Changing Speedo/Clock to Speedo/Tacho

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Joined
Apr 19, 2017
Messages
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Location
Melbourne, AUSTRALIA
My Car
I have just acquired a 1971 Mach 1 and setting out on a restomod to make this vehicle something different and special.
This forum is my choice as 71-73 models are not popular in Australia and information is difficult to find.
My VIN: 1F05M218422
It will be along the lines of one in Japan.
(http://www.speedhunters.com/author/2281434115/)
Hi Guys ,

I have managed to find a Speedo/Tacho combination to replace my

existing Speedo/Clock set up.

The cost is approximately US$200 and it is here in Melbourne, Australia.

The printed instrument circuit is damaged and needs replacement.

Would anyone know the correct one to replace it, I have a 1971 Mach 1

351 V8 - ID: 1F05M218422.

A part number or a source would assist thank you.

Best Wishes to everyone for Christmas & the New Year.

Melfunctions

 
only references I have are vague, start with

D1ZZ10K843B

and

D1ZZ10K843C

they are listed as printed circuits for the instrument panel but I don't have anything to specify clock or tach at the moment. I may be able to give you the late 71 with tach number from my car with tach (built late 71) but sold as 72 it will take a few days. Before you go to all the trouble though do you have the trip meter/tach lens as they seem to be unicorns that don't even have a value.

 
Hi Mel, try this one - https://www.cjponyparts.com/instrument-cluster-circuit-board-with-tachometer-1971-1973/p/DCB4/

I bought the non-tach type and getting RCC to convert my clock to tach - great bloke to deal with
Hi Oz,

Is that 'Rocketman' you refer to?

Would you mind giving me some more details.

She is all apart now with guards and doors off being

media blasted and coated.

I am trying to build my stock of parts for the interior and dash,

Don from Ohio Mustang is assisting me - have you converted to RH Drive

or not?

Thanks for your help - send me you mobile number so we can talk more.

Merry Christmas.

Melfunctions

 
only references I have are vague, start with

D1ZZ10K843B

and

D1ZZ10K843C

they are listed as printed circuits for the instrument panel but I don't have anything to specify clock or tach at the moment. I may be able to give you the late 71 with tach number from my car with tach (built late 71) but sold as 72 it will take a few days. Before you go to all the trouble though do you have the trip meter/tach  lens as they seem to be unicorns that don't even have a value.
Libram,

Thanks for your reply.

I am not sure what you mean by lens - the unit is complete with

the flat lens covering both Speedo & Tach.

Would you mind explaining for me as I am new to this car rebuilding caper!

I see I can perhaps buy a complete unit from Rocketman which is possibly

the best way to go as I know it will work.

I have a head up display in my daily driver (E46M3) and I plan to install one in

the beast but I still want working gauges.

Thanks for your interest and help.

Merry Christmas,

Melfunctions

 
my speedo tach, and as far as I know all others that are factory have a trip meter. The push button for the trip meter is actually a formed component in a different instrument lens. If you're putting in a factory instrument cluster that was speedo tach it will have a trip meter. You can put the standard lens over it but you'll be staring at an odometer that constantly ticks to 999....maybe 9999 all the time. If you're using an aftermarket cluster that might be different. But at the moment I'm sitting on a factory speedo tach with the trip meter and trying my best to either refinish the original lens and make it look good with the reset button or I'll have to cut out the button and retrofit it into a blank lens ( I have doubts that I can hide it completely because of the design).

 
also out of curiosity, how do you plan to put a HUD in an old mustang? My g dad would kill to add a HUD to his caddy but I've never seen anything that I could add for a HUD.

 
my speedo tach, and as far as I know all others that are factory have a trip meter. The push button for the trip meter is actually a formed component in a different instrument lens. If you're putting in a factory instrument cluster that was speedo tach it will have a trip meter. You can put the standard lens over it but you'll be staring at an odometer that constantly ticks to 999....maybe 9999 all the time. If you're using an aftermarket cluster that might be different. But at the moment I'm sitting on a factory speedo tach with the trip meter and trying my best to either refinish the original lens and make it look good with the reset button or I'll have to cut out the button and retrofit it into a blank lens ( I have doubts that I can hide it completely because of the design).
Libram,

In Australia we have one called 'Polaris' I am sure there may be similar ones  there.

They are powered by cigarette lighter (Hate leads showing) but I have mine in the M3 direct wired,

operates on GPS signal and you mount the unit where it is comfortable to read.

We have an enormous number of speed detection points in Melbourne and 3klms

an hour over say 60 kph will cost you $300 plus demerit points.

My unit is programmed to detect the fixed traffic intersection cameras - quite often

people speed up to catch the lights - these cameras detect your speed through the intersection.

