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speedo error with datsun gearbox

 
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morrisman1
I can steer now


Joined: 12 Jul 2007
Posts: 201
Location: Invercargill, New Zealand

PostPosted: Tue Sep 09, 2008 8:41 pm    Post subject: speedo error with datsun gearbox Reply with quote

hi

my ute has the combination of 175/70r13 tyres, a 3.9:1 toyota diff, datsun 4 speed gearbox and morry speedo. does anyone know what sort of speedo error i would get with this combination? im sure that someone here has a morry with a datsun gearbox and morry speedo!

cheers,
Cameron


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John Ballard
valued contributor


Joined: 11 Feb 2004
Posts: 2646
Location: Dubbo NSW

PostPosted: Tue Sep 09, 2008 9:04 pm    Post subject: Reply with quote

You have that many variations there, who knows how your speedo is reading.
However it is easy to have properly calibrated at any instrument repairer.
They need this info.
1. Mark out 20 meters park car front wheel centre of mark drive slowly to next mark at 20 meters .
2. Count very accurately no of turns of end of speedo cable about 13-17
3. Take speedo and calculations in to be recalibrated about $60 AUD.,
The cable has a square end I marked mine with white paint and watched it turn as I drove.


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morrisman1
I can steer now


Joined: 12 Jul 2007
Posts: 201
Location: Invercargill, New Zealand

PostPosted: Tue Sep 09, 2008 9:15 pm    Post subject: Reply with quote

when they calibrate the speedo, does it correct the odometer aswell? im trying to find out whether there are replacement gears available for the datsun gearbox to correct the cable ratio if possible. i guess ill get it on the road in the mean time but it will have to be pretty accurate to get through certification.


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Triumph Man
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Joined: 13 Sep 2003
Posts: 1890

PostPosted: Wed Sep 10, 2008 9:31 am    Post subject: Re: speedo error with datsun gearbox Reply with quote

morrisman1 wrote:
hi

my ute has the combination of 175/70r13 tyres, a 3.9:1 toyota diff, datsun 4 speed gearbox and morry speedo. does anyone know what sort of speedo error i would get with this combination? im sure that someone here has a morry with a datsun gearbox and morry speedo!

cheers,
Cameron


More than ussual Very Happy Very Happy Very Happy
Trev
Aus


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Triumph Man
valued contributor


Joined: 13 Sep 2003
Posts: 1890

PostPosted: Wed Sep 10, 2008 9:41 am    Post subject: Reply with quote

morrisman1 wrote:
when they calibrate the speedo, does it correct the odometer aswell? im trying to find out whether there are replacement gears available for the datsun gearbox to correct the cable ratio if possible. i guess ill get it on the road in the mean time but it will have to be pretty accurate to get through certification.


You have to have both the speedo & odometer calibrated.
Mate there are heaps of different speedo's, look at the number just above the smiths on the face, eg 1000, (thats not engine size) & to many variables as John said, thats why we cant give you a reading.

Mate they dont check the speedo here for rego as long as it's reading something Very Happy

You can get the speedo done or get a ratio box made that bolts to the gearbox (or just follow someone & remember how far out it is Very Happy )
If your thinking of changing to a 5 speed later or getting different wheels the ratio box is the way to go, as once you have it it is only a matter of changing the small plastic gears to true it up again.
Trev
Aus


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Auspest
I've got trainer wheels


Joined: 19 Jan 2008
Posts: 15
Location: Brisbane

PostPosted: Sun Sep 14, 2008 8:29 pm    Post subject: Reply with quote

Had the speedo repaired in my sprite a number of months ago, I have Datsun running gear in it. You can get the ODO calibrated as wel but my guy said they are running out of gear parts so sometimes can only get close.
Also got little red dots put at every 20km/hr mark so makes it easy to read in kms
Ratio box may be the way to go for futyre changes


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tortron
Got the hang of this ...


Joined: 02 Mar 2008
Posts: 280
Location: New Zealand

PostPosted: Sun Sep 14, 2008 9:10 pm    Post subject: Reply with quote

what about getting a custom face printed up?
can get them in vinyl printed plastic (wont fade) and translucent (for back lighting) for around $40 i think it was (was for an a4 size i think, so could get a bunch made)

if you are interested look it up on the nzhonda forum (i was tricked into going there i swear Embarassed )


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morrisman1
I can steer now


Joined: 12 Jul 2007
Posts: 201
Location: Invercargill, New Zealand

PostPosted: Sun Sep 14, 2008 9:16 pm    Post subject: Reply with quote

ive got a mate in the signwriting business so he could possibly make something up for me. the odometer would still be out though


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Boeing Bob
Got the hang of this ...


Joined: 08 Jul 2007
Posts: 284
Location: SYDNEY, AUSTRALIA

PostPosted: Sun Sep 14, 2008 10:50 pm    Post subject: Reply with quote

Yellow Van Like the old story about the bumble bee. Aorodynamically, it is impossible for a bumble to fly, but as he knows nothing about aerodynamics, so he goes ahead and does it anyway. A similar thing can be said about speedos. My van has a Sprite diff and 13" wheels. I took the van to my local instrument man, he removed the speedo, connected a "revolutions counter" and we drove around his measured 1 Kilometer track. At the end, he did some quick calculations and said " I need a gear wth X number of teeth to which I said, "where will you get that?" "Simple", sez he, "I'll make one". There's nothing wrong with my speedo.

I also had a similar problem a few years ago with the depth sounder on my boat when an el cheapo plastic gear sheared. I took it to a gear cutter and he made me up a nice new brass one. Once again, no problem. As the good book sez, "seek and ye shall find".

Many of these guys also have the facilities to make up completely new face plates if required or simply make alterations to your old ones.



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