Help needed with Smiths impulse tacho

[Siggs]

Hey all, I have an old school smiths tacho (RVI5000/00B) I want to fit to my FC but any items I can find on wiring on the net for the tach I have mentions two white wires to connect it in series with the coil but my tach also has two red wires - any ideas

[Glenn 'Stinky' Stankevicius]

Red is usually power, one for the tach and one for the light maybe 

[FireKraka]

Hi Siggs
I was having a look on the net for you but can not find the model number you put up however I agree with Stinky one probably power for the tacho and the other for the light.

I also have a problem with my VDO Royale tacho so if you don't mind Siggs I may as well ask the question here, I had the tacho connected to the 208 I had in the car originally and it worked fine now with the V6 and V6 Conversion wiring harness when I turn the ignition on the tacho goes up to about 1000rpm (eng not started) Light works in it, I've checked the earth any body got an answer.

Regards
Neil H

[FireKraka]

Just answered my own question (isnt the net amazing hey  ), my VDO has dip switches and they have to be configured the right way for electronic ignition vehicle and not for an older car that the tacho senses from the ignition coil.

Regards
Neil H

[FireKraka]

Siggs as I said earlier I have not been able to find your tacho by model number but have come across a document for a "Smiths Impulse Tachometer" I will scan it and email it to you if this is yours then it must be pretty old because the price on the front of the document is 9 pounds 15 shillings.
Let me know if this is the right one (yes to much time on my hands at the moment)

Regards
Neil H

[Siggs]

Almost on a winner !, Thanks for the help, I have wired up and it now either just reads around 800/1200rpm or jumps right up to 8,000rpm with just afew revs, I really don't care if it's accurate bit I'd like to get it reading approx right, any ideas ?

[FireKraka]

Siggs;
What engine are you running? With my VDO it talks about the number of pulses per revolution and that I have to set it to suit I can get it close and will then have to adjust it slightly. I cant remember if yours has dip switches or something on the back of it.
Regards
Neil H

[Siggs]

Hi Neil,
Running 186 with points ignition, the white wires from tach don't have a trace so I went with pot luck, no reading at all, then I had a fiddle and founs a screw on the back with a wire going to it with the marking 4cyl 6cyl and another with 8 cyl. I checked and found this circuit not live so bridged to earth and needle went straight to max revs sp I swapped white wires where I had connected them to the coil, now tach reads either very low and with little response to revs or after fiddling with dash pot at back of tach too responsive jumping to 8,000rpm with estimated 1500 revs on engine with no middle ground. I should also note I got this with a car I parted out, it was in the boot with some other gauges and stuff so I'm not sure it is any good and might be wasting your time and mine ! But as I really want to keep the FC all old school it'd be sweet if I could get it working.

Thanks again for your help

Col

[FireKraka]

Hi Col;
You may have to get it looked at by a instrument shop it may just need some TLC the dash pot may be the problem if it jumps instead of being able to be smoothly adjusted.

Cheers Neil H

[Siggs]

Bugga,
Thanks for the info though.

Col