[jakes1970ta]

Time to send the Tach Speedo Cluster and the Fuel Gauge Cluster out for restoration. Looking at Instrument Specialties in Rhode Island and D&M in South Carolina to name a couple. Comments and suggestions appreciated. Thx!!

[Ramairnacho]

Following but was referred to redline guaged by my friend Greg. I plan on having speedonrebuolt and getting a 8 grand tac calibrated along with others like oil volts fuel temp plus new circuit board and lights.

[Gator67]

I used autoinstruments.com for my 70 TA about 5-6 years ago. They did a fantastic job. Fairly quick turn around at that time. I think I dealt with a guy named Gentry.

[MDSHARK81]

Any update from Jake or RamAirnacho? Who did you go with, and how were the results? I’m looking at H&H auto electrical (Tachman) in South Carolina or D&M also in South Carolina. Any other input would be appreciated. Especially if someone used the above mentioned shops.

[jakes1970ta]

I went with Instrument Specialties in Rhode Island. Cluster came back better than new. Amazing work. Mailed them in and about a week later got a call with price and timeline

[unruhjonny]

Looks very nice!!

Did they (accidentally?) change your clock knob?
it looks like the first picture has the correct black (two piece) one;
The third and fourth clearly show a later chrome knob.

[jakes1970ta]

My knob was broken off when I sent it in. The clock has been changed out to a quartz clock.

[srmmmm]

D & M did mine and included moving the redline up on the tach

Everything is working fine except for inconsistencies with the tach, but I think it's a dirty signal from the MSD distributer. That gremlin is being chased out now.

Appearance wise they looked brand new though. I'd use him again.

[grd777]

Originally Posted by srmmmm

D & M did mine and included moving the redline up on the tach

Everything is working fine except for inconsistencies with the tach, but I think it's a dirty signal from the MSD distributer. That gremlin is being chased out now.

Appearance wise they looked brand new though. I'd use him again.

have the same issue with my tach let me know how you make out

[Ramairnacho]

Originally Posted by srmmmm

D & M did mine and included moving the redline up on the tach

Everything is working fine except for inconsistencies with the tach, but I think it's a dirty signal from the MSD distributer. That gremlin is being chased out now.

Appearance wise they looked brand new though. I'd use him again.

I am.in the process of restoring my 1970 formula and was told by a redline guages tech that msd or hei will not work on a standard rebuilt tac it must be completely upgraded., but petronix or pints will work fine. I would find out if they did the stock rebuilt on your 1 wire tac or upgraded the tac. If it's a one year only 1 wire tac I would leave alone and either put points back in or get a 8 grand 71-75 2 wire one and have that one upgraded. you can trouble shoot it too by putting points distributor in it and see how tac operates before doing all that. I'm surprised the restoration company didn't mention any of this to you. Also cover the back of the tac center where factory aluminum tape was if not already done when all issues are resolved. There is a magnetic field there that will attract dust and metal fibers and could damage tac. I'm no expert but ask questions and listen. Just trying to help.

[70GS455]

Originally Posted by grd777

have the same issue with my tach let me know how you make out

If it's the MSD 6AL box and your using the dedicated grey tach wire, the issue could be the tach. That signal is a 20% duty cycle square wave, which means it's 80% dwell, or 36 deg dwell. The factory tach will have trouble with 80% dwell as the rpms climb. There are those of us that have modern circuitry available that handle large variations in dwell very well.

[70GS455]

Originally Posted by Ramairnacho

I am.in the process of restoring my 1970 formula and was told by a redline guages tech that msd or hei will not work on a standard rebuilt tac it must be completely upgraded., but petronix or pints will work fine. I would find out if they did the stock rebuilt on your 1 wire tac or upgraded the tac. If it's a one year only 1 wire tac I would leave alone and either put points back in or get a 8 grand 71-75 2 wire one and have that one upgraded. you can trouble shoot it too by putting points distributor in it and see how tac operates before doing all that. I'm surprised the restoration company didn't mention any of this to you. Also cover the back of the tac center where factory aluminum tape was if not already done when all issues are resolved. There is a magnetic field there that will attract dust and metal fibers and could damage tac. I'm no expert but ask questions and listen. Just trying to help.

Depending on whose circuitry is inside the tach, an HEI will work, it's just the voltage stresses are higher and the circuit components need to be selected to handle it properly. An MSD box is a challenge because of the high dwell, but a well designed tach circuit should not have any problems.

[MDSHARK81]

Originally Posted by 70GS455

If it's the MSD 6AL box and your using the dedicated grey tach wire, the issue could be the tach. That signal is a 20% duty cycle square wave, which means it's 80% dwell, or 36 deg dwell. The factory tach will have trouble with 80% dwell as the rpms climb. There are those of us that have modern circuitry available that handle large variations in dwell very well.

