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Ok... so here is what I am trying to accomplish. It's not motorcycle related, but since you guys know tachs more than vintage car people... my guess is that I will get the best advice here.
I am trying to put a tachometer on a 1925 Derby-built Silver Ghost. It is an 8 Liter (roughly) six cylinder engine with both a magneto and a distributor ignition that work simultaneously (12 plugs, six cylinders) The car has no provision to take a mechanical cable drive off from cam, dynamo, distributor, etc. to power a cable-operated tachometer. In "theory" I could put a gear PTO on the magneto drive and use that, but that is kludgy and raises all kinds of issues mechanically.
The ideal solution is to use an electronic tachometer of some kind. Here's my rub... my redline is 1750 RPM, so almost any electronic tach is going to register almost no needle sweep. So even if I put a modern gauge in, a 10,000 RPM tach that generally runs at 600 RPM (and idles at about 100 RPM) is pretty much useless.
There are some lower RPM tachometers out there, including some older Sun units. One I have seen that looks great is for sale on eBay right now, but it is a four-cylinder unit and I am not sure if it can be adapted... or if they made an identical unit for a six. In terms of 'look and feel' this is an ideal unit, even though it appears to need an occasional battery change.
http://www.ebay.com/itm/171167952358...#ht_643wt_1158
There are also some units out there such as this panel meters unit, which is utterly perfect, but I don't know how to "drive it" and feed input into it... or whether it's even possible?
http://www.ebay.com/itm/360768634661...#ht_261wt_1158
So interested in any thoughts... or leads as to who can set something like this up in as 'bolt-on' a manner as possible. I can't imagine it's not a solvable problem. I just suck at electrical things.
Cheers,
Sirhr
I am trying to put a tachometer on a 1925 Derby-built Silver Ghost. It is an 8 Liter (roughly) six cylinder engine with both a magneto and a distributor ignition that work simultaneously (12 plugs, six cylinders) The car has no provision to take a mechanical cable drive off from cam, dynamo, distributor, etc. to power a cable-operated tachometer. In "theory" I could put a gear PTO on the magneto drive and use that, but that is kludgy and raises all kinds of issues mechanically.
The ideal solution is to use an electronic tachometer of some kind. Here's my rub... my redline is 1750 RPM, so almost any electronic tach is going to register almost no needle sweep. So even if I put a modern gauge in, a 10,000 RPM tach that generally runs at 600 RPM (and idles at about 100 RPM) is pretty much useless.
There are some lower RPM tachometers out there, including some older Sun units. One I have seen that looks great is for sale on eBay right now, but it is a four-cylinder unit and I am not sure if it can be adapted... or if they made an identical unit for a six. In terms of 'look and feel' this is an ideal unit, even though it appears to need an occasional battery change.
http://www.ebay.com/itm/171167952358...#ht_643wt_1158
There are also some units out there such as this panel meters unit, which is utterly perfect, but I don't know how to "drive it" and feed input into it... or whether it's even possible?
http://www.ebay.com/itm/360768634661...#ht_261wt_1158
So interested in any thoughts... or leads as to who can set something like this up in as 'bolt-on' a manner as possible. I can't imagine it's not a solvable problem. I just suck at electrical things.
Cheers,
Sirhr
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