GMC tachometer

NOS tach, manufactured by GM in Flint, Michigan. Some paint wear on bezel, 3 3/8 dia. body with 5/8 18 thread for drive coupling. Not sure what it is out of, or when. $25 plus shipping.

Perry

[Bob Carriere]

HI Perry

Would love to instal one in my CMP with the 261.....but... how do you connect to the engine...???Does anybody knows>>

On some large 361 Dodge truck it was driven by a gear drive attached at the distributor..... on my MF farm tractor it is driven form the back of the camshaft.... which leads me to beleive they are driven one to one.

Every electrical RPM gauge I have seen are scaled for 7 or 8 Thou revs which is not what I am looking for....... 4000 max would be ideal.

any suggestion anyone????

BooB

[Phil Waterman]

I think Mallory had a hot rod distributor unit with a tack drive. Take a look through some of the old hot rod chevy sites. I wonder if the application that this tack came from is the DUKW which would solve the drive issue.

[cletrac (RIP)]

I'm pretty sure that some of the bigger old Chev trucks had tach drives on the distributer. Having said that, finding one might be pretty hard, but anything's possible. Bob, I'm pretty sure your ear should be able to tell when the old 261 is getting wound up, especially with it under your left armpit.

[Hanno Spoelstra]

Originally posted by pkitson
Not sure what it is out of, or when.

Maurice Donckers, a knowledgeable friend of mine, says it's from a Stuart Light Tank.

H.

Good morning gentlemen,
the tach is military, not sure what it is out of. Truck applications would probably be driven as has already been mentioned, most likely off the distributor or in some cases off the cam. If this is out of a radial engined Stuart, I would guess the cable drive was from the input shaft on the transmission up by the driver, the same set up the Shermans used. On the twin V8 Stuarts, I would think we would be back to drives off the distributors.

Perry

[tankbarrell]

Originally posted by Hanno Spoelstra
Maurice Donckers, a knowledgeable friend of mine, says it's from a Stuart Light Tank.

H.

Or a Chaffee. But yes, an M5 Stuart with the twin Cadillacs.

Adrian

[tankbarrell]

Actually, given the location, I suspect it is from an M4A2.

[Grant Bowker]

When I bought my C15A, it was missing some parts and came with extras of some. In addition there was a tachometer in a jar. I have no idea what the tachometer came from, but it was marked on the back that the guage reads twice cable speed so it must be driven from the camshaft or distributor of whatever the application is. Also printed on the back is a statement that the hour meter is based on 2450RPM (may not be precise, working from memory) in other words it is a revolution totalizer, at idle it will record far less than true hours and if you drive around flat out all the time it might record more than true time.

Can anyone identify what it is used for from the part numbers on the dial?

[rob love]

I don't know about the application, but I would worry about the exposure to the radium from that opened case.

[Grant Bowker]

E-bay listing http://cgi.ebay.com/ebaymotors/Vinta...QQcmdZViewItem is for a S.W. 503-B, but instead of being identified as part number 7727466 it has MS 35916-1 and according to the seller is for aircraft use. Clearly Stewart Warner sold the same instrument for several uses.

http://mpbundels.mindef.nl/overig/Bark1009/6350_tot.htm has a listing for MS 35916-1 (&2) under NSN 6680-00-514-4090 and 6680-00-825-2076 for NIKE and HAWK (sounds like support equipment for missile systems?????) and lists the tachometer as containing 92.5 kBq of Ra226.

Searching on the NSN 6680-00-825-2076 produced several results, one of which, http://www.clarktruck.com/parts.cfm lists the tachometer as being used on M35 trucks. Clark Trucks is a "business that specializes in US Military 6x6 all-wheel drive trucks". Another of the results http://mipcorporation.com/database/mipdatabase.shtml gives a MSRP of USDollars 268.45 for the tachometer.

For Bob Carriere, Alex Blair and I noticed yesterday in the Chev Major Assemblies Manual that some engine assemblies are shown as coming with mechanical tachometer drives. I don't know what the application was but clearly some CMPs had a 216CID engine with mechanical tachometer.

I downloaded the Stewart Warner catalogue today, most interesing, a wondrous assortment of electric and mechanical tachometers as well as may other instruments, again electric and mechanical. Also tools and materials so that you can make your own speedometer and tachometer cables.

[Bob Carriere]

So tachometer seem to be about $10 to $25 on Ebay so they are plentiful..... and all low rpm models with a max or 4 to 5K....

The problem is "finding" the distributor drive........ that allows the cable to be connected........ surely some of the GM dizzy for the 261 must exist somewhere........ I know where I can find NOS governor for the Chev 6..... and I am positive that tach were installed in some commercial application..... btu where???

It would be a lot easier to install an electrical tach.... but everyting I have seen is for 7 or 8000 rpm and not suitable for a slow truning 6 cyl engine.

Grant in your SW catalogue.... do they list a 4 or 5000 rpm guage?

Bob

[Grant Bowker]

Most of the tachs for gas start as 0-6000RPM, they do list "diesel" applications, including some that take their signal from the alternator, don't ask me how, that are 0-3500RPM. I downloaded the catalog from http://www.autoelectricservice.net/gauges.html