Japanese gear box better?

[TRnorwegian]

I'm a rookie on the TR-arena, but I have noticed that some TR6'es seem to be fitted with gearboxes and/or differentials from Japanese cars.
Since I suspect my gear box will need much work (a grinding/scraping metallic sound occurs when accellerating), I wonder if it would be worth investigating alternative options rather than overhauling my excisting box (which BTW doesn't have OD).
Which treads can I follow to find out more about such modifications? Are these japanese boxes compatible with the original? Much work involved?

 

[TR3driver]

Opinions vary, here's mine.

The main advantage of the Japanese conversions is that it allows incorporation of an overdrive (5th) gear without the expense of sourcing and/or rebuilding an original overdrive.

The original boxes are not particularly fragile or troublesome; but after 25-50 years they are a bit 'tired'. Used parts in good condition are getting scarce (hence expensive) and new parts (when they are available) tend to be rather expensive due to the limited market for them.

By contrast, used examples of the Japanese version are plentiful and cheap.

There are 3 conversion paths that I know of :

1) Herman van den Akker offers a kit of parts that you use to convert a Japanese box that you can source locally. This kit includes a custom cast bellhousing, so is rather expensive. Search the forum for HVDA, you'll find lots of happy customers. https://www.hvdaconversions.com/pgs-final/ordering-info-contact.html

2) There is a club over in Arizona doing a lower cost conversion, but an original gearbox gets sacrificed in the process. I don't know how practical it would be to get one of these shipped to Norway, but the main thread is at
https://www.britishcarforum.com/bcforum/ubbthreads.php/topics/517649/Tr3_club_Toyota_conversion

3) Company in New Zealand is offering a conversion, but all I know is that they want to ship the entire unit to you (including the heavy gearbox).

Personally, having a Toyota drivetrain under a Triumph skin doesn't appeal as much to me. An A-type OD gives you a 7 speed semi-automatic, which can be a lot of fun on a mountain road. But I have no problem with others who go the Toyota route ... leaves more Triumph parts for me !

 

[TR6oldtimer]

Quantumechanics offers a complete, ready to install unit for $3,275 +shipping.

https://www.quantumechanics.com/categories.php?op=newindex&catid=7

 

[Geo Hahn]

I went with the OD from Quantumechanics with feelings similar to those expressed by Randall.

But if you are located in Norway the shipping might be a problem ($$$). I'm thinking that OD w/gearbox weighs about 85 pounds.

I was thinking someone (possibly in the UK) was doing a 5-speed conversion with a Ford tranmission. Given your location that might be attractive.

 

[BobbyD]

My only comment/concern with the Ford 5 speed is why did Moss pull it as a product in less then a year? Was it quality, price, lack of sales? A company the size of Moss doesn't just add products like that without a lot a research so for them to pull it so quickly makes me wonder........ I went the Toyota route.....along with a few other mods over the years.

 

[SteveTR]

Everyone has an opinion here. This thread is also over on the MG side. People have their preferences.

I vote for Bill Close in Arizona. He does quality work whether you live in Norway or Northern California.

He can be reached at (480) 835 - 0987. Bill's address is 3047 E. Nance, Mesa, AZ 85213.

I have no connection with Bill outside of friendship.

Good luck...

Cheers,

 

[PeterK]

Toyota 5-speed, Toyota 4-pot calipers, Datsun Z finned rear drums, Morgan rear wheel cylinders on my TRs. All bolt-on (bolt-off) reverseable mods.

If I had an IRS, I would probably use the Nissan LSD too.

 

[prb51]

Regardless of your choice having the longer legs of a 5th gear/overdrive is almost essential here in the States. I regularly drive on 70 + mph roads where everyone in driving 10 mph over the limit. Way too many rpms for a 4 gear box for any long period ( I regularly drive 200 plus miles just to get to a friends house).
I went for simplicity/ease of maint and the Toyota 5 speed. The original OD is a great item too especially with the od on the other gears but was more than I wanted to spend and can be maint. prone because of their age and 50 year old technology (and the leak).
If I drove shorter distances and less miles I'd go with the original OD as it is correct and a cool piece of work. I erred on the side of maint. free.

