[Healeys] Fw: BJ8 Tacho Upgrade and Digital Speedos

[michael.salter at gmail.com]

Wow Roger... that is seriously high tech!!

Wonder if there is any way to make that stepper motor tach take readings every 0.5 seconds to make its action look like those ever so cool "chronometric" tachs used in '50s race cars.

Michael S 

BN1 #174.





On Mon, Jul 11, 2016 at 10:55 AM -0400, "Roger Grace" <roggrace at telus.net> wrote:









































Recently went to Wales to collect my stepper motor converted tacho. and now 
installed.
So far very good; nice bright red ignition led indicator and led back 
lights.
They also changed the face text from “positive earth” to negative – nice 
touch.
Proper digital stepper motor (BTW Nisonger and others ? don't do this) so 
no more calibration or analog issues, or current pulses.  No mechanical 
hairspring type movement.
Input is from from the CB on the coil and a new wire has to be installed; a 
little sensitive to routing. I use a Pertronix.
No doubt they could also convert a mechanical tacho. to digital as 
well.
 
Now digital speedos.
 
There are 2 options.
 
The first, that I have ordered, is to cut the speedo. cable at a convenient 
spot and install a pulse transducer. My thinking is that this is preferable and 
easier than installing a magnetic type on the drive shaft.
They are building me a RVI instrument that will be near identical to the 
original Smiths with dished face, but with a LED display in place of the odo and 
trip.
This will have a modern digital stepper motor drive and hopefully be stable 
and accurate. High beam indicator as before. Easy, accurate calibration.
I have ordered this as MPH and so my plan, for driving in Canada will be to 
calibrate for 140 MPH as actually 140 kPH. This is easy to do and when in US 
will revert back to MPH. Only problem is that the total odo will be affected; 
may just use the trip to keep track or just stick with MPH.
Will report back after receipt.
 
Second option is to use an electronic digital cable drive to drive the 
original magnetic speedo with original odo. and trip, if preserving the original 
look is important. This also uses the same pulse transducer as per the LCD one. 
The pulses now drive a mini digital brushless dc motor in a separate box with 
electronic speed control. This box has a speedo cable output (usually short) so 
electronic scaling is easy but it is still a mechanical magnetic cup type drive. 
Hopefully, with no long cable and sable pulses the typical speedo blips etc will 
be eliminated. There is also some electronic filtering. This is the more 
expensive option and they insist they will only sell this option if you have the 
original speedo refurbished by them as well. This in the final stages of 
development and they have a large contract to fulfill in next 2 months, so 
realistically by Nov. time.
 
As I will still have my original speedo. so if not happy with the LCD above 
could resort to this solution.
 
rg
 
From: Roger Grace 



Sent: Friday, May 6, 2016 8:33 AM
To: Healey List 
Subject: BJ8 Tacho Upgrade
 



Seriously thinking of getting my moving coil tacho. upgraded to a modern 
stepper motor type movement, retaining the original face and case.
Speedy Cables in Wales offer this.
So, wondering (UK listers ?) if anyone has had this done and any comments 
about this type of conversion.
Are there perhaps any US companies that do this as well ?
Tkx
rg 






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