How to Remove Tach?

A

Seymour Snerd

Lifetime Supporter
A couple friends both have dead or dying Tachometers in their SPFs and need to check the wiring at the back. No doubt I will to given my recent experience with the start button. It looks like, and we've been told, that it's quite difficult to get out. Have any of you done so? Can you provide advice, hints, tricks, or anything?

Thanks in advance,
Alan.
 
P2164

Jack Houpe

GT40s Supporter
awatkins said:
Already have those....:sad: and the cuts to go with them....

Did you drop the steering column?
Click to expand...

Sorry Allen, I didn't see your reply on "new posts", no I didn't drop the column and to be honest can't remember exactly the procedure. You know Kirby Schradars whole dash comes out, mine is siliconed to the front window I think. It sure would be nice to pull it out and get to things like his.
 
A

Seymour Snerd

Lifetime Supporter
P2164 said:
You know Kirby Schradars whole dash comes out, mine is siliconed to the front window I think. It sure would be nice to pull it out and get to things like his.
Click to expand...

That's for sure. I wonder if it needs to be siliconed in. IOW if we took the one-time step of slicing the silicone would we introduce any problems? Is the "siliconed dash" like the "bent speedometer cable" where the builder in South Africa is justing being stupid and/or sloppy?
 
P2164

Jack Houpe

GT40s Supporter
Isn't it strange Steve that certain cars do or do not have different things. My car and Mike Trusty's car (#2165, mine #2164) have never had wheel bearing issues, but our dash will not come out. Kirby's car had bearing problems and his whole dash will come out. Sure would like to see who worked on these cars.

Alan (not Allen, sorry) my speedo cable was bent 90 degrees and sheared off so I put in the speed hut programable unit, no more cables just a couple wires.
 
S

DaveM

Where do you see the silicone? My car has extra windscreen sealant that is near the front of my dash, but I haven't seen silicone at any dash edge. Of course I've never tried to move my dash either. Jack you say no wheel bearing problems. Have you had to at least adjust the bearings?
 
A

Seymour Snerd

Lifetime Supporter
P2164 said:
Isn't it strange Steve that certain cars do or do not have different things....... my speedo cable was bent 90 degrees and sheared off .
Click to expand...

I know this sounds paranoid but, my car has different issues between left side and right side.... So I think two people built it.

I think they all have the bent cable (?); thanks to you I knew to look for that and have already switched to the GPS speedo.
 
A

Seymour Snerd

Lifetime Supporter
Mark IV said:
awatkins said:
I think they all have the bent cable (?)QUOTE]

No because the chassis I have in stock has NO cable! At least they didn't bend it! But we will install a cable should the customer want a cable driven system.
Click to expand...

Ah, so that's where I went wrong! So if I want one without wheel bearing problems, just get one without wheel bearings! How much does that option cost? :lipsrsealed:
Click to expand...
 
P2164

Jack Houpe

GT40s Supporter
SwiftDB4 said:
Where do you see the silicone? My car has extra windscreen sealant that is near the front of my dash, but I haven't seen silicone at any dash edge. Of course I've never tried to move my dash either. Jack you say no wheel bearing problems. Have you had to at least adjust the bearings?
Click to expand...
Its caked from the front window to the dash. No wheel bearing problems and I go over the car with a fine tooth comb before every open road race. I've done big bend open road race 3 times and thought if something was going to get loose it would have by now. Almost 9,000 miles on the car and never had to adjust them.
 
Mark IV

Rick Muck- Mark IV

GT40s Sponsor
Supporter
fsts2k said:
Anyone know if the Cobra's have this many inconsistencies or is it only the GT40s?

Kevin
Click to expand...

The MK IIIs ("Cobra") are pretty well bullet proof. The GT40s have had some teething issues but as I always say, they are a 1964 racing car and not a Lexus. Some assembly required, batteries not included.

A good dealer prep will reduce the number of issues that an owner will encounter, but if you don't know which end of a screwdriver to hold, this is NOT the car for you.
 
A

Seymour Snerd

Lifetime Supporter
Rick --


You mean "some re-assembly required."

Which end of a screwdriver to hold? Well, let's see.... If I were in the same room with the guy(s) that put mine together I'd be holding it like the guy in the shower scene of "Psycho."

Just kidding; I love P2160. I just hope for the sake of the installer community, and especially the DIY sector, that the baby teeth are all in and we're no long nursing....
 
A

Seymour Snerd

Lifetime Supporter
awatkins said:
A couple friends both have dead or dying Tachometers in their SPFs and need to check the wiring at the back. No doubt I will to given my recent experience with the start button. It looks like, and we've been told, that it's quite difficult to get out. Have any of you done so? Can you provide advice, hints, tricks, or anything?
Click to expand...

This time I got to answer my own question, courtesy of a turn signal dash indicator light that would not work. I could tell by "acoustic localization" that my turn signal flasher relay was above the tach somewhere. And I had isolated the problem enough to be 90% certain it was with or near the flasher unit. So, here's how you get your tachometer out. It was very difficult.

