I'm going 1JZ

Russell

Club Member
Are you using the same circuit board as the tacho to move the needle on the speedo?

Nope this is completely bespoke, the needle is driven by a stepper motor from GM which is controlled by a programmed Arduino.

Really simply, it detects the pulses coming in from the gearbox speed sensor wire and translates them into how many steps to move the motor to point the needle in the right direction.
If you were more local, you could take the one I have made which would help iron out the bugs in the real world. Will be a long time before mine hits the road.
 

Russell

Club Member
Isn't the speedo needle purely mechanical? or are you planning on using the guts of the tacho?

The only original guts of the speedo are the frame, which is chopped up heavily to fit the electronics in. The needle itself fits straight onto the output shaft of a stepper motor as any modern speedo does.
A stepper motor has an amount of "steps" it can move which can be controlled meaning that you can move the motor from and to any point without losing track of where it is.
By working out the degrees on the speedo face along with the amount of "steps" within the sweep you know where the min and max needle sweep is. From there you just work out how many "steps" there are to every mph and you are pretty much done.

Arduino counts the pulses from the gearbox - works out how fast its going - translates that into which "step" on the motor with the needle on the end - needle points to speed

The tacho will work in exactly the same way. I dont "need" to do it that way and can just use one of my circuits as I was going to previously.
I am only going down this route because there is another screen going into the tacho to talk to the ECU and other engine parameters so there will be an arduino in there anyway.
I can then add a needle sweep on startup, include a shift light that can vary based on oil temp or anything else I can think of.

I really like the look of the Z guages. Sitting there in their own pods like they do was one of the first things that jumped out at me years ago. I wanted to maintain that feel as well as having all of the information I need, when I need it based on the new engine.
When its done, the only thing that will stand out if you sit in the car without the ignition on will be a black space where the mileage should be. On the tacho, there will be a screen there but it will be black when off and you wont see it unless you are looking or turn the key.
 

johnymd

Club Member
Ah OK. So with my speedo I could just use another tacho with your circuit board and adjust it to suit the number of pulses? or am I missing something?
 

Russell

Club Member
Ah OK. So with my speedo I could just use another tacho with your circuit board and adjust it to suit the number of pulses? or am I missing something?

Nope, the entire mechanism gets replaced.

Might be able to do it that way but I can’t see it being accurate.
You also wouldn’t have any mileage or anything.


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Russell

Club Member
Been offline for a while as I bought my first house. In addition the workshop I had been using closed down.

With all of this going on it was touch and go as to whether I would be able to even keep the car.

Getting rid of it was always an absolute last resort after I had sold all of my children for spare parts so thankfully I’m keeping it. Just pushing its completion out even further.

We decided that before the workshop closed we should get the underside sorted. Couple of small holes but mainly the chassis rails were pretty ruined.

So that’s what we did and here’s the end result.
b96efeb95b9b0644bd5e4c959dafcb86.jpg


The underside of the car is now solid and we can technically make progress with the car on the floor.

That lead me to working out what to do with it when the workshop shit it’s doors.
Our new house has a garage built in and my wife categorically told me that she needed the garage for storage and a utility area so wouldn’t be allowed a car in it.

I bought some of those skates you can put the car on and now my wife isn’t talking to me.
7180c04c531d1fb0e35ac2b0228dda04.jpg


Here it will languish until we can find a local unit to rent for sensible money as a hobby workshop and get back to it.

Unfortunately all the parts are stacked in and around it which means I am unlikely to work on it at home. By the time I drag it out and move everything to get to the area I’m working on I will be out of time and have to put it all back.

It’s a shame to be slowed down even more but I’m really happy that I didn’t have to get rid of it!


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jonbills

Membership Secretary
Site Administrator
Glad you've still got the car. Did you have to sell the kids for spare parts in the end?
 

AliK

Vehicle Dating Officer
Staff member
Club Member
REALLY please for you buddy - glad you kept the car and that garage is nice and large looking!!

Completion time being pushed back is irrelevant - it just makes the end goal so much sweeter. Just ask Franky! [emoji1787]
 

Russell

Club Member
Glad you've still got the car. Did you have to sell the kids for spare parts in the end?

Unfortunately no one would take them so still stuck with them. If anyone needs any spares, let me know. Few sets of decent kidneys etc.


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Russell

Club Member
REALLY please for you buddy - glad you kept the car and that garage is nice and large looking!!

Completion time being pushed back is irrelevant - it just makes the end goal so much sweeter. Just ask Franky! [emoji1787]

Cheers Ali, will get it back on track. Just want to drive it again!!


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Woody928

Events Officer
Staff member
Club Member
Great to hear that you're still keeping this going dude, from what Iain said I had faith that something would come through (Massive shame for him though). Sounds as though the house move has been keeping you really busy....

Chassis rails now look fantastic, it'll get there eventually and when it does it will be awesome knowing you two!
 

Russell

Club Member
Working from home for lockdown means I have a couple of hours in the day to play cars!

First job was to actually find it in the garage though having been buried for almost exactly a year!

Success!
635e388858aa849f89063e3bbbdd2508.jpg


Been a while since I have seen this!
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Cracked on with the brake servo and master cylinder I got from an R33 Skyline many moons ago with the help of my 3D printed template so the holes are all in the right place.
3c07cd9ea69315c71f3263ebf7605b60.jpg


Unfortunately my trusty engineering friend is also locked down so can’t make huge progress!


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AliK

Vehicle Dating Officer
Staff member
Club Member
Yayyy!!! You’re still on the planet! Wondered what had happened to you chap! Welcome back to the Z world - following with great interest.
 
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