Tach error
Pro
Joined: May 2004
Posts: 702
Likes: 1
From: Sealy TX
St. Jude Donor 06-'07
Drifting
Joined: Nov 2003
Posts: 1,634
Likes: 4
From: Northern NJ
St. Jude Donor '04 & '05
It has been my experience that many of the aftermarket tach replacement boards do not work properly. The chip on the original board is obsolete so the aftermarket boards use a similar but different design. Sometimes it works OK, other times not. Usually when there is an issue, the tach displays too high. However I've seen various other issues too w/the aftermarket boards.
It is possible your old board can be repaired which if it can, is the best option. If you PM me I can give you further details on this.
Good Luck!
It is possible your old board can be repaired which if it can, is the best option. If you PM me I can give you further details on this.
Good Luck!
Heel & Toe
Joined: Jan 2006
Posts: 23
Likes: 0
From: Benson Mn
Tach
I have installed four different tach boards from three different suppliers and sent my whole unit in once to have it calibrated. The end result is it still is up to 800 rpms short of what the actual rpms are according to a hand held unit which I have verified as accurate. 
I give up. I am going to try and fix my old tach board. But for now I am going enjoy the driving season and worry about it this winter. These boards came from Wilcox, Mid America and Ecklers
I give up. I am going to try and fix my old tach board. But for now I am going enjoy the driving season and worry about it this winter. These boards came from Wilcox, Mid America and Ecklers
Drifting
Joined: Nov 2003
Posts: 1,634
Likes: 4
From: Northern NJ
St. Jude Donor '04 & '05
However that said, it shouldn't be off 800 RPM across the board. Hard to believe that a tech left it this far off. I'm sure it was aligned using an accurate signal generator to provide the correct pulses which makes me wonder if the issue is really the signal being supplied to it. Are you using a tach filter to eliminate/reduce any extra pulses that may be fooling the tach into thinking the engine is running faster than it is?
Instructor
Joined: Oct 2006
Posts: 219
Likes: 0
From: Jupiter FL
I have installed four different tach boards from three different suppliers and sent my whole unit in once to have it calibrated. The end result is it still is up to 800 rpms short of what the actual rpms are according to a hand held unit which I have verified as accurate. I give up. I am going to try and fix my old tach board. But for now I am going enjoy the driving season and worry about it this winter. These boards came from Wilcox, Mid America and Ecklers
I give up. I am going to try and fix my old tach board. But for now I am going enjoy the driving season and worry about it this winter. These boards came from Wilcox, Mid America and EcklersYou have to make sure on those tach boards that you get the little fiber washers on right. The only place I go for tach boards is J.Gardners Electronic tach repair up in PA. He makes the boards himself, they're not mass produced overseas and they're the best working boards I've seen.
Heel & Toe
Joined: Jan 2006
Posts: 23
Likes: 0
From: Benson Mn
Tach
Yes, I have a new tach filter and the old tach worked fine some of the time and appearred to be accurate. I thought I would replace the board so it would work all the time, which it does it just isn't accurate. Wilcox said they would "calibrate" it for me and I should of asked more questions on how they were going do that. Sorry didn't mean to hijack your thread 76greybeard. Thanks for the input ACECO.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Simple, if we have a board that is not calibrated or working properly, you can send the tach to us and we will calibrate it at our expense. If it’s our board, and it’s not right we will repair it free as long as the board is the problem.
We have the equipment in house to calibrate any tach from 53-82.
Regards,
Willcox Inc.
We have the equipment in house to calibrate any tach from 53-82.
Regards,
Willcox Inc.
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Instructor
Joined: Oct 2006
Posts: 219
Likes: 0
From: Jupiter FL
Also the meter head itself is liquid filled with a damping fluid. Sometimes this dries out and makes the tach act erratically, and it has to be re-damped. Not a problem if calibrating doesn't fix it.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
We had one of these recently, but it's rare! The oil can leak from the pedistal container and/or dry out. This is more common with the mid year small gauges and even the 68-72 cars. But it is possible!