I am getting near to finishing my 1963 1098cc traveller and I am thinking about changing the diff for a faster top end and better mpg, can anyone tell me the best one to get for it please?
heres the rust I chopped out (well some of it), it had a full 12 months mot when I got it! lol. body/chassis is all done and just waiting for the wood to arrive, not bad going for 9 weeks work .
Hahahaha - I like that picture of the rust - well done! If it's a standard 1098 engine I suggest going to a 3.9 final drive - if it's modified then 3.7. Have to say - it really doesn't make a significant difference to the mpg - it does drop the revs slightly, so perhaps a bit less frenetic at speed. And changing the ratio doesn't raise the top speed - you need more power to do that!
That's an impressive photo! I'm in the process of restoring a Traveller and I'm keeping all my rusty panels in a large plastic box, it's already filled to the top and I'm only a quarter of the way through. Not sure what the answer is to your diff question but I would like to know the answer too.
Hi
I've got a whine from the diff on my 1956 Series II. Should I change the diff or just live with it? If I should change it what's the best ratio to have for an 803cc engine?
Thanks
Robert
Robert wrote:Hi
I've got a whine from the diff on my 1956 Series II. Should I change the diff or just live with it? If I should change it what's the best ratio to have for an 803cc engine?
Thanks
Robert
A whine isn't too bad, if you can put up with it. Check the oil level and top up if necessary, that could help to muffle some noise. If it starts clunking or grumbling you want to think about it more.
A standard 803 would have had a 4.55:1 diff if i recall correctly. You'd be hard pushed to get a reconditioned one, but always worth asking around to see. You could look for a second hand one, but it might be worse than what you've got!
The standard diff on an 803 is 5.375:1, which is unbelievably low. There's good reason though, as the 803 really wouldn't be much good at coping with a longer ratio final drive. If you are going to change it, I definitely wouldn't go any higher than the 4.55:1 of the standard 948, the 803 just doesn't have the torque to cope. I wouldn't even fit a 4.55:1 if you live near any hills... The diffs in the 803 cars are quite easy to sell now I think, as people using cars for hill climbs like them, so you could find it's worth a bit more than a more common diff out of a later car.
I've got a 3.7 diff on my pickup coupled to a 1098cc engine but with a mini cooper head and a Marina carb and inlet manifold setup. The higher ratio works well but the weak link is the clutch which takes more of a beating than with a standard 4.22 setup. Also, I am usually the only one in it so it rarely carries and loading beyond its tare weight.
If you're using a standard 1098cc engine, then I wouldn't go higher than a 3.9 but you then have to weigh up the cost involved. 3.7 and 3.9 diffs are now changing hands at a couple of hundred pounds so unless you can find one cheap, you may think the standard 4.22 setup is the best one to stick with until you stumble across a higher ratio diff.
The best way to go is of course a 5 speed gearbox but then you are talking megabucks. Moss do one for £1,700 new but again if you can find an old Ital and scrounge the box (and engine ) out of that, that would be a better bet.
Thanks for the useful info and help, I go to all the autojumbles nearby where I live so I might just find a 3.9 or a 3.7, but how do I know what they are, is it stamped on the casing or is there part numbers I need to know?
All I want to do really is be able to maintain a steady 65mph on the M/way, 70 would be nice.
I've recently fitted a 3.9 diff to my car, as yet I haven't even got onto a motorway, just driven a large circuit near my hose as a maiden run to check for leaks, noises etc.
What I can report from this limited use is that it makes first gear actually usable, rather than something to stay in for a micro second, or avoid if at all possible.
After the Kent Hop I'll report on motorway performance.
"Once you break something you will see how it was put together"
To get speed on the M/way - you need POWER. If the engine is down on power, changing the final drive won't help. With my warmed up 1098 and 3.7 ratio - my Trav will do 70 in 3rd gear - and no problem holding 70(!) in 4th.
In complete contrast, i'm currently running a very mild 1300 (still with standard Minor carb and exhaust) in the van with a 4.55 diff. (Meant to fit a 4.2 years ago when the old one broke but must have picked up a 4.5 by mistake)
And its an absolute hoot to drive round here on rural hilly A and B roads. Rarely need to change down from 4th and very effective accleration for overtaking!
