VN Diff Shortening

[fbidek]

Attached is some details of the modification I will be making to a VN diff to suit my FB.

There is much information on this forum about this but what is often missing is the relationship between the wheel offset and the resultant track.
This will use 2 short side axles and cutting of one side of the diff housing to suit.

It shows
- FB diff and standard track with 6p offset wheels
- VN standard diff, VN track with 43p offset wheels (Commodore standard)
- VN diff shortened to suit FB track with 43p offset wheels

I will post some picture of the actual modification when the sparks start to fly and some details of some other modification including brakes etc.

Hope this will help some others contemplating simular modifications or spark some further ideas / discussions.

Ben

[DOLLER]

I'll be doing the same job shortly. Any chance of sending me those plans? They are nt coming up very good on my pc.

[fbidek]

No problem I will try and send them to you by PM.
Ben

[fbidek]

[fbidek]

A couple of ideas / tips for the job.

You should get some smaller diameter tube to reinforce the join you will make in the axle tube.
You may need to slit it down length ways to either open up or close in the diameter to fit.
With the slit make sure it on the bottom of the tube when the assembly is in the car.
This will allow for the diff oil to travel back a forth.
Drill the axel tube and rosette weld to the reinforcement tube. 4 per side, then weld the diameter of the gap, checking for alignment

A back yard way to check for alignment is with the axels removed, stand the assembly on one of the flanges.
Make sure the floor you are standing it on is level,then use a spirit level to check the other flange.
If the floor is level and then the top flange is level then the flanges are parallel and aligned.

Happy modifying.

[bat53retro]

g,day when shortening tube cut and join in center of new spring saddle .that way it acts as a brace for the join


cheers bat

[Trev]

Th only thing I don't like about this is you will have no dish on your wheels, only a small thing but I like dish .

[Blacky]

Th only thing I don't like about this is you will have no dish on your wheels, only a small thing but I like dish .

.... and the tailshaft ends up off centre

[bat53retro]

g,day i always shorten the diffs by 120 mm and put short axle on long side


cheers bat

[fbidek]

[DOLLER]

Someones been busy on the 'puter! Good work mate

[DOLLER]

Hey ben what suspension are you gunna run? Coil overs?

[Trev]

From the look of the spring hanger it will be leaf?

[fbidek]

Correct going with the original setup of leaf springs.
Coilovers would need a fairbit of work to strengthen the top coil over mounts and then some sort of triangulated 4 link.
I have done this before in my old model A hotrod, but had plenty of room and 2x4 chassis rails to work with.

I have changed slightly in the diff mods, I have decided that I will use the 26P Commodore wheels (VP IRS) so have had to shorten the diff slightly more.
I have taken info from Sammy's posts and drawn it up so it is clear in my head. End up being very close to HR width. Also shown how it will fit with 43P wheel for reference.
Pulled the diff apart and made the cuts on the weekend. Hope to fire up the welder this weekend.

[FATBOY]

In the wheel sizes you mention the P what is that in reference too
regards fatboy