I have a 1967 B10 Historic Rally Car that has been quite successful over some years but now I have a problem with the gear ratios. The rules the car was built to required the use of the FIA homologated engine block and gearbox(my car came with a 3 speed but I changed it to the FIA homologated 4 speed) I would like to find a higher ratio diff, I currently use a 1:4.375 from the VB10 but have heard of a 1:4.625 existing.

I ended up in this position because I found a lay shaft from a sports option gear set for a 4 speed close ratio with the following ratios, 2.862, 1.908, 1.350 ans 1.000 for 4th. The sports option parts are listed in a 12/1969 B10-T KB10 Sport Options Parts list which I picked up from somewhere. These ratios might sound familiar as I beleive they are the same as the top 4 ratios on the 5 speed close ratio 1:1 top set as seen in some B110 series cars.

Now I have nice close ratios but it's a bit slow off the line and out of very tight corners. The homologation papers and sports option list a 1:4.625 diff and I believe it was fitted to some VB10 utes sold in Japan as a "high country" version. Are there any such 37/8 crown wheels and pinions out there?

I am also allowed to change the the diff assembly to one from any source, anyone know of any options that will fit the housing?

The rules have changed an I am now allowed to change the gearbox to 5 speed so that might be an option, will the close ratio 5 speed from the B110 series cars fit a B10 body wise?

Mark

Hey there Mark,

Welcome!

I cannot speak from experience with the 5 speed conversion but the scope of work is relatively narrow (mostly involving body work rather than mechanical). I am a couple of weeks away from doing this conversion myself.

Here is what I understand is involved with the conversion:

1. Clutch arm/lever protrudes further than typical four speed, the transmission tunnel will subsequently need massaging or cutting and refitting of a small box that'll allow the gearbox to be fitted (and the clutch arm to move freely).

2. Gearbox mounting will need to be changed to accommodate the larger, longer box.

3. Clutch cable perch from a 1200 will need to be fitted.

4. The reverse light switch also fouls with the transmission tunnel. Most have cut down and filled the switch cavity, using manually operated switch to trigger reverse signal.

5. A Sunny clutch cable will need to be used, which will also need a little shimming to take up the excess slack.

The 56A 5 speed (which I think is the close ratio B110 5 Speed you speak of) is understandably the easiest to fit due to its size, I believe it clears everything. The 60 Series is quite chunky but not nearly as big as the 63 series boxes. 60 series 5 speeds appear to be the most common 5 speed around.

As for the differential, there is talk that a H150 (from a 120y - not the Borg Warner) will fit into the housing although the flange face of the diff head does not quite meet the diff housing flange face, a spacer shim will have to be applied to take up the extra gap. I'm doing this conversion in about two weeks, the same time the 5 speed goes in.

Hope that is of some help.

I have a 67 1000 2dr 3spd-CS and a 68 1000 2 door 4spd-FS.

Absolutely fantastic cars, do you have any pictures of your B10??

The H150 route wont be any help as the ratios he is after are rarer than hens teeth for the H150, I think Yahoo Japan is the best bet, if they can be found anywhere they will be there.

You're dead right there..... slight oversight on my behalf!

I can't wait to hear more about this classic rally 1000.

Must say i've not come across or heard of a shorter ratio than a 4.3 in an H 145 in Oz.
I,m more curious as to why it's slow off the mark?What size wheels and tyres are on it?

I'm using Falken RX01C tyres in 165/70 13 size. There is little choice in 13" and none in 12". At a recent event at Bagshot autocross track I found I was grabbing second gear at about 7000 when at the same spot other drivers where going for third.

I'm trying to upload photos but haven't pushed the right buttons yet on the computer.

I am interested in the 56A 5 speed and thanks, I now know I have a H145 rear end.

Mark

Attach file:

---

  C54490EA-1.jpg (68.54 KB)


  C54490EA-1.jpg (68.54 KB)

Looks like I got one photo (or set there of) to load twice so will try a shot of the motor. The battery is in the book with the big petrol tank to help weight distribution and traction.

While I am pushing my luck, the Sport Options list has a LSD. Has anyone fitted such to a H145.

Mark

Mark

Attach file:

---

  Motor compressed.JPG (79.24 KB)

is that twin 40's on a A10? good work,
the 145LDS is rare as rocking horse poo, and about $1500 in Japan second hand.
there was somebody a couple of weeks ago selling the 56 close ratio 5 speed..

The motor sits fairly high to increase ground and sump clearance (there is a sump guard as well) and the motor is tilted slightly to give more room for the caribies. They are 40s with pretty standard jetting after some unsatisfactory running. Now I have a good bottom end it will go for some dyno time soon, last time it only had 35kw at the back wheels.

It looks like I want the option 1 box like everyone else. At least with the limited power I have I shouldn't be straining it. I know how much the box is going to cost but who has one for sale, can you help with a link please to the one you refer to.

BTW I know of a B20 available in Melbourne, very standard and pretty rusty. Who is interested?

Mark

Twas me offering the 56A 5 speed, but it has been snapped up already.

Nice jigger that car!