Can a round p6 v8 speedo be converted to electric?

ratwing

ratwing

Active Member
I've replaced my 4 speed box with an LT77 but can't connect a drive cable to it - it's in my trike and the battery is right next to the speedo drive on the gearbox so no room for it.
I was wondering if there is anything electrical available that goes on the back of the original speedo and is driven by a sender fitted in the gearbox speedo drive?
I've seen replacement speedos of this type but would prefer to keep the original if possible.
 
Yes, people are doing this to fit the ZF 4 speed automatic box. The option most people (inc. myself) have taken is the Dakota Digital ECD-100. You'll need a custom cable to fit which can be made for £30-40.

Can you simply relocate the battery. The above ain't cheap.... In fact if not you'd be better off fitting an electric speedo.
 
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Another vote here for the Dakota Digital box - I've fitted one in mine, not cheap, but very very good. If it's a complete custom job, which it sounds like, fitting an alternative, electric, speedo is going to be an easier and cheaper option.
 
Dakota Digital ECD-100 : this looks like what I want but isn't it expensive!
Unfortunately there isn't anywhere else to put the battery so I'll probably have to change to an electronic speedo. Hopefully I can find one with an analogue display that either looks similar or that I can take apart and re-paint so it doesn't look 'modern' if you see what mean.
 
I know someone that had the SD1 electronic transducer fitted to his LT77, and the SD1 electronic speedo head to match it fitted into the P6B instrument cluster, so that's similar looking.
 
I have an idea - the diff is bolted to the chassis and there is enough 'slack' in the propshaft sliding joint to fit a toothed belt pulley between the flanges so maybe I can drive the original cable from another pulley by belt? Whether I can fit the second pulley depends on the speedo drive ratio (whatever that is) but there might be room beside the diff. The propshaft is short, a little over 8" long so I might even be able to extend the driven pulley shaft so I don't need to get a non-standard length cable made? Time to go and do some measuring...
 
I wonder if you could take a Landrover Td5 speedo head, fit the p6 gauge face to it and get it recalibrated to match the new face? There is a thread on Lr4x4.com where a few guys managed to reverse engineer the heads and can now make them read pretty much anything you like over any given scale. One forumeer who did a lot of the figuring out was called "CwazyWabbit" I think, which might help you in a google search.
 
Well, a bit of checking shows its quite possible to make a belt drive off the propshaft and I can fine tune the speedo reading with an in-cable tachograph gearbox but cost wise it isn't worth doing. Also, it'll be a pretty big job to replace the belt if need be.
A Dakota Digital box & sender is going to be around £375 from the USA, I haven't had a reply from their UK supplier but reckon it'll be similar.
I've found this, it's slightly smaller at 86.5mm across the bezel but I'd make up a different one anyway and repaint the insides. Not sure about the big digital bit at the bottom (yuk), I'd have to leave some of it showing for the odometer but it's only £140 delivered including a sender.
koso-crb01s-speedometer-with-warning-lights.-1975-p[ekm]370x347[ekm].jpg

Also found this, £220 including a sender and is the right diameter at 90mm. I'd probably open it up to alter the face but is it worth spending an extra £80 just to not have the big digital bit? Decisions, decisions...
smiths-black-dial-waterproof-mph-speedometer-489-p[ekm]370x370[ekm].jpg
 
ratwing said:
Well, a bit of checking shows its quite possible to make a belt drive off the propshaft and I can fine tune the speedo reading with an in-cable tachograph gearbox but cost wise it isn't worth doing. Also, it'll be a pretty big job to replace the belt if need be.
A Dakota Digital box & sender is going to be around £375 from the USA, I haven't had a reply from their UK supplier but reckon it'll be similar.
I've found this, it's slightly smaller at 86.5mm across the bezel but I'd make up a different one anyway and repaint the insides. Not sure about the big digital bit at the bottom (yuk), I'd have to leave some of it showing for the odometer but it's only £140 delivered including a sender.
koso-crb01s-speedometer-with-warning-lights.-1975-p[ekm]370x347[ekm].jpg

Also found this, £220 including a sender and is the right diameter at 90mm. I'd probably open it up to alter the face but is it worth spending an extra £80 just to not have the big digital bit? Decisions, decisions...
smiths-black-dial-waterproof-mph-speedometer-489-p[ekm]370x370[ekm].jpg
Click to expand...
Depends on how skint you are and will the digital one really p!!! You off every time you look at it!
 
Unfortunately there isn't room for a cable or 90° drive between the battery & gearbox, this is the only pic I have handy but you can see how tight everything fits in. (taken while building, hence the loose wires, wonky battery strap etc )
DSC01676_zpsut6txvur.jpg
 
There are some great looking GPS speedos available now, for very reasonable money.
I decided it was comparable if not cheaper to buy a whole new gauge set for my build with gps speedo. Veethree make the set I bought which look really good in the flesh, they are black sterling series. Speedhut, autometer etc all do different sized gps speedo options, plus plenty of lesser known and cheaper options on Amazon etc.
Best part is no calibrating if you ever change ratios or wheel size etc!
Jim
 
Someone needs to invent a GPS speedo that is effectively a blank canvas of a screen.

The idea being (in my mind), you can take a photo, or scan the face of your original speedo, load it onto your gps speedo, calibrate it to hit the right indicated numbers at the right speeds and have a digital copy of the original analog speedo.
 
I'm pretty certain a stepper motor with the correct controller will be able to do what you want. Someone who is good with electronics will be able to sort out the workings of it. The pick-up end becomes a DC generator and the controller will sense the voltage and convert it to the stepper to position the needle.
 
Have you thought about making a belt drive off the output flange? you could use a robotics type belt and could position it wherever you want?
 
unstable load said:
I'm pretty certain a stepper motor with the correct controller will be able to do what you want. Someone who is good with electronics will be able to sort out the workings of it. The pick-up end becomes a DC generator and the controller will sense the voltage and convert it to the stepper to position the needle.
Click to expand...


That's exactly what the Dakota digital is. A company called "Monarch Stags" do something similar for their ZF conversion. I tried talking with them about this solution (which should fit directly on the P6 speedo drive) but they didn't seem interested.
 
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