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Nissan vs Mazda vs mgb mk11 4 speed O/drive

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olbrowneye Paul Brown
Goulburn, NSW, Australia   AUS
Looking to replace in my 1966 mgb roadster, the mk11 full synchro 4 speed mgb gearbox with either the Nissan 5 speed or the Mazda 5 speed. I’m guessing there’s plenty of blokes out there that’s done the conversions, I know as been quoted around $5,800 au, for the Mazda 5 speed kit & about $1,100 au to be installed hmmmm ! .
I know of the Nissan 5speed box being installed! What other parts do I need for the conversion? No idea at this stage of cost .
Or do I go with the original 4 speed overdrive mg box for sale in South Australia for $1200, ? will the drive shaft be the same or do I need to change it ? Electrics ! Apart from the o/drive switch which I have, is there a wiring loom that I need to purchase, wadda you’s Reckon would be the better option apart from the Mazda kit, budgeting restraints.
Cheers olbrowneye

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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
7 grand to install the wrong transmission!? Get the MG OD one... they're great... and you get 6 speeds. I rebuilt mine last year after it had done 120,000 miles. Works like new with a few new bearings and a layshaft. Quite easy to work on.

Adrian



Home built Eaton M62 Supercharger with 7.6psi boost, 8:1 compression, custom "supercharger" cam from Schneider Cams, Mikuni HSR48 Carburetor, Chevy Cavalier 1.6 rocker arms, Maxspeeding rods with Teflon wrist pin buttons, custom aluminum cold air intake, CB Performance computerized ignition, Fidanza 9 pound flywheel, 1.44 exhaust valves in 48cc chamber head, matched manifolds, 2 1/4" exhaust system.

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Pointe Claire, QC, Canada   CAN
Hi,
Last year I installed a 5 speed transmission kit from Moss Motor. I believe it is a Ford T5.
The kit came with the speedo cable, a new cross member, and shifter. It fit right in with no fuss. I was running at 3900 rpm while driving at 105 kpn ( 65 mph).
The car now runs at 2800 rpm at the same speed.
It works well.

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Bernd Kamenicky Avatar
Bernd Kamenicky Bernard Kamenicky
Altlengbach, Lower Austria, Austria   AUT
1966 MG MGB GT "The Red One"
1971 MG MGB MkII "The Blue One"
Dear Paul,
you will get all answers from "maintain originality and sray with original O/D at low cost" over "T9 is best and cheapest conversion" up to "Matzda G/B shifts best"
So I give you my personal experience with O/D and Mazda G/B: I own 2 MGBs a '71 convertible (4sync gear&O/D) since 1992 and a '66 GT (3sync gear&O/D) since 2007 both with highly modified street engines.
I have overhauled a couple of original gearboxes and O/Ds so far and I love the original MGB gearboxes although the 3 sync is a bit on the weak side but I enjoyed shifting into 5th and 6th gear by just flicking a switch.
On the '71 the switch is on the right (wiper) stalk so you even have a sghift paddle feeling.
So much for the original O/D.
However, availability of parts ( 1st gear, 2nd gear sync, layshaft, reverse idler, mainshaft....) and awkward handling of the 3 sync and a bad (unavailable) mainshaft and planetary gear set of the O/D on the 4 sync G/B made me make up my mind away from originality towards more modern and rigid gear design.
Knowing the Mazda MX5 gearbox from a girl-friends car I ordered a Mazda gearbox conversion kit from Vitesse at MOSS Europe for my '66 GT.
Being a narrow tunnel car it refused the acceptance of the Mazda conversion without modifications so I did grind away a part of the flange and cut out about 5 mm of the back side of the lower tunnel under the black cover plate where the gear shift lever enters the interior. See pics. I did NOT move the engine forward as initially adviced by Vitesse becaus this would have made my pulley with torsional vibration damper foul the steering rack.
Result: an amazing difference in driving experience: Smooth and even shorter shifting, perfect synchronisation (though I CAN double clutch!!) and the knowledge that torque and power of an MGB 4 cyl. engine by far will not exploit this gearboxes capability. For some sad things happening to my Audi the GT was daily driver to work from August to November w/o problems.
In the meantime I have ordered a 2nd Mazda 5 speed conversion kit directly at Vitesse for my'71 B for 2300 Pounds before they start their BREXIT.
Hint from my side:
If you decide for the Mazda G/B you should order a narrow tunnel kit as your car will probably have narrow tunnel even if you could install MK2 gearbox.
I talked to Alec Poole (Sales Mgr of Vitesse yesterday) and shared my installation experience on the MK1 GT. He told me that initially they had an MK1 car without damper so the moved the engine forward. Not doing this meant grind away some 10mms from the flange and cut the tunnel - exactly what I did.
Lately however, they have shortened the flange by 8 mm in length so the Mazda G/B will fit to narrow tunnel cars without having to cut the lower tunnel or moving the engine forward.
Due to unavailability of Nissan G/B in Austria for good price I cannot comment on that.
Whatever you decide: All the best & Cheers
Bernd


