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Willcox New Tach Board Installation Video 1975-1977

Old 02-16-2010, 07:25 PM
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Default Willcox New Tach Board Installation Video 1975-1977

Hey Guys.. here is another one for you to laugh with me on...

This is the new Tachometer board installation video we just did. We kind of tossed this one together the past two days trying to help a customer understand the zero set. After six attempts.. we just decided we would let the video fly and shoot from the hip. Seems to have turned out ok, but I did find a few corrections that I'll make the next time around.

I'll try to do a better one when time permits.

Willcox

Old 02-17-2010, 10:23 PM
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RIO68
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Thanks guys! Learned a bunch I now know how to check my tach becuase I'm sure it is off and now I know what to do.
Old 02-18-2010, 01:23 AM
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No problem Rio!

Willcox
Old 02-18-2010, 11:45 AM
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Default Much thanks! Super job!

Much thanks and Super job! Info like this is just super, I wish I had had this video when I replaced my tach board.

(I took my needle off and pushed it back on more times than you though!)
Old 02-18-2010, 01:26 PM
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Mercury.. I got lucky...

Willcox
Old 02-18-2010, 09:53 PM
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Thetre's a few things to always keep in mind:

*calibration tracking. Although the zero set is done; always check the calibration through the entire range. I've seen too many meter movements that will show accurately at 1000rpm... but be off at 5000. It's the meters fault - not the replacement circuit board.

*due to the above finding, I'd never suggest buying a "pre-calibrated" board and install it yourself. There's too much variation between the meter movements... especially for ones that have age on them (don't they all these days ???)
Old 02-18-2010, 10:43 PM
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Mike,

You are 100 percent correct! The condition of the movement is most critical when setting the calibration. The sign and co-sine outputs of our boards were determined from original tach boards and their corresponding outputs.

One thing I didn't cover was a quick way to tell if the movement is missing oil and that is to just tilt the gauge forward to backwards. If the needle moves fluently then the dampening fluid is gone from the gauge

If you have a tach that is in horrible condition, and say the dampening fluid is all but missing from the gauge your readings will vary! A slight mistake in the zero set and the reading will vary as well. To compound this issue if you'll take a look at the video we did on the 1978-1982 tachometer. The reproduction board performed better than the original board. This happens, there really is nothing we can do about it. We have to calibrate the boards, you can't just send one out with nothing on it since most customers can install a board and in most cases it will be very close.

There are variances between tach to tach and this is one reason we always suggest testing the tachometer before installing it especially on a 1975-1977 car. One can spend all day removing the tach from this car.

One thing that was most critical to us was the lower end readings say between 700, 2000 and 3000 rpms. Most customers are aware of what RPM's the car should idle at and most customers are aware of what the cruising RPM's are on his car. At least I know what my cars turn at 60-70 mph. However, most people that hit 3000 are only hitting it for a brief moment and the 4000 rpm guys are usually flying by this mark if at all which makes getting a reading while driving the car pretty hard. But the 700-2000 and 2500 guys.. they will know instantly if there is a problem.

So basically, the board should be more accurate than a GM board, and if they are off due to a poor condition movement, there is a 15 turn pot installed for adjustments.

One thing we definitely wanted to stay away from was the el'cheepo 1 turn pot used on other boards! In testing we found that simply dropping the board on the table could change the reading and basically because the 1 turn pot was so sensitive to movement and so cheaply made! I stated in the video that you can tap on the 1 turn with your finger and the output will change. The 15 turn pot cost more money, but in the end it is a better product.

Willcox

Last edited by Willcox Corvette; 02-18-2010 at 10:50 PM.
Old 02-19-2010, 07:43 PM
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ttt
Old 02-19-2010, 08:33 PM
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So basically, the board should be more accurate than a GM board, and if they are off due to a poor condition movement, there is a 15 turn pot installed for adjustments.
the GM board... with the carbon "scratch" calibrators ???

I worked at a Delco Electronics repair center for about 5 years... actually repairing 1975 thru 1981 tachometers when they were still under warranty; but i'm not old... Ok ???



yep, those OEM GM boards were a joke
Old 02-20-2010, 02:05 AM
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Mike-

Honestly, you have to love them for what they were! For their day and place in time they were really high tech!

Every time I look at one of those original boards, I look for the scratch lines... I'm not sure why, but I do! Call it intrigued maybe.. no explanation for it at all....

Ernie
Old 02-20-2010, 08:42 PM
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Originally Posted by Willcox Corvette
Mike-

Honestly, you have to love them for what they were! For their day and place in time they were really high tech!

Every time I look at one of those original boards, I look for the scratch lines... I'm not sure why, but I do! Call it intrigued maybe.. no explanation for it at all....

Ernie
Ernie, exchange price on a tach 77 model? Checked mine and sometimes it goes to zero then again it only goes back to about 600 or so not zero???? Most times it goes back only to 600.
Old 02-21-2010, 01:11 PM
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Rio-

You can install this, it's not hard once the tach is out! I don't do the tachs on exchange.. but if you want to send yours in i an install and match calibrate it.

Willcox
Old 02-23-2010, 09:39 PM
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Last bump for these!
Old 02-26-2010, 02:56 PM
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I am glad to see that I did everything okay as I finished fixing my tach about 2 weeks ago, just before this release. I was able to replace the face of a 74 with the electronics off of a 75. I've got a question. What are the odds that my tach board from an original 75 is still working? I looked at it an did not notice any burn marks. I was able to zero it, but am unable to test it, because my engine is apart. Should I just go and buy a new tach board and install it, or do you think the original is still okay? What are the odds that the original will not work one day? How about the new tach board? Do they fry as well? Where is the best place to buy a new tach board, if that is your recommendation?
Old 03-03-2010, 02:58 PM
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Anyone have an answer to the above question yet?
Old 03-04-2010, 05:11 PM
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Don't know for sure but seems to me that as much work as it is to pull these things a new board isn't a bad option?????? Kinda like insurance???
Old 03-04-2010, 07:55 PM
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Originally Posted by rjag
I am glad to see that I did everything okay as I finished fixing my tach about 2 weeks ago, just before this release. I was able to replace the face of a 74 with the electronics off of a 75. I've got a question. What are the odds that my tach board from an original 75 is still working? I looked at it an did not notice any burn marks. I was able to zero it, but am unable to test it, because my engine is apart. Should I just go and buy a new tach board and install it, or do you think the original is still okay? What are the odds that the original will not work one day? How about the new tach board? Do they fry as well? Where is the best place to buy a new tach board, if that is your recommendation?
On a 1975-1977 car there is no way I would go to the trouble to install the tach without testing it! The work to install the tach is way to long to justify putting in a bad tach.

The odds the original board is working.... crap shoot here too! You really should find a way to test the tach before doing the installation. If nothing else.... send the tach to us and we can test it for you.

How about the new board? Do they fry.... Yeah anything can be fried! There are filters on the board to help prevent this, but it is possible.

Where is the best place to buy a new board.... http://willcoxcorvette.com/advanced_...&keywords=tach

We make these boards right here in house and they are the best board on the market!

Willcox

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To Willcox New Tach Board Installation Video 1975-1977

Old 04-13-2010, 08:43 PM
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RIO68
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Default tach board

Originally Posted by Willcox Corvette
No problem Rio!

Willcox
Ernie, got a board and have a problem. Tried to send a PM but couldn't.
PM me w/contact info.

Thanks!
Old 10-09-2015, 10:17 PM
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Old 09-17-2016, 10:17 PM
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