67-72 Electric speedo

[dayj1]

Originally Posted by DM72C20

Just checking in if anyone has this swap working with a Gen IV engine? I've got an 09 4.8 going into my 72 C20 and was contemplating this gauge swap, but saw that it might not work. Thanks from social distancing in Toronto.

If your setup uses an e38 ECM, VSS out is pin 57 on connector 1. By default, it’ll be 128k PPM (originally went to the antilock brake controller), but it can be changed to 4K PPM in the tune. The 4k signal will work fine with the S10 speedometer.

[DM72C20]

Thanks for the info dayj1!

ls1nova71 - are the kits still available? I sent you a PM but haven't heard back. Thanks.

[prodjay10]

How can you get the mileage to match current speedo?
Posted via Mobile Device

[plumber452]

I'd be interested if lens kits are still available.

Thanks

[plumber452]

I am currently working on the wiring for my speedo swap and it appears in the photos that a relay is used in conjunction with the volt meter. Is that required?

As to Prodjays question about the odometer I just reset mine yesterday. It's a little tediuos but it's not that diffucult.

[ls1nova71]

Originally Posted by plumber452

I am currently working on the wiring for my speedo swap and it appears in the photos that a relay is used in conjunction with the volt meter. Is that required?
.

No relay is required for the voltmeter. That relay in the pic was part of an automatic headlight set up that truck had.

Originally Posted by prodjay10

How can you get the mileage to match current speedo?
Posted via Mobile Device

I don't really know how to explain it, but you just kind of have to mess with it a bit. Once you take it out and play with it, i think you'll see how its done.

[Factory Guy]

Thanks to Ls1Nova71 I have started on my Squarebody swap to digital, even though I don't need it yet. Look at how close the S10-Speedo lines up with the Squarebody speedo bezel. Looks like the only thing I will have to modify is the odometer hole as it is a tad too small for the Odometer out of the S10.

The screw holes to mount the digital speedo even line up!

[ls1nova71]

Originally Posted by Factory Guy

Thanks to Ls1Nova71 I have started on my Squarebody swap to digital, even though I don't need it yet. Look at how close the S10-Speedo lines up with the Squarebody speedo bezel. Looks like the only thing I will have to modify is the odometer hole as it is a tad too small for the Odometer out of the S10.

The screw holes to mount the digital speedo even line up!

You should be able to move the numbers for the odometer over by sliding them on the shaft they're mounted on. Just have to be sure the gear on the end still makes contact with the drive motor. If it doesn't, you can add another gear to it.

[lutronjim]

Would the scale/ratio be correct?

[plumber452]

Not to step on lutronjim's question but I need help. I just completed my conversion and was able to bench test my dash lights, volt meter , etc. I couldn't bench test the speedo. So, today I layed my new cluster in the seat hooked 12 volt ignition, a ground and the wire coming from the PCM to the speedo and took it out. Nothing. The needle didn't move at all. I then disconnected everything and hooked my meter to the wire from the PCM and test drove it. At idle 0 volts. As I drove the voltage increased to a max of 6.6 volts at appx. 35 m.p.h. Any thoughts? Thanks

[ls1nova71]

Originally Posted by lutronjim

Would the scale/ratio be correct?

Probably not, that's why i had to redo the face. 60mph needs to be straight up.

Originally Posted by plumber452

Not to step on lutronjim's question but I need help. I just completed my conversion and was able to bench test my dash lights, volt meter , etc. I couldn't bench test the speedo. So, today I layed my new cluster in the seat hooked 12 volt ignition, a ground and the wire coming from the PCM to the speedo and took it out. Nothing. The needle didn't move at all. I then disconnected everything and hooked my meter to the wire from the PCM and test drove it. At idle 0 volts. As I drove the voltage increased to a max of 6.6 volts at appx. 35 m.p.h. Any thoughts? Thanks

So all the other gauges work? Did the odometer work at all? If it did, then the stepper motor for the speedo needle could be bad, or if you painted it, it could be stuck to the stopper the needle rests on when the ignition is off. Did you put the needle on with the ignition powered up so you know the needle is resting at 0mph?

[plumber452]

Thanks for the suggestions.
1. I did not drive it far enough or even think to look at the odometer
2. I did paint the needle but it was off for at least a couple of weeks before I reinstalled it.
3. I did not install the needle with it powered up but when I received the S-10 cluster from E-Bay the needle wasn't at zero so I powered it up and it went to zero. Before I insalled the C-10 needle I powered it up and watched to see if I could see the shaft turn. I didn't see any movement so assumed it was zeroed, if that's a word, out.

So, I'll check all of these things out and get back. Perhaps when I powered it up and didn't think I saw movement of the shaft it is so slight that I couldn't see it move and then when I disconnected power it went back.

Again,

Thanks

[ls1nova71]

It's absolutely imperative that you install the needle with the speedometer powered up. You likely won't see the shaft of the motor move since it's small and the movement isn't a lot at times. Even if it was at zero powered off, just the act of installing the needle could move it enough for the needle to be off by a bit. Also, when installing it powered up, there's a chance you won't get it right on the first try, so it takes some trial and error to get it perfect.

