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What ratio should I go for

4.55:1
0
No votes
4.3:1
0
No votes
4.1:1
4
100%
3.9:1
0
No votes
3.77:1
0
No votes
 
Total votes: 4

Mike Allfrey
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Joined: Thu Apr 06, 2006 10:14 am
Your interest in the forum: It is a good vehicle for getting Jowett information to others.
Given Name: Michael
Location: Melbourne, AUSTRALIA.

Post by Mike Allfrey »

Dear Alastair,

Sorry,

Should have mentioned that i was nervous about the Nissan diff on account of fears that 3.90:1 would have been too big a step. I am certain I was correct in that assumption.

A Jupiter owner here has gone for 3.90:1, but he also went to smaller wheels, which for me is a definite non-event.

We hit 46.4 degrees C in Melbourne today, not at all pleasant, and Victoria is burning in several places.

Regards,

Mike Allfrey.
E0 SA 42R; Rover 75
Drummond Black
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Given Name: Drummond
Location: Kirkliston, SCOTLAND

JUPITER GEARING

Post by Drummond Black »

A tad warmer than when we were in Victoria. We have just put some Australian relatives on the plane to return to Melbourne. Leaving Scotland at around -5 C to the heat in Victoria will be a culture shock. They all loved the Jupiter so you might get a visit when it gets cooler. Keep the info and comments coming in Mike, between cold drinks, as your information is invaluable.

Cheers Drummond
garthwright
Posts: 23
Joined: Mon Oct 06, 2008 10:35 am

Post by garthwright »

Only just picked up on these interesting exchanges - too busy waiting for a reply re subject 4.11:1 ratio raised a while back!
Could I ask for any help/advice with the continuing disaster of my rear axle rebuild with a 4.1:1 CWP set from the JOAC batch - someone commented they are prone to whine - which after 3 rebuilds to try to cure the whine appears an understatement. I am prettyn sure now that I will have to give up on these unless anyone has found a specific cure/regrinding ??
As a ratio the 4.1:1 is great. But the noise has ruined the drive (severe whine on overrun in spite of pinion preload checks/remeshing etc. ect.).
Having over eagerly given my standard CWP to a Club Member in distress, I am left trying to find a solution - which seems to be either trying to find a standard rear axle to refit, or is there a source of good quiet 4.11:1 CWPs which I could have refitted to my otherwise 'new' axle !?
Alastair Gregg
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Location: Corrie, Isle of Arran.

4.55:1 / 4.11:1

Post by Alastair Gregg »

Hello Garth

The news I have is not great. I went to the TR specialists. They confirm the axle is not the same as the TR, or the MGB, or anything else they can find. The only option I have not confirmed as no go was the Morgan of the 50's-60's era.

The Pinion bearing size seems to be the issue. I have a spare Javelin 4.875 :1 knocking about to get you going if that will help, but not 4.1 or 4.55:1

Ed Nankivell was the gent who confirmed they are prone to whine. He got his to an acceptable level after the third attempt I believe.
Compliments of the Season,

Alastair Gregg
Drummond Black
Posts: 448
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Given Name: Drummond
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GAMBLE

Post by Drummond Black »

Alistair, Just to let you know that the LH O/D is in place and is testing as planned. As of now I have completed nearly 300 miles and the engine is settling in nicely with the Aus pistons. The car pulls well in overdrive and slips in and out on demand. My calculations are as predicted. At 70 in O/D top engine is pulling 3250 RPM. The drop in noise level is so noticeable. Just noticed that the rear axle has a leaking pinion seal, so next job is on the go. Have you decided your route yet ??

Drummond
Alastair Gregg
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Location: Corrie, Isle of Arran.

Route to go

Post by Alastair Gregg »

I have a little piggy (bank)!

It is marked overdrive unit, sadly only coppers in it yet but from little acorns mighty oaks grow. I think I will probably go down the generic O/D route as I am keen not to cut up any propshaft metal should I ever decide to return to standard (I can't see why I would , but you never know). I can also use std gearboxes without any industrial strength modifications too. The only butchering is the battery boxes as far as I can tell. At best it is a next winters job at worst the one after that.