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olbrowneye Paul Brown
Goulburn, NSW, Australia   AUS
Thanks mate the overdrive is looking a cheaper option for me for sure providing it’s as good as they say it is & like you say 6 speeds.
Did you hav’ta change drive shafts, ? & what electric’s did you hav’ta purchase?
The motor came out to bolt gearbox together?
Cheers � Paul

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tvrgeek Avatar
tvrgeek Scott S
Hillsborough, North Carolinia, USA   USA
1965 MG MGB
Just completed a Nissian 5-speed for about 2K US. Of course, I did the install myself. I already had a gear reduction starter. Very happy with the results. On a Mk 1, I had to spread the tunnel a little, pound in the footbox on the left side just a bit, and remove/replace the rear drive shaft safety plate a little to clear the fatter driveshaft. Then did a new tunnel cover as the shifter needs a little more space to the right for 5th and reverse and it is a tiny bit further forward.



Cogito ergo sum periculoso


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olbrowneye Paul Brown
Goulburn, NSW, Australia   AUS
Thanks Bernd & thanks for the photos it’s giving me a few ideas and options to go with !
I like the idea of keeping originality apart from a later o/drive box, but like the idea of a good mechanical Japanese trouble free 5 speed
Box. Thanks for taking the time in furnishing me of your experience cheers mate �
Paul Olbrowneye

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Perdido Avatar
Perdido Gold Member Rut Rutledge
Tuscaloosa, AL, USA   USA
Paul,
I changed out my 4 speed for an OD in my 70 B and it cost about $500 US all in with me doing the work. I also did a Datsun 5 speed conversion on my 60 bugeye and it’s nice, but would I do it again? I really like to work on these cars and I like to drive them too, but how much improvement will it do for my driving experience? I guess if I did more high speed highway driving I would appreciate my conversions more. Give it some thought based on how and where you drive and do you think it will give you more grins per mile.
Rut



1960 Bugeye undergoing restoration, 1275
1970 MGB, Pale Primrose
1967 Triumph TR4a
1966 Triumph TR4a
When I went to school, they asked me what I wanted to be when I grew up. I wrote down 'happy'. They told me I didn't understand the assignment, and I told them they didn't understand life. John Lennon

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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
I think you'll find the general consensus is that the MG OD transmissions are pretty much bomb proof.

Adrian



Home built Eaton M62 Supercharger with 7.6psi boost, 8:1 compression, custom "supercharger" cam from Schneider Cams, Mikuni HSR48 Carburetor, Chevy Cavalier 1.6 rocker arms, Maxspeeding rods with Teflon wrist pin buttons, custom aluminum cold air intake, CB Performance computerized ignition, Fidanza 9 pound flywheel, 1.44 exhaust valves in 48cc chamber head, matched manifolds, 2 1/4" exhaust system.