The first motorway journey I did a few weeks back was a little disapointing though. Max speed governed by noise and a degree of mechanical sympathy. 70mph is getting on for 5000rpm so I think we'll be having a diff change before long even if it could out drag a Mercedes Sprinter on a short length of dual carraigeway the other day...
cheers
Iain
Fairmile Restorations.
'49 MM, '53 convertible, '55 van, and a '64 van.
Marina p.u., '56 Morris Isis Traveller, a '59 Morris JB van, a'66 J4 van, a '54 Land Rover, Land Rover 130, Renault 5, '36Railton, '35 Hudson, a Mk1 Transit and a Sherpa Camper...
A car can be restored at any time, but is only original once!
I was surprised meself! We both set off side by side, me starting in 2nd gear so only two gear changes. He was startign to creep ahead by the time we got to the next roundabout and had to slow down, so it was only up to 60ish. Any further distance and he would have been gone as I was running out of revs at that stage and he was probably still in third with a full load on board!
Still its one less white van man who assumes all old cars are slow!
May keep the low ratio diff for a while at least as today I used it for towing a Hudson Terraplane so it was a bit kinder on the clutch...
cheers
Iain
Fairmile Restorations.
'49 MM, '53 convertible, '55 van, and a '64 van.
Marina p.u., '56 Morris Isis Traveller, a '59 Morris JB van, a'66 J4 van, a '54 Land Rover, Land Rover 130, Renault 5, '36Railton, '35 Hudson, a Mk1 Transit and a Sherpa Camper...
A car can be restored at any time, but is only original once!
the storys are entertaining but I still dont know how to identify a 3.9 or 3.7 diff, can anyone tell me please?
If you want to be quick of the line and have a good top end too why not come up with a way to put a Daf 33 or 44 variomatic drive in your moggy, I have a Daf 33 and keep thinking about putting a sporty engine into it, it would be a real flying machine , but its too nice to mod (2 owners, never welded, 24k from new).
The variomatic drive was banned in formula racing in the 60s as no one could keep up with it!
The De Rooy brothers fitted Ford BDA engines and 4 wheel drive to their Daf Rallycross cars - retaining a version of the belt drive transmission - they were pretty much unbeatable in the mud and snow at Cadwell ! This video in the dry (no idea where - later shots are at Lydden) - and they still seem competitive. The constant speed HOWL from the engines was absolutely amazing - as the transmission varied the speed without any gear changing. http://www.streetfire.net/video/rallycr ... _89019.htm
the storys are entertaining but I still dont know how to identify a 3.9 or 3.7 diff, can anyone tell me please?
If you want to be quick of the line and have a good top end too why not come up with a way to put a Daf 33 or 44 variomatic drive in your moggy, I have a Daf 33 and keep thinking about putting a sporty engine into it, it would be a real flying machine , but its too nice to mod (2 owners, never welded, 24k from new).
The variomatic drive was banned in formula racing in the 60s as no one could keep up with it!
thanks in advance and best regards,
Eric.
Never experienced a Variomatic. Sounds fun!
The numbers of the teeth are stamped both on the diff casing (on a flat area near the bit where the brake pipe bolts on) and on the edge of the crown wheel. 9/38 for eg is a 9 tooth pinion and a 38 tooth crownwheel. Divide 38 by 9 and you get 4.22 the standard late car ratio. I think (without checking) that the3.9 is 10/39 and the 3.7 10/37
cheers
Iain
Fairmile Restorations.
'49 MM, '53 convertible, '55 van, and a '64 van.
Marina p.u., '56 Morris Isis Traveller, a '59 Morris JB van, a'66 J4 van, a '54 Land Rover, Land Rover 130, Renault 5, '36Railton, '35 Hudson, a Mk1 Transit and a Sherpa Camper...
A car can be restored at any time, but is only original once!
(well some of it), it had a full 12 months mot when I got it! 
lol. body/chassis is all done and just waiting for the wood to arrive, not bad going for 9 weeks work 
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but I still dont know how to identify a 3.9 or 3.7 diff, can anyone tell me please? 
