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Aug 24th, 2023
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Joined: Jan 2012
Posts: 14,976 Likes: 1
Member of the Inner Circle
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Member of the Inner Circle
Joined: Jan 2012
Posts: 14,976 Likes: 1 |
Luckily for me my '76 came with 4.1 as standard 
Richard
1976 4/4 4 Seater
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Joined: Oct 2014
Posts: 5,016 Likes: 3
Charter Member
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Charter Member
Joined: Oct 2014
Posts: 5,016 Likes: 3 |
Crown wheel and pinion is 1200 €, plus at least 800 € for the conversion. That's a lot of money. The question is, is worth the money? So far the price has kept me away from changing... I'm going for a ECU upgrade first.
Hannes
once: Green M3W; 2013
now: Red 4/4 Sport; 2011
and some practical cars for use in real life
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Joined: Apr 2008
Posts: 11,856 Likes: 137
Scruffy Oik Member of the Inner Circle
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Scruffy Oik Member of the Inner Circle
Joined: Apr 2008
Posts: 11,856 Likes: 137 |
Crown wheel and pinion is 1200 €, plus at least 800 € for the conversion. That's a lot of money. The question is, is worth the money? In theory, you don't need a new crown wheel, just a new pinion gear with one fewer teeth
Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE
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Joined: Jul 2011
Posts: 1,948
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Jul 2011
Posts: 1,948 |
Crown wheel and pinion is 1200 €, plus at least 800 € for the conversion. That's a lot of money. The question is, is worth the money? In theory, you don't need a new crown wheel, just a new pinion gear with one fewer teeth For straight-cut gearsets, yes. But I thought helical gearsets had the pinion matched to the crownwheel and always needed changing in pairs otherwise the pitch/profile mismatch would cause the gears to eat themselves?
Stuart
"There's no skill substitute like cubic inches."
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Joined: Apr 2008
Posts: 11,856 Likes: 137
Scruffy Oik Member of the Inner Circle
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Scruffy Oik Member of the Inner Circle
Joined: Apr 2008
Posts: 11,856 Likes: 137 |
For straight-cut gearsets, yes. But I thought helical gearsets had the pinion matched to the crownwheel and always needed changing in pairs otherwise the pitch/profile mismatch would cause the gears to eat themselves? GPWM
Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE
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Joined: Dec 2011
Posts: 486
Learner Plates Off!
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Learner Plates Off!
Joined: Dec 2011
Posts: 486 |
Having driven Ice Packs 4/4 and mine back to back, our mogs were neck to neck on acceleration I only gained a nose as I could hold the gears longer.
Ice Packs had the gear set change mine ECU remap on driving Ice Pack it felt flat and gutless but went like stink, mine felt like a bigger engine.
As a road mod I don't think I could live with it on long journeys as the rev's in 5th would be to high at motorway speed.
4.10 ratio 5 gear
2000 RPM 48.4 mph
2500 RPM 60.5 mph
3000 RPM 72.6 mph
3500 RPM 84.7 mph
4000 RPM 96.8 mph
3.73 ratio 5th gear
2500 RPM 66.5 mph
3000 RPM 79.8 mph
3500 RPM 93.1 mph
4000 RPM 106.4 mph
But as a B road Street racer it would be a blast.
The real answer for the road use is torque and BHP.
Cain
Wolf Cafe Racer
4/4 Sport
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Joined: Aug 2014
Posts: 265
Learner Plates Off!
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Learner Plates Off!
Joined: Aug 2014
Posts: 265 |
How can I check the gear ratio that is on the rear axle? You can work it out using this tool: www.performanceprobe.com My handbook said 3.73 but I actually had a 3.91 final installed. e.g. Mazda ratios from: 1st 3.136 2nd 1.888 3rd 1.330 4th 1.00 5th 0.814 Put in your tyre sizes and change the ratios for the diff. Then compare with the MPH/KPH to RPM in your car.
Looking for another Morgan!
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Joined: Sep 2009
Posts: 7,342 Likes: 91
Talk Morgan Guru
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Talk Morgan Guru
Joined: Sep 2009
Posts: 7,342 Likes: 91 |
Gulf44, thanks a lot, I must double check, but I'm rather sure that my 2014 4/4 also is equipped with a 3.9 rear axle comaparing the calculation with an acceleration video I have made.
'14 4/4 graphite grey
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Joined: Apr 2008
Posts: 11,856 Likes: 137
Scruffy Oik Member of the Inner Circle
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Scruffy Oik Member of the Inner Circle
Joined: Apr 2008
Posts: 11,856 Likes: 137 |
As a road mod I don't think I could live with it on long journeys as the rev's in 5th would be to high at motorway speed.
<snip>
But as a B road Street racer it would be a blast.
The real answer for the road use is torque and BHP.
I kind of agree, Cain, after 3 hours on a motorway at 80mph+ mine can be a bit wearing (although it's the wind blast that's more tiring that the revs) - but it's more than compensated for when you get off, and after all, who buys a Morgan to drive on motorways? They are just a necessary evil to be endured whilst getting to the fun bits...
Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE
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Joined: Mar 2009
Posts: 2,255 Likes: 2
Talk Morgan Expert
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Talk Morgan Expert
Joined: Mar 2009
Posts: 2,255 Likes: 2 |
Tim,
At that speed mine is turning over at 3000 rpm in fifth. Does that sound like 3.73?
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