As for painting the needle, for some reason it doesn't always matter how dry the paint is, it can still stick to the little needle stop if there's paint on the needle at that spot, because the stepper motors don't have enough power to overcome it even it is only slightly stuck. What I do is carefully take a razor blade and scrape the paint off the needle at that spot so it can't stick to it.

[plumber452]

Update time. After implementing your suggestions I have made a little progress, I think.

1. Both the regular odometer and trip odometer are working

2. The needle will move up to about 5 mph and that's as far as it goes

3. After coming to a stop the needle will not return to zero.

4. With the truck idling, in park, if I remove the needle, reinstall the needle at zero it does the same thing. Moves up to about 5 mph stops and doesn't return to zero.

Anymore ideas?

Thanks

[ls1nova71]

Is the needle hitting anything? Even something small can stop the needle. Make sure the needle goes through its full sweep without touching anything.

[plumber452]

Success!!!!!!

You were spot on. The new speedo overlay was covering up part of the hole where the needle goes thru and the needle was ever so slightly rubbing the "Shaft" of the needle. I used my Xacto knife, trimmed it back , powered the cluster up, reinstalled the needle and took it out for a test drive. It swept up smoothly and returned to rest just shy of the stop.

Now if I can install the cluster in the tub and bezel without screwing it up I'll be happy!!!!LOL

Again, THANKS !!!!

You are the MAN.....

[ls1nova71]

Cool! Glad you got it working.

[Low Elco]

Originally Posted by Factory Guy

Thanks to Ls1Nova71 I have started on my Squarebody swap to digital, even though I don't need it yet. Look at how close the S10-Speedo lines up with the Squarebody speedo bezel. Looks like the only thing I will have to modify is the odometer hole as it is a tad too small for the Odometer out of the S10.

The screw holes to mount the digital speedo even line up!

As a new '78 Squarebody owner, I am very interested in knowing everything that's going on here. Please let me know.

[plumber452]

Well I thought some people might be interested in a update. I have completed my electric con version and it works great!!!! My biggest disappointment is in the way I painted the numbers on the face. LS1Nova71 was very clear about painting the numbers and doing light coats. I did light coats but using the "If a little is good a lot is better" mentality, the heavy coats resulted in some paint bleeding under the stencil on a few numbers and they didn't come out as crisp and sharp as LS1 Nova71's.

Also, on the temperature gauge I ended up adding in I think 7ohms of resistance to get the needle to read in the normal range at normal operating temperature.

So, all in all I really enjoyed working on it, it works great (and accurately) and love it when a few people that has seen it says "I didn't know these trucks had a 120MPH speedometer" LOL!!!

Again thanks to LS1Nova71 for all of his help and I'd do another one if I get the chance.

[prodjay10]

I want a speedo decal.

[ls1nova71]

Originally Posted by plumber452

Well I thought some people might be interested in a update. I have completed my electric con version and it works great!!!! My biggest disappointment is in the way I painted the numbers on the face. LS1Nova71 was very clear about painting the numbers and doing light coats. I did light coats but using the "If a little is good a lot is better" mentality, the heavy coats resulted in some paint bleeding under the stencil on a few numbers and they didn't come out as crisp and sharp as LS1 Nova71's.

Also, on the temperature gauge I ended up adding in I think 7ohms of resistance to get the needle to read in the normal range at normal operating temperature.

So, all in all I really enjoyed working on it, it works great (and accurately) and love it when a few people that has seen it says "I didn't know these trucks had a 120MPH speedometer" LOL!!!

Again thanks to LS1Nova71 for all of his help and I'd do another one if I get the chance.

Thanks for the update and kind words. Glad you got it done and working.

Originally Posted by prodjay10

I want a speedo decal.

PM sent

[anew4961]

do you have any more kits if so i would like 3 of them Thanks

[1965Impala]

Hello, Eric (and others who have contributed to this thread). It is getting close to 10 years since Eric started this and guys are still doing this conversion! What a great thread!

Eric, if the face and stencil stickers kits are still available, I would like to have 3 of them. Pleas let me know. Thanks.

[ls1nova71]

Originally Posted by 1965Impala

Hello, Eric (and others who have contributed to this thread). It is getting close to 10 years since Eric started this and guys are still doing this conversion! What a great thread!

Eric, if the face and stencil stickers kits are still available, I would like to have 3 of them. Pleas let me know. Thanks.

Wow, kind of hard to wrap my head around the fact that this thread is almost 10 years old! Geez, time flies!

I sent you a PM

[ddp]

Hi Eric,

I would be interested in buying 2 of your overlay, stencil, and template kits if you have any available.

I just checked and it was 2013 when I bought one of your cruise control / turn signal levers for my '71. With that part and your "LS factory cruise control hook up" posts, I've had "factory" retrofitted cruise working in my truck since. Probably one of the best upgrades i ever made to it.

Thanks,
Don