Tacho conversion

[bloodknock]

Hello People
I'm still battling on. Most of my time since I last spoke has been wrestling with trimming the beast. Installing carpets is a real pain in the proverbial....flat carpets around tight compound curves.....contact adhesive is just what it says on the tin...contact with anything as you fit and its a bugger! I ended up with my hands looking like a werewolf with black carpet pile well and truly adheesed!
Anyway, the other item ocupying my time is installing a RVI - RVC conversion board in my tacho, necessary because the Aldon ignitor I have used in my distributor causes aberations in the tach readings.
I have purchased a conversion from Spiyda which involves stripping the Tacho and replacing the internal electronic board. See photos. The stripdown is not easy, it takes a lot of care and time. The darn thing has been sitting for fourty years glueing itself together. It took some opening up I can tell you, and because of its delicate mechanism you have to take great care not to get dust and muck into it.
The Spiyda board is a nice neat piece of kit which is easy and straight forward to fit. It comes with good instructions and support on the tinterweb. The calibration has been an issue for me, I want to be sure its checked out and functioning correctly before I install it in the car dashboard. I could not get the reccomended calibration technique to work, no matter what I did. I contacted Spiyda by email and had an immediate response offering to take the assembly and calibrate it at no charge other than postage. I have to say that this level of customer support is most reassuring.

[MarkDa]

Bob
Mine seemed to calibrate ok but in the car only goes up to 4k or so.
I haven't got round to complaining to Spiyda yet, sounds like he'll be helpful.
I'm not the only person to have this issue.
Mark

[bloodknock]

Hi Mark
I wasn't aware of issues with this unit, I've seen reports on other forums that it was a good fix for the waving needle syndrome. I didn't want to install it all only having to strip it out to rectify.
Are you saying that yours only reads up to 4k and then sticks or that 4k is full scale range deflection? What ignitor are you using, mines an Aldon? I wonder if there is wave form aberation from ignitor to ignitor. I wish I still had access to my old lab and test gear!
Its amazing how these superficially simple things cascade into periods of pain!
....Fix the access and variability problem of setting points....Fit an electronic module.....module too big to fit under original centrifugal rev limiter....find alternative that will fit into the space available.......realise that the tacho will not work correctly .....locate and fit RVI / RVC conversion to the tacho.......incorporate wiring changes to accomodate tacho change......investigate and repair isuue with tacho as far as possible off vehicle....reinstall not knowing categorically that it will work in real environment. (Car is still three monthsish away from fire up!)
Its like chineese water torture!!!
Regards
Bob

[KevJ+2]

I also couldn't calibrate the Spyida RVC to the waveform, so for a small fee I sent it off to him and he did it for me.
My problem (with electronic distributor) was when I switched off, the rev needle would jump right round so he also included a diode (I think) to solder across the back, which helped.
He really is very helpful and prompt with his replies and good to deal with.

[Grizzly]

My problem (with electronic distributor) was when I switched off, the rev needle would jump right round so he also included a diode (I think) to solder across the back, which helped.

Mine was similar (would jump more on start up) https://www.youtube.com/watch?v=0AmvKE2 ... e=youtu.be ..... even after the diode it has it's moments so after much messing about i found the Ignition coil made a huge difference (Tacho works best with a ballast set up but also works ok with a Bosch Blue 12v coil..... It ran best with the Bosch Blue coil) Lucas 12v Sports coil would make the tacho do all sorts of odd things.

I had the same issue with calibrating from my phone but when i tried the same thing using a Laptop it worked fine.

[MarkDa]

Bob et al
I have an Aldon ignition system with Omex external rev limiter.
The tacho went full scale at cali ration but in the car it's accurate up to 4k but won't go any further.
I'm not the nly person with issue i now know, but over the summer was too busy to take it out and sort it - using the car!
Since then it's been in body shop having some remedial work done.
Here's link to a recent thread:
lotus-electrical-f38/tacho-repair-t41110.html

Mark

[nmauduit]

My problem (with electronic distributor) was when I switched off, the rev needle would jump right round so he also included a diode (I think) to solder across the back, which helped.

Mine was similar (would jump more on start up) https://www.youtube.com/watch?v=0AmvKE2 ... e=youtu.be ..... even after the diode it has it's moments so after much messing about i found the Ignition coil made a huge difference (Tacho works best with a ballast set up but also works ok with a Bosch Blue 12v coil..... It ran best with the Bosch Blue coil) Lucas 12v Sports coil would make the tacho do all sorts of odd things.

I had the same issue with calibrating from my phone but when i tried the same thing using a Laptop it worked fine.

yes, mine does that too (Bosch blue 12V coil on 123 dizzy)... It also does it when I turn the windscreen ventilation on (and sometimes the needle stays stuck at 8500 rpm for minutes, even when the fan is turned back off...), I suspect it is an issue of stability within the module, and with strong input power variations (like during cranking ... or in my case using the fan possibly via a somewhat degraded piece of wiring behind the dash) then an amplifier gets stuck off its normal operating regime. I acknowledge the fact that they were helpful and very friendly in communicating, but the solution is not as bulletproof as I would have hoped : my next tacho job I'll try to fix it first, to assess that route further before altering it with a module. Also I somehow have the feeling that there is a bit of a lag before the response with the module... I'd like to check that against a stock tacho.

[LaikaTheDog]

I fitted a spidya.
Couldn't get it to calibrate
Spoke to spidya and they sent me a pre calibrated straight swap.
Works perfectly with my electronic ignition.
Good kit and excellent service.

[Mr.Gale]

I bought one and could never get it to work properly. emailed Spiyda back & forth ended up they wanted me to send them my tach and they would fix it. Nice of them to make the offer but I'm in the US and the additional cost and time it would take I declined.

Mr.G

[prezoom]

Same experience.

[ElanDNA]

I fitted a spidya.
Couldn't get it to calibrate
Spoke to spidya and they sent me a pre calibrated straight swap.
Works perfectly with my electronic ignition.
Good kit and excellent service.

Hi
I fitted quickly a spidya-conversion too.
See date of pics. It's a version 2016
So like I remember, it needed then not more than two hours.
Calibrated with my old LG-Phone and controlled at crankshaft with an optical tacho.

Works perfect with my EFI

Cheers Urs

[bloodknock]

Hello folks
Just had my Tacho calibrated by Chris at Spiyda, he also checked it out and finished assembling it. The job was turned around in two days, fantastic service at a very reasonable charge. Just wish all of the companies had the same customer service ethic. Would not hesitate to recommend the company to you guys.
Regards
Bob

[Donels]

Try Speedograph-Richfield. I have used them before for a tachometer conversion to use an Aldon ignitor.