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SORN
by OldSkrote - 31/07/25 02:07 PM
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New
by Rex_tulips - 30/07/25 07:59 PM
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Forums34
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Most Online1,046 Aug 24th, 2023
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Joined: Apr 2008
Posts: 11,874 Likes: 138
Scruffy Oik Member of the Inner Circle
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Scruffy Oik Member of the Inner Circle
Joined: Apr 2008
Posts: 11,874 Likes: 138 |
with my 2005 PLUS 4 with the 80km/h and former 90 km/h speed limitation in France I found that 5th gear at 2200 rpm is too low and I generaly use the 4th (2500/2900 rpm). Sport cars must have short and close ratios. 3000 rpm is half of the maximum rev and doesn't stress the motor. If you always use low rev your motor will stay lazy with poor accelerations and cannot get its full nominal power.
It sounds to me like you have the 3.7:1 rear differential, which does tend to make for more of a tourer rather than a sports car feel. TBM (and I) have 4.1:1 diffs, which keeps things lively, even with the .84 ratio 5th gear you're still doing 3000 rpm at 70mph. On minor roads like you I'm in 4th gear more often than 5th.
Tim H. 1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE
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Joined: Dec 2011
Posts: 374
Learner Plates Off!
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Learner Plates Off!
Joined: Dec 2011
Posts: 374 |
I have the 3.73:1 ratio which is too low. A 4.1:1 or 4.33:1 will be better for my PLUS 4.
Regards 2005 PLUS 4
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Joined: Jul 2007
Posts: 28,432 Likes: 182
Salty Sea Dog Member of the Inner Circle
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Salty Sea Dog Member of the Inner Circle
Joined: Jul 2007
Posts: 28,432 Likes: 182 |
Phil, If you can get it done at a reasonable price (bearing in mind things like modification to propshaft and possibly trans tunnel) then go for it. Had I done the same to my '76 I'd probably still have that car. 
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '09 Gen2 MINI Cooper ragtop '90 LR 90 SW
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Joined: Nov 2018
Posts: 6,063 Likes: 161
Talk Morgan Sage
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OP
Talk Morgan Sage
Joined: Nov 2018
Posts: 6,063 Likes: 161 |
Yeah, the quote I've had is a lot of money (for me) but very good value for the amount of work and parts that are needed.
I'm going to start putting some cash aside and sell off some bike stuff, and hopefully will have got close early in the new year.
1972 4/4 4 seater, 1981 MGB GT 1984 Harley Davidson Electra Glide, 1990 Kawasaki ZX10
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Joined: Feb 2019
Posts: 309
Learner Plates Off!
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Learner Plates Off!
Joined: Feb 2019
Posts: 309 |
I'll be keeping an eye out for your progress on that TBM. I'm thinking of the same thing but doing it myself (apart from the welding). I need to do the Paint first but I do miss the overdrive ratio that I have on my MGB.
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Joined: Nov 2018
Posts: 6,063 Likes: 161
Talk Morgan Sage
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OP
Talk Morgan Sage
Joined: Nov 2018
Posts: 6,063 Likes: 161 |
I'll stick details up once it's underway. It's not beyond the skill of a competent DIYer. My issue is I only have a small front drive to work on (the car just fits, and then it's the pavement!) I also have to clear everything away at the end of the day so would be almost impossible at home.
By the time I'd hired an garage space for a few days, and an engine hoist, and then transported all my tools there and back, I'd probably be several hundred quid into it before I'd even turned a spanner, sp no option but to pay to have it done.
1972 4/4 4 seater, 1981 MGB GT 1984 Harley Davidson Electra Glide, 1990 Kawasaki ZX10
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Joined: Feb 2019
Posts: 309
Learner Plates Off!
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Learner Plates Off!
Joined: Feb 2019
Posts: 309 |
That's understandable. Would probably do the same in those circumstances. Although I did once change the gearbox in my Mk.1 Escort on the side of the road!
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Joined: Sep 2015
Posts: 145
L - Learner Plates On
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L - Learner Plates On
Joined: Sep 2015
Posts: 145 |
The 4 speed and the 5 speed gearboxes are not necessarily the same ratios. The standar ratio use for first in the 4 speeds was 2.97 where most of the 5 speed T9s run 3.65 in first. You can swap the gear sets to match the long first gear of the 4 speed (my preference). I don't really use 5th under 70mph. For how you describe your driving I don't know why you'd bother.
'61 +4 DHC '70 4/4 '80 4/4 4seater
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Joined: Apr 2008
Posts: 11,874 Likes: 138
Scruffy Oik Member of the Inner Circle
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Scruffy Oik Member of the Inner Circle
Joined: Apr 2008
Posts: 11,874 Likes: 138 |
The 4 speed and the 5 speed gearboxes are not necessarily the same ratios. The standar ratio use for first in the 4 speeds was 2.97 where most of the 5 speed T9s run 3.65 in first. You can swap the gear sets to match the long first gear of the 4 speed (my preference). I don't really use 5th under 70mph. For how you describe your driving I don't know why you'd bother. I'd agree with having the higher ratio 1st gear, it definitely improved my box, but I wouldn't say 5th is useless under 70mph, it makes for a very relaxed bimbling gear - always assuming the engine is making enough power to pull it, of course.
Tim H. 1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE
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Joined: Nov 2018
Posts: 6,063 Likes: 161
Talk Morgan Sage
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OP
Talk Morgan Sage
Joined: Nov 2018
Posts: 6,063 Likes: 161 |
Just had a scan and you're right, I have the 1600GT so if the GT box is fitted it will be a 2.97 first. Spend so little time in first I don't think I'll notice. Not into roaring away from the lights - as I said, I have bikes that fulifl my 'need for speed'.. The most important reason I'd not mentioned is to stop the gear lever rubbing on my leg. Third is fine, 4th rubs.  But seriously, I woul rather bimble along at 60 at 2500rpm than 3100rpm. Less strain on the engine, quieter, less fuel used. Also I will be able to drop her down a cog and let her go if needed.
1972 4/4 4 seater, 1981 MGB GT 1984 Harley Davidson Electra Glide, 1990 Kawasaki ZX10
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