Mechanical tachometer question.

I'm trying to use a nostalgic tachometer with a cable drive on a modern engine (CT525 LS3 Chevy) and am wondering if there is a drive kit that would allow me to accomplish this. Thanks in advance.
 
Just a thought but why not use one of the current electronic "Classic" tacho's on the market. There are a few around now with original 60's style Smiths faces and they operate with a "Chronometric" style needle movement below a set RPM, say 3000. Above this they revert to a normal electronic tacho style, much less annoying when on the road. Without fear of advertising, Farringdons and Stack I think both offer this type in their current ranges. Other than that you'd be looking at a custom take-off for the cable drive as this would normally come from a take-off on the dizzy shaft.

Hope this helps

Darren
 

Jim Rosenthal

Supporter
Most of these are driven off the distributor, like on older Vettes. That said, they aren't real reliable and running the cable to the engine from the dash on a mid-engine car makes for a long cable and a finicky setup. I have a Smiths tacho which runs perfectly off my MSD distributor and it's all electronic. And it looks the part. I had the best luck with the Smiths guys in the Midwest, the guys in New York are not real helpful and kind of rude.

If you are determined to do this, I think MSD do make tach-drive distributors, and they could probably give you some suggestions.
 

Seymour Snerd

Lifetime Supporter
..., I think MSD do make tach-drive distributors, and they could probably give you some suggestions.
That sounds like the closest feasible solution to me... I've never seen an "add this to your existing distributor" cable drive.

The only even vaguely similar idea I had was to get a cam-drive setup intended for driving a fuel pump or dry sump pump off your camshaft (I know those exist), and then adapt the cable to that (somehow).

The other "traditional" way of solving this problem is to ditch the cable and the guts of the tachometer, keep the case, face and needle, and put in the guts of an eletronic tachometer using the original needle.

Wish I had a better idea....
 

Jim Rosenthal

Supporter
I don't know how reliable mechanical tachos are- I think it depends on what is driving them. I would guess that distributor drive is more reliable than other setups- like vintage Vettes had generator-driven tachs, off the back of the generator, which weren't real accurate. My 59 Vette (I used to be a Corvette fancier until I saw the light) had a tach drive distributor; there was a little set of gears and a cable connection and it all ran into the dashboard to the tach. But the distance was short and there wasn't a lot of play in the cable. When you are talking about going from the front of the engine to the passenger space and dashboard, it gets a lot longer and a lot whippier. If that's the word.
 
Thanks for the responses guys. You are right, it is cumbersome at best and a step backwards for no good reason at worst. I really like the Jones or Moroso tachs and that's what I thought would fit best with the spirit of my project. I will go a different direction unless a sensible solution comes forth.
 
Pegasus has a right-angle drive that can either work off the camshaft, through a hole in the front cover; the crankshaft through the same, or I'm thinking I can use it with a dry sump oil pump drive or water pump and some clever bracketry. I'm going to give it a shot.
 
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