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Jones/Moroso Mechanical Tach Cable

I was gonna get some measurements from my tachs and cable, went looking for them, and darned if i cant find em! That kind of stuff drives me NUTS! I know where their supposed to be, they arent there.
Anyway, yes when i was using mine, they tended to bounce a bit at the bottom of the scale, smoothed out as rpm climbed.
 
FOUND EM! I said not finding stuff drives me crazy.
Anyway, my cable housing is 6'2"the cable is an extra 1/2" on the tach end, and 1" on the distributor end.
Both tachs have a male square driveshaft, .183-.185. The tach end of the cable is a female square, .187-188.
The distributor end has a round end with a tang. The round end is .156, at the tang, the added height makes it.195, the tang is .500 long.
Now, since it has been so long sice i used them, im gonna lube the cable and chuck em up in a drill and see what happens!
(Also, as a side note, found an old corvette tach drive distributor in my stash. It uses a completely different drive than the mopar. Its hard to tell, looks like a round shaft with a flat spot. Could be wrong)
 
Just tested both of my moroso tachs, with an electric drill.
The little one was a little nervous at 1000 to 1200, but rock solid at 1500. Im pleased.
The big one, which i like much better, was insane. The needle wildly bounced all over (tattletale showing 11000 on a 9000 tach!). Having nothing to lose, i squirted some PB blaster in around the tach driveshaft, let it soak a bit and tried again. Still bouncing around a bit, but wait! It settled right down to a nice steady reading! Cool!

Now i just have to find out why one says maximum rpm of the drill motor is 1500, and the other says 2100. Oops!
 
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I have two, Jones Tachs. The one I don't want to use became steady with the drill spinning the distributor end. The one I want to use is still bouncing wildly. My drill is a 1500 RPM unit. May have to try a die grinder to get more RPM. I'm nervous to lube the tach as it says right on the tach..."Do Not Lube"!
 
I'll mess with it more tonight. Anyone know why you're not supposed to lube them? Seems a mechanical piece would be happy with it.
 
Graphite is what I have always used on them. Hey any tight bends in the cable routing.
 
HALIFAXHOPS said:
Graphite is what I have always used on them. Hey any tight bends in the cable routing.
Click to expand...
Nope. Cable is almost completely straight for testing. It will have some small bends when installed though.
 
All i know is that my big moroso (i think they are all built by Jones-Motrola, except SW of course) was fluctuating wildly, i shot some pb blaster in it, and it smoothed out in about a minute.
I dont know if i wrecked it or not, but it sure started out not working, and now it does.
 
Just a thought. Maybe they dont want you to lube to keep from getting lube on the gauge face or on the inside of the lens?
 
My mechanical tach was the Direct Connection SW 9000 RPM version. I have the iron tach drive electronic distributor. I was always rock solid, no bounce at any RPM. In nearly 20 years I think I lubed the cable once with spray silicone & let it hang for a while. Changed the cable length a couple times at the local speedometer shop. I'd still be running that setup, but Auto Meter that came with my Satellite seems to work real well. Still run the old Hemi tach drive distributor though.
 
Yep. I have the SW gauge in our '64 Fury Vert'. It works great, and never bounces at all.
 
@HEMI-ITIS thanks for the speedo its a great sw , i have a few more sw pieces it will fit right in . and shift when it stops pulling ! no light or tach needed , i never even look at them , just go for it man !
 
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