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tips, technology, tools and techniques related to vehicle driveline components

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minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

RV8 gearbox swap
Posted by: minorv8
Date: October 21, 2019 01:24AM

A new project for my toy. The plan is to replace the LT77 with something more modern. I fitted the LT77 about 20 years ago. It had unknown mileage and was originally in a TR7. Basically the weakest version of them all. I rebuilt it and it has provided reliable service all these years behind a healthy 4.6 litre engine.

Anyway, updates to follow...


Loota_1.jpg


minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: RV8 gearbox swap
Posted by: minorv8
Date: October 23, 2019 01:58AM

I got a donor bellhousing from UK, a later model automatic version. I only needed the flange so I cut about 3 inches wide rim of the bellhousing. This engine will still run a LT77 box but whilst I had some internals balanced I had the flywheel redrilled for a Sachs clutch bolt pattern. I fitted it on the flywheel to get some measurements for the new gearbox fitment.



Leikelty kytkinkoppa.jpg


Kytkin.jpg


MGBV8
Carl Floyd
Kingsport, TN
(3829 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB, Buick 215

authors avatar
Re: RV8 gearbox swap
Posted by: MGBV8
Date: October 23, 2019 09:29AM

I thought that the R380 would be a direct swap & more stout.


minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: RV8 gearbox swap
Posted by: minorv8
Date: October 23, 2019 03:14PM

I do have a R380 and it both is and is not a direct swap. Yes, the bellhousing fits but the V8 type release bearing carrier did not. At least not with my clutch. The pivot pin boss is taller too. I'll post a pic tomorrow. Also, the ratios are exactly the same as LT77 and I wanted different ratios. Rear support is further back and requires a different crossmember.

The new box is a GS6-37-DZ 6-speed from a BMW diesel. First gear is useless but rest of the gear ratios suit my needs better. Local turbo tuners have put over 500 lb ft thru these boxes and I doubt that my engine will ever produce such numbers. Using a BMW clutch gives a much more options than Rover does.



Edited 1 time(s). Last edit at 10/24/2019 01:45AM by minorv8.


minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: RV8 gearbox swap
Posted by: minorv8
Date: October 24, 2019 02:18AM

Here is a photo of the R380 front cover plate. Two major points of interest: yellow arrow marks the release bearing arm pivot point. Itīs roughly 1/2" taller than LT77. Red arrow shows the general shape of the cover plate. It is also more robust than LT77 one.

Normal SD1 V8 release bearing carrier did not fit between the diaphragm and cover plate (McLeod items). Also the pivot boss+pin height means that you canīt fit the slave cylinder. It wonīt reach the bellhousing.

The easy fix is to machine the pivot pin boss down and shorten the release bearing carrier. But this means that it is not a direct swap. How much to machine ? Hard to say but if you take measurements from LT77 one should be close enough.


R380.jpg


roverman
Art Gertz
Winchester, CA.
(3009 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: RV8 gearbox swap
Posted by: roverman
Date: October 24, 2019 11:00AM

Borg Warner T5 too hard to get ?


minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: RV8 gearbox swap
Posted by: minorv8
Date: October 24, 2019 02:03PM

I haven't checked lately but they tend to be pricy. Escpecially if they are WC ones. The bellhousing may prove difficult to source though. And expensive... I only paid 150 $ for this box, including shipping. 100 $ for the bellhousing, again including shipping.



minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: RV8 gearbox swap
Posted by: minorv8
Date: December 02, 2019 05:10AM

So, here is the end result. Two inch rim of the auto bellhousing, shortened BMW bellhousing and some aluminum sheet to reduce the diameter.


Converted box.jpg


MGBV8
Carl Floyd
Kingsport, TN
(3829 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB, Buick 215

authors avatar
Re: RV8 gearbox swap
Posted by: MGBV8
Date: December 02, 2019 10:29AM

Very nice!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5868 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: RV8 gearbox swap
Posted by: BlownMGB-V8
Date: December 02, 2019 01:18PM

I like seeing these sort of adaptations. Be mindful of your runout both concentrically and radially or at right angles to the driveline. +-0.010" is generally acceptable but the closer you can get it the better. I usually shoot for +-0.001"

Jim


minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: RV8 gearbox swap
Posted by: minorv8
Date: December 03, 2019 12:30AM

Yes, these conversions are done with a rigid adapter that registers in the gearbox casing. IN the other end, it centers into the main bearing bores. Finally after welding the casing flange is machined at 90 degrees. So, it should be pretty close. How identical the block dimensions are, that is another question :-)



Edited 1 time(s). Last edit at 12/03/2019 12:31AM by minorv8.


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