Right firstly get hold of a spare 300 and Early 400 Speedo (Similar needle to 300 type)

Like this


Next thing to do is strip the speedos down. Firstly remove the rest pin for the Needle. Dont worry about position it is marked on the gauge face.
To remove pin, use a small pair of pliers and pull the pin out straight. otherwise you will bend it. Next thing to remove is the Needle itself. I found the best thing to remove this safely is a fork!!!

Like so.


You can now remove the trip push thingy. Hold the acrylic and pull the front section off. Next look at the back where it sits on a small bar. Twist the square block then you can remove it



Right you should now have this in front of you.

Stripped 300 speedo


And Stripped 400 Speedo


Right here is the comparison of the speedo mechanicals!!!
300 on Right 400 on left
Sorry about this pic they dont show up too well on white paper!!


From the front note 1/10 mile in yellow on 300!!!


Now for the reassembly!!!
You will need these components!! The 400 speedo mech, needle, face. And the 300 acrylic backing, screws and trip push pieces.


Assembly is simply reversal of unassembly.
When you come to put the needle on line it up with mark on the face of the gauge like this....


Make sure you fit this first then the pin!!! The new hole for the pin will need to be redrilled i think it is 1.5mm or 2mm i cant remember. Check that with the existing hole!!
Next job is to fit the trip push!!! push through hole onto bar and twist square block. Push front piece on!!

You should now have something that looks like this!!!!


The next job is to trim the face of the dial, to do this fit the speedo in the cluster and simply trim with scissors!!!

If you want to be able to see the nothches all the way round the speedo you will need to remove the small recess from the speedo housing!!! if not it will all bolt together as it is!!!!

Well i hope you guys put this to good use!!!
Just remember who did it first!!!!!
Cheers Adam

Excellent guide Adam, something which I'm, quite tempted to do now, as you've proved it's possible and quite siple too, once you know the required parts and how, but I may add a slight twist to mine to make it different, we'll see if I ever get time!
Pete

I would probably do it in a flash if someone could print up a 300-sized 140mph face.

Awesome work Adam, very impressive.

cheers

James

I've made that change to... Started some weeks ago and finished today

Foto:



Video:

http://nitrate.website.online.pt/temp/Video000.3gp

Tomorrow I'll add a foto taken with the digital camera

Nice loking.

Some good quality fotos

fantastic write up adam!

cheers mate!

Shimon

Adam, thanks for the great idea:) I tried it last sunday, everything went very smooth. Just a few questions:

-how do I best remove the small recess?

-before this mod, when I was running around 3300 rpm, the speedo would would indicate 120km/h, but after modding it says I'm driving about 135km/h! Any idea of what might've gone wrong? Normally the trip from my house to my parents' is 70 km, yesterday it suddenly was 65!

Best way is cut small amounts from the back with a stanley knife/blade.
When i did my mod to check the calibration in my car i used the driving comp i have installed which was calibrated to original speedo. And with out changing it it was spot on, which indicated original speedo reads high!!!
Cheers Adam

In that case it's really strange that it doesn't work with mine... might it have something to do with accidently hitting or bending the 'spiral' to which the needle is connected? Or doesn't that affect the daytrip counter?

tia

Debatable really as my trip is slightly out, like 2miles after counting one hundred and something so i'm not sure!!! Best way would be to laser test the speed of the car compaired to what it actually saying its doing
Cheers Adam

in mine I noticed that after the transformation it has an error of 50 meters every 1km.

I would imagine the most likely thing is that the mechanism released some tension when you removed the needle. I've definitely seen Haynes speedo sections mentioning taping the spindle in place before moving the needle, as the mechanism is 'pre-loaded' to give the correct reading.

Any news on the cruise control take-off Adam?

cheers

James

No not yet mate been too busy with the brakes!!
Hard trying to do electrical stuff as they take so much working out!!
I need to mount the standard 440 stalks first and find a doner 400 with CC first!! lol
Cheers Adam

I've picked myself up one of these 4 series spedo's. All I need to do is get it fitted. Other projects slowing it down.