73 Dash Replacement Project

[KenFirch]

Thanks Dave for the suggestions!  👍  That's quite a set of videos you have up there!

I attached the defrost vent panel to check the clearance between it and the dash.  Looks good.  I should paint that panel, but I'm afraid I won't get the right sheen and won't match the dash.

Did a dry fit into the car to see how it fit, and any clearance issues with the doors, etc.

I still haven't figured out how this car got so much overspray on the inside, shifter boot, wiring near the harness and relays, even some of the diamond tunnel covering.  It wasn't a color change, and no floor or frame work has been done.  What the heck were they trying to accomplish?  

[KenFirch]

Got the center and glove box openings trimmed and ready to glue to the frame.  I tried to generally match how the original dash was trimmed in the openings.

Borrowed a friends solvent based Weldwood contact cement, hopefully it will hold good.

I think these small dimples may be suggested cutting lines, I ended up cutting fairly close to them as I was trimming.

Using stir sticks and clamps to hold overnight.  I've got my 10mm 3/8" socket in the glove box button hole so dash is not getting deformed by the clamp.  I ran out of clamps, so I'll finish the center tomorrow.

Edited September 20, 2022 by KenFirch

[KenFirch]

Got the edges glued, and test fit the center panel and glove box.  Glove box works fine, not more string to pull it open.  Getting new correct fasteners for the center piece.

Now onto the gauges.  I took the clock apart, tested the motor, which works.  I might just try to clean it up and lightly oil with the correct stuff.  Wait time on quartz conversion is 14 weeks, so maybe I'll hunt around for one already done.  Might be nice to hear a ticking clock though.

The tach has never worked in this car since I bought it.  Not see sure what year tach it is, it has a 6400 redline.  And I've got an old one, correct dial I believe.  Pictures below.  Looks like the one on the right in missing the loop wire on back.  

Is there a way to bench test these?  Thanks!

[SteveJ]

My friend, Google, found a link that led me to this: http://www.mgb-stuff.org.uk/tachtest.htm

[Captain Obvious]

11 hours ago, KenFirch said:

Looks like the one on the right in missing the loop wire on back. 

Not quite sure I understand which tach you have (it appears you have two of them?), but the correct tach for your 73 is the style with the loop on the back. The other style (without the loop) will not work in your car without some other modifications.

This is the correct style for your car:

[SteveJ]

Yep, I was talking with @Captain Obvious, and he pointed out the tachometers were different. Apparently someone converted a 260Z/280Z tach to fit into a 240Z. The wing nuts were added to the tachometer

[KenFirch]

On 9/21/2022 at 4:36 AM, SteveJ said:

My friend, Google, found a link that led me to this: http://www.mgb-stuff.org.uk/tachtest.htm

I couldn't get that method to work.  Maybe the newer battery chargers are too smart and figure out there's no battery hooked up to it.

I hooked the 260/280 tach with the single signal feed to my Sunbeam Tiger, which also has a Pertronix.  And it works fine!  It read high at 2000 when the Ford 260 was at 1500, which makes sense.  So, I'm going to move the 7000 redline dial the that newer tach, should be good to go.

Edited September 22, 2022 by KenFirch

[SteveJ]

Yes, you have to fool the charger to get it to start. You can do that by having a jumper to a battery that you pull. However, it sounds like your method worked, so there is that.

Now here's the next question. Has the wiring in your car been modified for the 3 wire tach? The stock wiring in a 240Z is for the 4 wire tach.

[KenFirch]

Yeah, it had 3 wires.   I'm going to have to trace that wire that supposedly goes to the coil.

[SteveJ]

Here's the follow-on question. Did the PO get the resistor installed in the circuit? The design of the tach circuit for the 260Z/280Z 3 wire has a 2.2kOhm 1/2W resistor between the tach and the negative post of the coil.

[KenFirch]

On 9/22/2022 at 5:48 PM, SteveJ said:

Here's the follow-on question. Did the PO get the resistor installed in the circuit? The design of the tach circuit for the 260Z/280Z 3 wire has a 2.2kOhm 1/2W resistor between the tach and the negative post of the coil.

Yeah, I doubt a resistor is there.  Looks like the tach is feeding from the Black/White wire going to the coil.  And reading this thread, it looks like the need for a resistor is sometimes not needed, maybe depending on the electronic ignition used, I don't know.  But something is funky with my tach wiring, I still need to work it out.

On my clock, I stripped it down to the mechanical clock mechanism, cleaned it good, lightly oiled pivots with clock oil, no luck. Took apart motor too, cleaned and oiled.  everything looked okay, worked for awhile, then quits.  Beyond my capability.

So, I ordered this electric clock off of Amazon for $40, and finessed it into the housing.  I thought of just painting the orange hands white, but decided to clip the originals and epoxy them to the new clocks hands.  I may still get some Testor's paint and mix up the right off white shade, and paint the hands.  Plus I'll have to mount a small push button (negative ground signal) somewhere hidden under the dash or in glove box to adjust the time.  I'm running it overnight to see if swinging the little extra weight of the hands affects it's accuracy.

[Captain Obvious]

1 hour ago, KenFirch said:

So, I ordered this electric clock off of Amazon for $40, and finessed it into the housing. 

Does that thing really say "CLOCK" on the front of it?