Stewart Warner tach drive

Henry_steel_32

Junior Member
Hello all! This is a strange place for my first post on the forum but I am looking for a Stewart Warner tach drive that gets driven off the fron the crank. I have had no luck finding one on the usual auction sites. If anyone here knows where to source one that would be greatly appreciated. I need it to drive my curved glass Stewart Warner tach for my 32.



Thanks in Advance!
 
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Like this one.It’s complete including the crankshaft bolt out.
 

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Like this.
 

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The 674L drives were reproduced not long ago. The fellow who reproduced the drive ( whygoby ) is currently out but you can contact him and get on his list. They are nice since they do not need a bracket.
 
I can vouch for what Terry, OH said - I know 'WhyGoBy' (Doug Clem) and his reproduced parts are excellent. Also, he's a really good guy in general, so reach out to him.
 
I reached out to Whygoby a few weeks ago and had a pleasant conversation with him regarding the reproductions. He is still looking for a machine shop willing to do the work and doesn’t have an estimate when that will happen… if ever. I need one as soon as possible so that is the reason for my reaching out here. Looks like flatheadrunners might have what I need so we’ll see what happens.

Thanks
 
Any speedometer shop should be able to furnish just about anything associated with cable drive tachs. Almost all big trucks on the road have a cable drive tach.
 
I wonder what ratio the resulting SW drive used - and what model number was used for a generator mounted setup (gears inside of it)? Obviously, the generator pulley is a smaller diameter than the crankshaft pulley - so the same SW crank mounted unit would not provide the same RPM if just swapped to the generator. (would show a higher number)

To summarize: the SW drive unit that you'd use for a crankshaft mounted tach drive would NOT work for the above generator mounted tach drive - the drive ratios would have to be different for the generator version . . . or the tach itself would have to be different, or both.
 
Over the years I have seen several different configurations of the S&W tach drive and the last time I checked about 3 years ago many of them were still available.
There was direct drive in both right and left hand rotation for crank nose application and what was called the .500 which was a half speed input for cam nose drive applications, both right and left rotation. There were floaters and fixed mounts.
One disadvantage of the float mount was, if the cable or the drive froze up it broke the cable and sometimes the cable got the fan and radiator in the process.

Here's a pic of a home made fixed mount on a model B engine and a pic of a right angle cam drive on a flathead V8 both driving Jones Motrola chronometric tachs which are far more accurate than magnetic drive tachs.
 

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