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Bernd Kamenicky Avatar
Bernd Kamenicky Bernard Kamenicky
Altlengbach, Lower Austria, Austria   AUT
1966 MG MGB GT "The Red One"
1971 MG MGB MkII "The Blue One"
Dear Paul.
what I forgot to say: Lowering the engine speed in an MGB REALLY matters. It's so much more pleasant to drive even on the road. I usually drive highways and on my tours to Romania, Italy, Croatia aso I really collect miles.
I could not imagine being back in the old days before I changed from 4 speed to O/D in 2002.
A 4 sync O/D gearbox is of course the cheapest option and I still would employ mine but mind you that it must be in good order. Main shafts are not or at least scarcely available and before installing I would dismantle and check all needle bearing raceways on all shafts (main, layshaft) and change 2nd gear synchro rings. Changing all bearings and O-Rings and Seals would be a good thing to do but you' ll soon have spend 300 Euro. Also check O/D annullus, you'll surely find pitting on the gear teeth but as long as it stays < 10% of the area it is not frightening.
I had bad luck with a planetary gear bearing damaged leading to misalignment of annullus and planetary gears and O/D disengaging under load (that's how I realized). A lot of hardened iron chips from the annullus teeth spread around in the whole gearbox and killed the needle bearing raceway on the main shaft. Not available in UK, cost in germany: 800 Euro! Overhauled O/D and gearbox at MOSS Europe (no return of old items possible for my damaged units) would be about 1600 Pounds. That's why I decided to add further 700 Pounds and have a brand new (though japanese) gearbox.
The Mazda kit comes with mounting bar (to avoid the original one), prop shaft, new coupling, new slave cylinder (alone what a pleasure to bleed compared with the OE) and speedo cable with angle drive.
And it's a completely reversible thing with no changes to the body.
Another question from your side yet to be answered:
If converting your '66 MK1 car to O/D you'll need a switch in the dash, a corresponding O/D wiring harness (FUSE IT SEPARATELY!!!!!!) and depending on axle a new propshaft.
As you use 4 sync G/B I assume you also use tube axle so I also assume you have already a propshaft of 31 1/8 inch (78,9cm) length. This you can keep for O/D. If you have 30 or 32 inch Prop shaft you need to change (refer to MOSS catalogue).
Cheers, mate
Bernd

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ingoldsb Avatar
ingoldsb Silver Member Terry Ingoldsby
Calgary, AB, Canada   CAN
1971 MG MGB
In case no one else answered your question - there is no need to change driveshafts - they are the same for OD and non-OD.

I'm sure a modern gearbox is technically a better choice, but for cost and ease of installation, the OD is the clear winner. The OD works great. It is kind of 5 and half speeds. Third gear OD is very close to fourth gear non-OD.

So, if you are rowing through the gears on a race course, a real 6 speed gearbox is probably an advantage over the OD. If you are just driving the car as a street driver, the OD is completely sufficient.

And - once you have the OD, you can join the debates about the ideal lubricant (which, as all reasonable people know, is Redline MT-90) smiling smiley



Terry Ingoldsby
terry.ingoldsby@DCExperts.com

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Idasix Avatar
Idasix Gold Member David Smailes
Mount Vernon, WA, USA   USA
1975 MG MGB "Red Rider"
I installed the Rivergate 5 speed in my car about 5 years ago. Was super easy and I din't have to modify a single thing in the car. I was sent a new flywheel and speedo stuff. Have to send back the old flywheel as a core. No cutting of tranny tunnel etc. Went in smooth and works great. ALL parts were included except the tranny. Found one very fast and it had already been rebuilt.

My mechanic did the Mazda route for a customer. He said it was easy as hell. He thought the Mazda was a better way to go simply because it's a part that is regulary stocked on dealers parts shelves the Nissan is not. Anyway I am glad I did it.

Dave



The brave don't live forever...
The cautious don't live at all.

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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
I had bad luck with a planetary gear bearing damaged leading to misalignment of annullus and planetary gears and O/D disengaging under load (that's how I realized). A lot of hardened iron chips from the annullus teeth spread around in the whole gearbox and killed the needle bearing raceway on the main shaft.


Almost certainly due to installation of the planetary gears out of phase by whoever was in there last.

Inasmuch as the 66 in question has already been converted to a 4-synchro gearbox, the same drive shaft can be used.

For reference, the MGB LH overdrive affords an 18 percent reduction in engine speed for a given road speed.

