

Fitting over-drive is the single most notable upgrade on my Amazon and I would recommend it to anyone. Combining it with the an axle specified for over-drive is on my list of other worthwhile upgrades; it is massively more drivable.

Mine's a B20A, so lots of low and mid-range torque, but lacking in high end BHP of anything with a different cam. Therefore it bogs down more than something with more BHP. There's a long drag of a hill nearby on the A30. With the 4.1:1, I used to have to cancel the overdrive and it would still lose revs in 4th. Now I can leave the overdrive engaged and it barely loses.

I would imagine a single carb 1800, particularly a heavier estate, would lose revs quickly on hills if combined with a 4.1:1 axle. So I very much agree; Gary, I'd leave the 4.56:1 underneath it but add the overdrive