Who is “us”, and what are the “modern cricuits” of which you speak?

[70GS455]

Originally Posted by MDSHARK81

Who is “us”, and what are the “modern cricuits” of which you speak?

One would be myself, and any others who repair tachometers. My own proprietary circuit design qualifies, as does any other's design that can accept a wide range of dwell.

[Ramairnacho]

it is my understanding that the modern upgrade is good for msd and hei but if you have a 1970 1 year only 1 wire tac it will.be gutted and will no longer work on points. For this reason I would use the 2 wire tac and save my original one but that's me. once you go modern points will no longer work. I.dont understand why it doesn't and all I know is not to.modernize my 70 tac but good news is 1 can run a petronix with no problem and keep it number matching or points. I'm not building a race car just restoring my 1 st car. if my info is incorrect please correct me
just trying to.help

[MDSHARK81]

I too am restoring my 1st 2nd gen F body. I am learning everyday of the many 1 or two year only parts and processes that were used on our cars. My car being a 71 would also have the one wire tach. My attention now being turned to debugging and getting all systems operational. This unfortunately includes a non operational Tach ( was working prior to restoration). It must have been “handled too much”.

My question to GS455 or any of the others who repair auto electronics either as a hobby or commercial business is do you just replace the 1 wire tach guts to get them to operate with points only? or Do you convert the 1 wire movement to a 2 wire later movement? In which case I think I would use a donor later tach as not to ruin an original one. Just looking at options. Trying to complete the car and have an operating tach, among other things. I would like to find a repair shop familiar with the early cars like ours. My preference would be to send out the whole cluster to repair the clock and tach, as well as test and calibrate the other gauges in the cluster. I appreciate any and all input about your experiences with repair shops.

[Ramairnacho]

Originally Posted by MDSHARK81

I too am restoring my 1st 2nd gen F body. I am learning everyday of the many 1 or two year only parts and processes that were used on our cars. My car being a 71 would also have the one wire tach. My attention now being turned to debugging and getting all systems operational. This unfortunately includes a non operational Tach ( was working prior to restoration). It must have been “handled too much”.

My question to GS455 or any of the others who repair auto electronics either as a hobby or commercial business is do you just replace the 1 wire tach guts to get them to operate with points only? or Do you convert the 1 wire movement to a 2 wire later movement? In which case I think I would use a donor later tach as not to ruin an original one. Just looking at options. Trying to complete the car and have an operating tach, among other things. I would like to find a repair shop familiar with the early cars like ours. My preference would be to send out the whole cluster to repair the clock and tach, as well as test and calibrate the other gauges in the cluster. I appreciate any and all input about your experiences with repair shops.

call redline guages in California. The guy knows his stuff and he can explain to you in detail your options. Look then up on Google if you can not find them let me know

[MDSHARK81]

Redline Gauge works in Santa Clarita, California. Got it. Thank You.

[70GS455]

Originally Posted by MDSHARK81

I too am restoring my 1st 2nd gen F body. I am learning everyday of the many 1 or two year only parts and processes that were used on our cars. My car being a 71 would also have the one wire tach. My attention now being turned to debugging and getting all systems operational. This unfortunately includes a non operational Tach ( was working prior to restoration). It must have been “handled too much”.

My question to GS455 or any of the others who repair auto electronics either as a hobby or commercial business is do you just replace the 1 wire tach guts to get them to operate with points only? or Do you convert the 1 wire movement to a 2 wire later movement? In which case I think I would use a donor later tach as not to ruin an original one. Just looking at options. Trying to complete the car and have an operating tach, among other things. I would like to find a repair shop familiar with the early cars like ours. My preference would be to send out the whole cluster to repair the clock and tach, as well as test and calibrate the other gauges in the cluster. I appreciate any and all input about your experiences with repair shops.

My conversion will allow your tach to operate with only one wire and will be compatible with points, HEI, MSD box with the dedicated tach wire, or any points conversion ignition that is not multi spark. I only replace the circuit board, and depend on the meter movement being good or repairable. I also have a 2 wire circuit board that is compatible with the above listed ignitions, it requires a 12v power source. Anyone tech line that tells you a one wire is not compatible with HEI does not know what the are doing or their design is garbage. I have a master's degree in Electrical Engineering and have been doing this for a minute. My conversions are around $50, and I cannot do much cosmetic work.

[MDSHARK81]

So, after speaking with Redline Gauge Works I’ve decided to have them repair my original cluster ( tach/clock). Thanks Ramair. I removed the unit after dropping the column. My question is upon taking the unit out I noticed that there was a black wire connected to the last bulb on speedo side, top corner not connected to anything? is this a ground wire?, where did/does it attach?, can I just ground it to metal dash frame???
The only other connections were the single tach wire, the main multi plug, and the speedo cable. ( pretty straight forward ).