Dick






In reply to # 3907318 by Bernd Kamenicky Dear Paul.
what I forgot to say: Lowering the engine speed in an MGB REALLY matters. It's so much more pleasant to drive even on the road. I usually drive highways and on my tours to Romania, Italy, Croatia aso I really collect miles.
I could not imagine being back in the old days before I changed from 4 speed to O/D in 2002.
A 4 sync O/D gearbox is of course the cheapest option and I still would employ mine but mind you that it must be in good order. Main shafts are not or at least scarcely available and before installing I would dismantle and check all needle bearing raceways on all shafts (main, layshaft) and change 2nd gear synchro rings. Changing all bearings and O-Rings and Seals would be a good thing to do but you' ll soon have spend 300 Euro. Also check O/D annullus, you'll surely find pitting on the gear teeth but as long as it stays < 10% of the area it is not frightening.
I had bad luck with a planetary gear bearing damaged leading to misalignment of annullus and planetary gears and O/D disengaging under load (that's how I realized). A lot of hardened iron chips from the annullus teeth spread around in the whole gearbox and killed the needle bearing raceway on the main shaft. Not available in UK, cost in germany: 800 Euro! Overhauled O/D and gearbox at MOSS Europe (no return of old items possible for my damaged units) would be about 1600 Pounds. That's why I decided to add further 700 Pounds and have a brand new (though japanese) gearbox.
The Mazda kit comes with mounting bar (to avoid the original one), prop shaft, new coupling, new slave cylinder (alone what a pleasure to bleed compared with the OE) and speedo cable with angle drive.
And it's a completely reversible thing with no changes to the body.
Another question from your side yet to be answered:
If converting your '66 MK1 car to O/D you'll need a switch in the dash, a corresponding O/D wiring harness (FUSE IT SEPARATELY!!!!!!) and depending on axle a new propshaft.
As you use 4 sync G/B I assume you also use tube axle so I also assume you have already a propshaft of 31 1/8 inch (78,9cm) length. This you can keep for O/D. If you have 30 or 32 inch Prop shaft you need to change (refer to MOSS catalogue).
Cheers, mate
Bernd



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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danthefitman Avatar
danthefitman Dan The Fitman
Portland, OR, USA   USA
1979 MG MGB MkIII "Simply, A Great B!"
I'd never done any sort of engine, gearbox swap or work before until 2010. I bought a 77 B in Fall of 2009. And February of 2010 and began my work. The job was to swap gearboxes as the 77 had an original Late Model blue label OD gearbox. I pulled two engines and gearboxes, and swaped the gear boxes. When I met John Twist in summer of 2012, he said that my engine number originally had a corresponding overdrive gearbox. Someone put a 1969 4 speed gearbox in my 79 MGB at one point years past. Did lots of R&R and might as wells. I even took the side plate off the OD, and smoothed out the reverse teeth with my Dremel tool, because the DPO, was forced to get into reverse because the roller throwout type bearing had mostly exploded on the shaft and was barely working. The previous DPO, had put 90 weight gear oil in the gearbox and had a roller type throwout bearing. Not the graphite original solid type.

Result has been beautiful. It's been 9 years and my OD gearbox has never given me one iota of trouble. I put 20 50 Castrol in of course. And a new overdrive switch. And I always clutch when I use the switch I don't just use the switch. I baby my OD, and I've already changed the oil once since 2010. It probably has around 5,000 miles on it since I did the OD switch.

I bought that white 77 in the fall of 2009 for $1,200. In summer of 2010 I sold it for $3,200 with the 4-speed gearbox in it. So the cost of the OD gearbox, was free. I more than made up for the cost of the original purchase of that 77 B in Fall of 2009, I came ahead. And I learned a ton.

I did a lot of might as wells in that car, so the guy that got it got a good car. It had no rust, a really nice interior, a strong engine and everything worked well. I even got the windshield replaced, and a guy did it for $200. He had to do it twice, and he shook his head so much after having done it his head almost fell off his shoulders! He said he should have charged me $500.



1st Place Winner ABFM Portland Oregon 2008, 2010, 2011, 2012, 2013, 2014, 2015 & 2016!
Email me for questions or needs, I'll respond promptly! dan@allpointsorganized.com
Life. Positively in order.



Edited 6 time(s). Last edit at 2019-03-12 11:47 AM by danthefitman.

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Be Coming Avatar
Be Coming Kelvin Dodd
So. Calif., USA   USA
Since the car has already been modified to fit the 4 synchro transmission, I would go for the over drive. It's an MG thing. You can drive any 5 speed equipped econobox, but there are only rare cars that allow you to engage overdrive at the flick of a switch.

My unmodified 1967 GT is getting a T9 5 speed with a modified original shift knob as I like the way the shifter feels.

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