final drives

[DTD 416L]

can some one please tell me the final drives for

1.3
1.7
1.8

im looking at better motorway use, cheers

ps, or alternative axels mgb etc.

[MarinaCoupe]

Saloon/Coupe/Estate
1.3 = 4.11:1 or late Ital 3.93:1
1.7 = 3.63:1
1.8 = 3.63:1

7cwt/440 Commercials = mostly 4.11:1 but some = 4.55:1

All 3.75" PCD

10cwt/575 Commercials = 4.55:1

4.5" PCD

MGB axles are 3.909:1 and entirely different, slightly narrower than Marina, and 4.5" PCD.

Dolly Sprint axle are entirely different again with 3.54:1 with 3.75" PCD. Also all brackets need cutting off and new ones welded one.

Chris

[locost_bryan]

All the small Triumphs shared the Marina diff (but not the axle housing). The 4.11, 3.89. 3.63 were also used in Spitfires and Dolomites, and a 3.27 in the GT6 and Dolomite 1850 auto. There are forum members who have fitted the 3.27 successfully.

[ClaytonSpeed]

Can someone confirm the 3.93:1 ratio and 3.89:1 and their fitments?

Ben

[MarinaCoupe]

Ben

3.93:1 was fitted to late Ital 1.3 saloons/estates and various Triumphs.

I'm not aware that the 3.89:1 was ever fitted to Marinas or Itals, it was fitted the Spitfire Mk4 and 1500, also Dolomite 1500. I think that the 3.89:1 diff will fit the Marina axle casing, but I don't know whether the splined section will match a Marina half-shafts. The 3.89:1 crown wheel and pinion can be bought new from Rimmers for about £300 and the fitted into a Marina diff.

[ClaytonSpeed]

That's what I thought Chris. Although I keep finding references to the 3.89 diff on many internet sites and nothing for the 3.93

[MarinaCoupe]

Who said the Internet was accurate? The web is worse than the proverbial man down the pub.

[ClaytonSpeed]

Obviously, but when you get 10 results with 3.89 and non for 3.93, you start asking questions..

[MarinaCoupe]

What search did you use?

[ClaytonSpeed]

Dolomite CWP

Morris Ital 1.3 Final Drive

[Kilroy]

At 4000 rpm the 3.27 would make a 400 rev difference over the 3.63
- that represents an extra gear.

It would make moving off slightly slower, but sounds very worthwhile for highway use.

[ClaytonSpeed]

Very true for a 1.7/2.0 or 1.8, but I'm looking at the 1.3. A little old A series may be asthmatic with a 3.27!

[MarinaCoupe]

For the difference between a 3.93:1 and a 3.89:1 you could adjust the performance by different tyre ratios.

[ClaytonSpeed]

True, But what was the 3.93:1 CWP also fitted too? Is it a real differential? Can you see it listed/documented anywhere?

[ClaytonSpeed]

Plus I'm starting with a 4.11:1 on the Mk3