  1. You need to drop the steering column; this is easy. To start, remove both switch plates on either side of the tach.
  2. In the cavity behind those plates you will see either end of an 8mm bolt-nut pair that holds up the rear end of the steering column. I needed a 13mm deep socket on the nut (LHS) end and a 13 mm ratchet box-end on the head of the bolt. After a seemingly interminable series of 15-degree wrench motions the nut comes off. If you can pull bolt out, do so. If not, wait a couple steps.
  3. About a foot forward the steering column is supported by two nut-bolt pairs, although this time the bolt is a short allen-head. Removed both of those. Having the column somewhat loose in front now helps removed the rearward bolt.
  4. The column can now be laid down on the floor but it will try to pull the turn signal switch wiring with it; disconnect the white plug if needed to drop it to the floor.
  5. Looking up at the bottom of the tachometer now exposed, you will see the lower of the two thumb nuts that retain it against the usual square-U bracket across the rear of the tach. In my case there was another instance (the speedo cable being the other) of the damage the factory did by carelessly shoving the dashboard into place. This jammed that thumb nut against some chassis sheet metal, and pinched the tach wiring, forcefully enough to bend the lower tach mounting stud. So, I bent that sheet metal away with a screw driver, and also bent away that leg of the U-bracket to release the tension on the thumbnut. Then (with the tip of a screwdriver) I unscrewed the nut as far as I could until it hit the threads that were damaged by the dash installation. Now I resorted to a large needle nose pliers to undo the nut about 10-degrees at a time. This took a long time.
  6. The upper thumb nut is of course diametrically opposite the one just removed, at the very top. It looks inaccessible, but you can actually reach it with your fingers via the lower opening between dash and frame if you have medium or smaller hands and are agressive, although you probably want to pull the turn signal and alternator warning lamps out of their sockets to give you more room. I did that through the oil pressure gauge hole because I already had it out. I don't know if this can be done without removing the OP gauge first, but it's worth a try.
  7. The only wiring to the tach is a rectangular plug into its back, which is easily removed. The wiring was wire-tied to the U-bracket, however, which could have been a problem. Proceed cautiously pulling the tach out.
The root cause of all the difficulty is that there is some horizontal frame sheet metal that needs to be cut back another 1/4" or so to clear the rear of the tach, the tach harness, and the lower thumb nut. This is what jammed the back of the tach, the wiring, and messed up the thumb nut and stud. You might be lucky and not have that problem.

Just to finish my story, my flasher relay was shoved into the upper fold of the dash, so it was about as inaccessible as you could possibly make it. Just a factory guy being ornery I guess. Turns out the female faston terminal for the dash light was just a little loose on the flasher terminal.

The minor side benefit of all this is that I found, with the tach wiring, the forward end of the optional (pink) oil pressure warning light wire. I always wondered where that was.

I don't know yet how I'm going to retain the tach because getting the two thumb nuts started looks very difficult. I may just invent some other way of retaining the tach. I'd love to hear any suggestions. I will report back one way or another.
 
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J

Jac Mac

Just cut the legs off the U bracket, put a short bungee cord with closed loop on what remains of the U bracket & hook the other end of the bungee onto something more accessable behind the dash area, use one of your non reqd band-aids to stop the speedo from spinning in the panel..:)
 
A

Seymour Snerd

Lifetime Supporter
jac mac said:
Just cut the legs off the U bracket, put a short bungee cord with closed loop on what remains of the U bracket & hook the other end of the bungee onto something more accessable behind the dash area, use one of your non reqd band-aids to stop the speedo from spinning in the panel..:)
Click to expand...

Good idea; thanks.

(went away, had an idea, and came back)

I was trying to think of how this "ought" to be done, and it seems to me these instruments could be mounted from the front in "bayonet" fashion. This would require adding a couple ~1/16" ears on a diameter (the flange and rubber ring are about 1/16" thick radially) cutting the corresponding notches in the dash opening and adding a stop on the back of the dash say 15 degrees clockwise from the notches. The ears would be say, 1" x 1/4" strip of ~22 ga sheet steel, with the last 1/16" bent at a sharp right angle, and epoxied or riveted to the side of the instrument case. If the gap between ear and rubber ring is just under the thickness of the dash material (~1/16" fiberglass) the compression and friction of the rubber ring might eliminate the need for the stop.

Yeah, well, I think I'll go get a couple bungees....
 
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A

Seymour Snerd

Lifetime Supporter
Just some minor details as followup:

What I said above about the frame needing to cut back more to clear the tachometer is not true. The interference is only between the lower tachometer stud and one edge of the frame. The tachometer studs are far longer than they need to be anyway, so cutting about 3/16" off these solves the clearance problem and makes for less turning of the thumb nuts. The stud threads are M4-0.7.

My current plan for mounting the tach is a variant of Jac's suggestion. I think I will dispense with the U-bracket altogether, and attach each end of a ~8" piece of SS safety wire to each stud. This results in a loop that I can then pull on with a small spring anchored somehwere forward on the sheet metal. Possibly I will just use another length of safety wire in place of the spring, forming the base of a Y that is anchored to a sheet metal screw in the frame, and let the flexibility in the dash, etc., provide the clamping force.
 
A

Seymour Snerd

Lifetime Supporter
The safety wire scheme works pretty well. In the case of the oil pressure and tachometer gauges there is no accessible place behind them to tie off a bungee cord, spring or wire. So in each case I drilled ~1/8" hole in the panel directly behind the center of the instrument, fed the safety wire through, and then pulled hard on that wire to seat the gauge, and bent it 90 degrees against the edge of the hole. It's important that the hole be centered relative to the gauge; otherwise it will tend to hold the gauge cocked in it's hole. Then just wrap the wire around a suitably placed screw. No more fighting with thumb nuts!
 
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