 

[emmett1010]

Hi Guys;
Don't want to start a new thread, but having worked for
Volvo in the late 70's I alwas liked their OD.

Is the Volvo OD, a viable option? If so what modifications are necessary?
Thanks, Emmett

 

[TR4nut]

There are 3 conversion paths that I know of :

Not sure if this is a 4th option, but it is closer to Norway: I think Moss Europe has a conversion option as well.

 

[tdskip]

I think Ford Sierra boxes are popular in Europe as well, should be freely available. The box itself is very well regarded, but I can't speak for how well it worked in practice so I'd look into Bob's observation carefully.

In any case - use a kit from someone with a good reputation for support!

Robsport and others also have options, and of course find out what your local club says.

 

[kodanja]

I have the Ford type 9, 5 speed in my 69' TR6.

I love it, the ratio is not quite as good as the Toyota.
I have heard many good things about the Toyata conversion.

Mine was the very 1st one that John at Quantum Mech. installed and although I blew a clutch plate,
John assured me that it was a manufacturers defective clutch.

I average approx. 75 mph at 3300 rpm's, I am very pleased with the type 9'!!!!!

 

[TR3driver]

Hi Guys;
Don't want to start a new thread, but having worked for
Volvo in the late 70's I alwas liked their OD.

Is the Volvo OD, a viable option? If so what modifications are necessary?

Emmett, AFAIK Volvo always used Laycock overdrives, as did Triumph; so effectively they are the same thing. Late 70s would be the J-type; earlier Volvos used A-types. Not sure just when the change point was for Volvo, but no later than 1973 I think. In fact, many if not most of the "TR6" overdrives sold on eBay actually came from Volvos (and lots of folks have been tripped up by the relatively minor differences between actual TR6 and Volvo units).

So, adding a Volvo OD is pretty similar to adding a Triumph OD; still have to deal with adapters, mainshafts, lockout switches, angle drives, etc. In addition the speedometer pinion gear needs to change; in some cases the driving (spiral) gear inside needs to change as well. Also a Volvo OD may not have the holes drilled and tapped for the TR6 rear mount. Need a Triumph rear flange too, I don't believe the Volvo flange will match (and the J-type takes a different flange than the non-OD gearbox).

 

[TR3driver]

I average approx. 70 mph at 3300 rpm's, I am very pleased with the type 9'!!!!!

Why so high? Isn't 5th gear an overdrive? With stock tires, diff & Triumph overdrive, you would be turning only about 2800 rpm @ 70 mph.

 

[kodanja]

nonsence

 

[prb51]

I have the Ford type 9, 5 speed in my 69' TR6.

I love it, the ratio is not quite as good as the Toyota.
I have heard many good things about the Toyata conversion.

Mine was the very 1st one that John at Quantum Mech. installed and although I blew a clutch plate,
John assured me that it was a manufacturers defective clutch.

I average approx. 75 mph at 3300 rpm's, I am very pleased with the type 9'!!!!!"

Isn't that a tad off, what diff ratio do you have?
3300 rpm in my TR3 w/Toy 5speed equals about 86 mph. The 1 to 1 4th gear (same as stock) would be 67 mph so you are gaining only 8 mph? I know it's a dif TR but the stock trannies are about the same.

 

[kodanja]

well someday Ill actually get my speedo to work! :hammer:
Then I can see for sure......

But I did say ((approx.))

better yet,
next drive Ill have my wife follow me in her car and let me know when I hit 70'


Ill let ya know'

 

[PeterK]

better yet,
next drive Ill have my wife follow me in her car and let me know when I hit 70'

That's how I verified mine - only it was my brother following me, not your wife!

With my Supra HVDA, 5th gear 70mph=2700rpm, 60mph=2300rpm.

 

[kodanja]

lol' :banana:

next dry day Ill do it'

 

[prb51]

You can do the same thing with a GPS if you can get one. It will give you your mph...better than handling a cell phone and watching your speedo.
Another way is this

https://www.teammfactory.com/gearcalculat...amp;trannytype=

If you know the ratios in your box, wheel size and differential you can calculate approx speed (actually exact speed minus drag/cohesion/wind etc) so it really is approx especially at the higher end.

The numbers shown are for my Toy 5 speed box/tires/diff