Thanks for your help and advice,
Compliments of the Season,

Alastair Gregg
garthwright
Posts: 23
Joined: Mon Oct 06, 2008 10:35 am

Post by garthwright »

Alastair

Thanks for you info. I have now had a few other conversations around the problems with this batch of 4.1 gears - I certainly haven't yet come across any recent successful installation ? I will continue to contact those trying to see if inspection of the gears not yet fitted reveals anything.
It seems even finding a standard set will be increasingly difficult so somehow sourcing 4.1:1 or raising within the club the possibilty of making some good sets may be the only way to get motoring. Would sourcing from the same supplier as the TR sets be an option ?
Longer term for those not wishing to go the overdrive route and for future diff rebuilds generally this may be a subject to raise again with one of the clubs.
I have been offered the possibilty - at some considerable cost which I can't envisage yet - of machining a casing to take the 4HA axle parts for which the 4.1:1 sets are available. Does anyone know if this has actually been done, fitted and tried ? It does seem a bit of a risk in losing originality should a solution for the 3HA's be found.

regards

Garth
Drummond Black
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aXLE

Post by Drummond Black »

Garth, Mike Allfrey in Melbourne, and a few others in Australia, have indeed carried out this mod. I have driven Mike's car and it has good crusing revs. His is about 4.11 : 1. See earlier post on this subject.

Worth thinking about. Drummond
Alastair Gregg
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Location: Corrie, Isle of Arran.

4HA et al

Post by Alastair Gregg »

Hello Garth,

The TR company buy them from an importer who brings in Healey TR and MGB CWP sets. They are manufactured in Germany, but the importer is based in Mansfield (Notts). I fear there would be a major cost implication in having a batch made.

I wish I could be more help.

But will happily start the ball rolling and make contact with the importer if it will help.
Compliments of the Season,

Alastair Gregg
garthwright
Posts: 23
Joined: Mon Oct 06, 2008 10:35 am

Post by garthwright »

Hi Alastair

Thanks for further info. I would be interested to know what cost as I don't have many options left !
Am trying to find out what happened to all the other CWPs in this batch - perhaps there would be others interested?
I drained the rear axle oil today after about 250 miles on these whining 4.11 gears and it is full of fine metal particles in suspension, so reckon there is something wrong with them after all the resetting - probably ought to now lay the car up until I find a solution.
I am touting around to see if anyone has an old standard Jupiter axle, but otherwise will need another CWP set or start diverting what's left of my pension fund into a 4HA conversion !
I have a spare Javelin CWP but don't want to go this low on ratio after tasting the 4.11.
Drummond confirms some of these 4HA conversions done in Australia - haven't heard of any in UK yet so not sure who could do it or how much of a guinea pig I would be going this route over here.

regards

Garth
Alastair Gregg
websitedesign
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Joined: Sun Aug 27, 2006 10:43 pm
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E2 PD 22113 MVU 377
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Location: Corrie, Isle of Arran.

New CWP set

Post by Alastair Gregg »

Hello Garth,

I will make enquiries from the TR place who I hope will put me directly in touch with the importer. I think you need the might of one of the clubs behind you as the NRE (Set up charge) is likely to be eye watering and the price will not be low per CWP set either. This will take a couple of weeks at best so please be patient, but I will do it.
Compliments of the Season,

Alastair Gregg
Mike Allfrey
Posts: 491
Joined: Thu Apr 06, 2006 10:14 am
Your interest in the forum: It is a good vehicle for getting Jowett information to others.
Given Name: Michael
Location: Melbourne, AUSTRALIA.

Post by Mike Allfrey »

Dear Garth,

I was very concerned to read about bits of metal in the differential oil. Has any analysis been carried out on the oil sample?

Caterpillar dealers can do an oil sample analysis that is not at all biased as some can be from the oil companies.

There are some points to consider:

1. Is the correct type of oil being used?

2. Are you sure that the 'metal pieces' are from the crown wheel and pinion?

3. Has anyone carrird out a mechanic's blue test on the actual mesh?
This is time consuming, but can tell/illustrate a great amount.

4. Has the 'pinion height' been measured? This is not easy, but if the pinion height, in relation to the axle centre-line is not correct, metal pieces in oil can result and it may be time to walk away from it.

5. Is the crown wheel carrier (differential housing) running absolutely true at the crown wheel face?

6. Has anyone listened to the noise from the roadside while the car is driven past?

7. Is the half shaft end float correct? Pre-load here can cause accelerated wear at the spacer between the half shafts. More metal pieces!

8. A stupid question, but, are both rear wheels of the same rolling radius?

A Caterpillar oil sample analysis should be able to identify the metal that is in the oil - bearing metal, gear metal etc.

In my experiencem playing around with new gear sets in old housings can be fraught with problems. The pinion height concern being the one that can not be adjusted out of the whole assembly -- and yet it is the most important dimension in the entire assembly!

I hope this helps your situation,

Good luck,

Mike Allfrey.
E0 SA 42R; Rover 75
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