Mechanical Tachs

B

Brian King

Member
Hello all. I’ve got an old mechanical SW tach that I’m not sure if it’s any good. I’m thinking about going through it myself- any suggestions/tips? Thanks
 
You have the drive? or the tach. Lots of old tachs around, the drive is the hard part to find
 
As to working on the tach head itself, I'd send it out to one of the speedometer guys to repair. I think it's full of springs and wheels, so be careful when disassembling if.

I found a NOS SW 5K mechanical tach. Luckily, I have an 8BA, so I found an SBC Mallory "flattop" distributor on eBay with an integral tach drive. I'm going to have "Charlie NY" convert it for flathead use. Then all it will take is the proper cable. (I think a readily available Corvette unit will work).
 
The end of a Ford speedometer cable may fit the tach. If so, you can turn the tach with a drill to see if it has problems.
 
The SW 674L tach drive is the best one to use when driving a mechanical tach. The ones with 90 degree mounting brackets are impossible to use,..... as the small flex cable driving the tach drive gearbox will work harden....and quit. The "direct drive" 674L is the best unit to use. I have sold 80 units over the last 12 years, and I still have a few from my last batch.
 
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tubman said:
As to working on the tach head itself, I'd send it out to one of the speedometer guys to repair. I think it's full of springs and wheels, so be careful when disassembling if.

I found a NOS SW 5K mechanical tach. Luckily, I have an 8BA, so I found an SBC Mallory "flattop" distributor on eBay with an integral tach drive. I'm going to have "Charlie NY" convert it for flathead use. Then all it will take is the proper cable. (I think a readily available Corvette unit will work).
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The Corvette tach drive will work in a 8ba. You just have to have it modified for a flathead. Like Tubman, I use a Chevy Mallory flattop YZ with mechanical advance.
 
I used John Bordas in Texas for my Harley speedometer, he's a straight shooter and did a great job, very reasonable. I don't know if he does tachs. Give him a shout.
j.bordas@att.net
 
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