Our Government is hooked on the revenue and keep finding new applications to detect

anyone who speeds!

I find it difficult to drive other cars as I am so used to this fantastic device - cost was about $150

Aus dollars.

The only problem is the GPS signal is difficult to pick up in forests or heavily treed areas but that is

the only negative.

Now I know what you mean regarding trip meter ect.

Thanks for your interest and support.

Melfunctions

 
Hi Melfunctions, I'm not an expert on this, but I do know that a factory tach is positive feed, not negative as most others are. My car is a non-tach, but with idiot lights. I purchased a tach conversion from Rocketman, yes RCCinnovations.com as it is a negative tach and plugs right into the existing circuit board with a simple wire hook-up. I could be wrong, but I think you'll find you need a different wiring harness under dash to run a factory tach. I'm sure more knowledgeable member will add to or correct me on this. I actually sold a factory speedo-tach rather than piss around with all that extra work. My tach combo looks great and at a glance, no-one would even know it was not the factory tach.

Geoff.

 
Stanglover is correct. I went through all of the problems as my 71 mach was a non tach model. the original owner bought a factory tach and replaced the clock but the wiring harness plug would not match up with the circuit board and have the tach work properly. Had to go back to the clock and when money becomes available will go the Rocketman tach route. Be very careful as because things do not match up, mine had burnt areas in the circuit board, jumper wires to make lights work properly. I bought a new board and finex things. With the way things looked, very easily could have started a fire. Will send pics when I can if I can find the old board.

 
Here is a pic of what my circuit board looked like. The speaker wires in pic were run from light to light so they would work properly.





 
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Geoff,

Thank you for your comments - most helpful.

I am leaning towards Rocketman as I don't really want any dramas being so far away.

There is every chance the speedo will not be accurate with 18 inch wheels etc so I will

drive by the head up display.

Appreciate your help.

Mel

 
Geoff,

Thank you for your comments - most helpful.

I am leaning towards Rocketman as I don't really want any dramas being so far away.

There is every chance the speedo will not be accurate with 18 inch wheels etc so I will

drive by the head up display.

Appreciate your help.

Mel
 Mel. Nice to hear from you. I think you'll find the Rocketman's Classic Cougar conversion satisfactory as you keep all the circuit board and orig harness. What I did to make it easy to take out the speedo/tach if necessary, was to connect the power wire, ground and green tach pick-up wire with bullet connectors. I also installed Hi-Po Parts ELITE series II LED bulbs, keeping the original blue domes as I wanted the factory look. NOTE: do not install an LED in the ALT socket. This MUST remain an incandescent 194 bulb. Way too technical for me to explain but that's what is necessary. Below is a pic of my tach conversion. You may notice that there is no brake light. This is because I have a converted front/ rear brake system and the proportioning valve is only used for the front brakes. Rears are on a separate circuit.

As for you speedo being out because of 18" wheels, they do make different gear drives, so there may be one for your size wheels. That way you have a more accurate speedo.

Oh! you may need to find an idiot light housing as a core part, but talk to Bob first. Not sure how much difference in cost there might be without a core exchange.

www.rccinnovations.com

www.hipoparts.com

Keep us posted,

Geoff.

 
Here is a pic of what my circuit board looked like. The speaker wires in pic were run from light to light so they would work properly.



That's awful.  You need to replace the circuit card or consider my alternative: a hard-wired dash cluster harness (https://www.7173mustangs.com/thread-can-the-instrument-cluster-be-hard-wired?highlight=hardwire)

I could have converted your non-tach underdash harness to work with your tach dash that you bought, but you'd still need the 3 gauge center cluster so you could get oil and water temperature gauges. Only RCCI can provide you a tach and in-dash oil and water indicator lamps.

 
Last edited by a moderator:
Hi Mel, try this one - https://www.cjponyparts.com/instrument-cluster-circuit-board-with-tachometer-1971-1973/p/DCB4/

I bought the non-tach type and getting RCC to convert my clock to tach - great bloke to deal with
Hi Oz,

Is that 'Rocketman' you refer to?

Would you mind giving me some more details.

She is all apart now with guards and doors off being

media blasted and coated.

I am trying to build my stock of parts for the interior and dash,

Don from Ohio Mustang is assisting me - have you converted to RH Drive

or not?

Thanks for your help - send me you mobile number so we can talk more.

Merry Christmas.

Melfunctions
Hi Mel

Looks like some members have sorted it for you and as Midlife says he can change your wiring harness if you want to go the full guage/original tach set up.

If you only want a tach the simplest way is with Rocketman

I'm still part way through both restoration and RHD conversion learning the hard way

I've sent you a PM before but will PM my phone number would be good to have a chat

Merry Christmas to all

 
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