speedos arggggggg!!!!!

[ben]

hey folks listen to this..

my original van i was doing 125 on the speedo to 100 real kms..

swaped all the running gear into black beddy but different speedo.. 110 on speedo to 100 real kms..

just last week i changed transmission to trimatic auto (much better than m21) 80 on speedo to 100 real kms..

What is going on???

i have not changed the speedo gear at all in any of these swaps and none are consitant!!!!


so would i be right in saying you can alter the speedo ratio by

1. adjusting the speedo (ive herd people say there is an adjuster on the back so that makes sense)

2. adjust the speedo gear (the obvious one)

3. change the gear inside to transmisson to change ratio too.. (never herd of this)


thanks for the help

cheers
ben

[Worzel]

The transmision has a coloured plastic cog drivinng the speedo cable,
there are different colours avaliable for different ratios,

the easiest is to try a few and you may find one that is perfect.

There is an adjuster on the back of the speedo but don't go there unless you've tried everything else

[ben]

hey worzel,

i thought that was the only way to change the gearing??? with maybe the knob on the beack of the speedo..

but obviously the transmission has something to do with it also.. because when i changed transmissions while using the same speedo gear and same speedo my speedo was flippen 30km different to the other transmission!!!!

with the old transmission the closest i could get it was 10kms out and that was with the 2.8 cog???

so i dunno.. ive had no luck. but i think i might go to the wreckers and buy all the different color speedo gears.. then find a speed board somewhere.. drive and change gear drive and chage gear until i find the closest one.. then maybe try the tuner on the back of the speedo..

if i cant use the tuner onthe back of the speedo ill never get it right cause the speedo cogs im using were for the holden diffs, 2.8, 3.08, 3.55, 4.1



my diff is a 3.23 smack bang in the middle of 3.08 and 3.55 so i may never get it accurate unless i get a reducer box or something.. far out!!! man i sick of almost loosing my licence cause the damn speedo is wrong!! could have paid for someone to fix it by now..



ben

[Worzel]

Ben, to use the lever on the back of the speedo you need to take the speedo out of the dash, and drive around with it on your lap
(maybe you cab figure some way of clanping it to the dash (what dash?))
Then either drive around looking for a speed indicator thingie or arrange with a freind in a later model car to drive at an agreed speed until you flash him and then change to another speed to see if it still is accurate.
I wouldn't do it over the mobile as your hands will already be full

Clear?

[ben]

yeh ok.. do you know how much adjustment you can get out of the one on the back of the speedo? like it is 10's of kms or only like 5 kms??

cheers
ben

[Marishka]

worzel,s right on the money, the speedo has a small lever inbetween the speedo body and faceplate, im not sure how much adjustment there is but will check it out, i got a spare ready to do the check with,
wish i had 4 arms though. lol 

[snow]

Yea i've done this by changing the colour cogs in the tranmission, when i brought the beddy and driving home the speedo needle just was jumping all the time was a busted cable got a new one made but the person before me must of put a different trimatic in and never worried about the speedo, i would luv to tell you what colour cog to use but i have a different diff ratio to you was just trail and error, have a look at the old holden site they have a section on this, ibrought my cog just from a mech but if you do some think there the same price as gold, the colours i was after were gone at the wreckers

cheers snow

[Bren]

rare spares bought alot of coventrys old stock of speedo gears, but i think they charge a heap for them. covs also used to have a book with a chart that let you work out the colour gear needed. if you ring them now you have to fluke the right person who knows what you are talking about. most of the newer staff dont know how to look it up.

[Tweaker]

Yeah Bren is right about ringing Rare Spares. You'll need to give them your tyre size, diff ratio and box type for them to match the colour. Everytime you change one of these you need to cjange the gear on the end of the speedo cable.

If you go for the 'follow another car trip' you're better off driving a set distance as apposed to a set speed as this is more accurate! Have you friend zero their trip meter (take a note of yours) and have them drive say 10k's (the longer the distance the more accurate) and then compare your distance to your freinds. Easy peasy and it can be done anywhere. Matching up a gear or having a conversion box made up should then be straight forward!

Good luck! 

Let us know how you go!

[ben]

sounds like a good method tweaker.. only trouble is my odometer doesnt work lol.. i do have tons of spares.. but ofcourse as soon as i change the speedo the neddle will read differently!!! and im used to nows settings ay.. flippen heck!