Reverse rotation 4000rpm tach = cheaper, even for a curved glass backmount. Original facia scanned and photoshopped to 8000rpm normal rotation and then printed on decal paper. A new modern SW tach has the same 270° sweep. Take it all apart and put the new electronic guts into your old housing using the old needle. Not that hard, not very expensive.
Hi: Would you be willing to share your photoshopped (cleaned up) image? I don't have an original to scan and as a computer person, really do appreciate the work that goes into fixing up any image. Heck, I'll even pay for it! Thanks for the great post! Dale
I'm working on an 8BA. I picked up an old 2 piece cap tach drive Chevy dizzy(20$). It'll get turned down to fit the flatty and converted to electronic ignition. I'm pretty sure they never made a tach drive for the flatty but, I love those old Mallorys and it solves a couple problems inexpensively. I like inexpensive solutions. The experts will know but, that's OK. I get the old dizzy look, electronic ignition and a working mechanical tach.
The tach cables for these old SW's are exactly the same as the speedo cables on the old Ford. The "gizmo" I used to hook the tack drive to the front of the flatty in "Bud's B" is actually the front drive and mount from a Chrysler Hemi. It utilizes two of the four holes that you'll need for your stock '32 front motor mounts. Basically it is two standoffs out from those holes, and a stradle strap that holds the angle drive in front of the crank end. The stradle strap is an exact fit Hemi-to-Flathead with just a touch of file work to elongate the holes a hair. The way the ratio of tach verses crank verses distributor speed is adapted is in the angle drive. The distributors run the tach with no ratio adapter, but crank driven tachs use an adapter to halve the ratio and point it 90 degrees to the side at the same time. This adapter is what the Ebay artists seem to think costs a mint, but I bet you could get a similar object brand new. Then build your own mount. PS: this is a very tight fit on a '32. If you have your flatty mounted at stock Ford height, the angle drive will probably JUST fit below the radiator and above the crossmember. The reason I will investigate a generator drive on my next '32 is because I would probably want to use a Model A crossmember, eliminating the space below the radiator.
Hey , thanks alchemy I have a clue on how to make the bracket. Got any pic of the Crysler unit? Or a tip on a source for an angledrive? Of course I'll look at my regular speedshop, eBay. Paul
It is a re-build of an 1940's tach with a rusted away face and rusty bezel. The guts are the same. The only thing not original is the face. Everything else was re-built. Bezel was re-chromed, case polished, insides lubed and calibrated.
No pic (it's tight) but it is basically two four inch standoffs straight out from the bottom holes, and a 3/8" thick strap running across them. The strap has an approximate one inch hole in the middle directly on crank centerline, and the angle drive has a collar on one end that fits into the hole. A setscrew keeps it there. A short square-ended flex shaft (just the shaft, no housing) connects to a square hole in the middle of the Ford crank nut. Drilling that square hole was hard! You don't know how long I had to look for a square drill bit! Actually I just stole the square input from an old Ford (SW) speedo, had it turned down and knurled, and pressed it into a round hole drilled into the bolt. Any instrument shop can make the correct shaft for the crank and the tach if you show them the parts they need to connect to. There's got to be someone in Europe that does SW parts because of all the old military equipment? The angle drive is just a 50% unit. Works fine with my 2:1 tach. If you have a 1:1 tach (uncommon) you will need a 100% unit.
Just a thought. My wife's uncle built a home-grown water injector for his Ford pickup in the mid 70's. He mounted the small water pump on a bracket and the drive wheel was a 1/4" aluminum disc driven off the back - flat side - of the V-belt. Worked pretty good. Looks like getting a speedo drive from a trans and adapting it to the back of the aluminum disc - properly sized diameter wise for the drive ratio desired - would be fairly easy. The aluminum disc could slip a touch, but probably wouldn't as load on it would be minimal. Uncle's pickup didn't seem to have any slippage driving the water injector pump. Increased rpm's raise the V-belt into the drive disc due to centrifugal force so more pressure = less slippage. Interesting part was, the back of the V-belt showed no wear to speak of after several thousand miles. Just a faint line was it.
As for cables, a speedometer shop can usually whip one out while you wait (if not too busy), if you bring them your dizzy and tach.
Here is a source for the 2:1 tach drive that comes with an insert to press into the crank bolt to drive it. Less than $100.00 brand new- http://www.pegasusautoracing.com/productdetails.asp?RecID=254 I am going to build a few of the "hemi" style mounts for myself and will post a drawing with dimensions or can build a few extras if you are not in a hurry.
EXCELLANT! It won't get any better than this guys! If you've got a few inches in front of your crank bolt, this is exactly what you need.
I saw this post pretty late, so sorry if repetitive......I run the SW tach with the sender between the cap and dizzy on the Lazy Eight. The tach is the original one for the car. When the car was parted out the sender left with the motor. I found one on ebay long ago before the craze. I also have an nos sender that hooks up to this style tach that screw into the mechanical tach port on a dizzy. I have never seen one of these other than the one I have. I would take a pic of it but it is not easy to get to......I think the oldest tach I have is a pair! They are for a Chris Craft I believe. I think if you are looking for early tachs, especially tach drive, look into marine or aviation applications.......
has anyone here heard of 'AirGuide' tachometers?i have one..not sure what era,but i'm guessing late fifties,based on the look..
Here's another marine type, with SW gauges, and the tach branded Scripps. I think I dated them about WW2, but did no more because of the problem of driving the tach from a stock 21-stud Flatty - this thread has given me some ideas, so thanks!
Good, that confirms my thoughts on it. Mine is NOS too - I guess the war ended and there was a big shipment of dashes waiting to be installed, with nothing to put them in! Do you know what type of boat they were originally destined for?
Scripps was an engine supplier, like Hercules and Lycoming. They could have gone in anything smaller, like Chris Craft size (which they supplied parts for pre-war)
Not an automotive tach but still a cool Stewart Warner tach from the 40's. This is a Stewart-Warner portable hand tachometer, Model 757-W. Instructions are dated 11/44 and say: "The SW 757-W hand tahometer is an ideal instrument for checking speeds on saws, pulleys, shafts, engines, etc. It can check clockwise or counter-clockwise speeds from 100 to 4000 rpm". It used 2 rubber tips for the shaft. One for shafts with a center hole, the other for measuring the speed of flat shafts, puleys, etc.. This one is on e bay but i remember my grandfather using one like this on the farm when i was a kid too.
Maybe this site is old hat to the gauge guru's but I found it a few months ago and found it interesting reading about the history of S-W. http://www.roadsters.com/sw/
...here is a pic I snagged at the 'Roundup this year of a tach drive off a generator...first one that I have seen in person. --reed
...This has been rolling around in my head for some time now, with the high prices of mechanical tachs these days, I have wanted to take a speedometer and re-screen print the face and use it as a tach...speedos are alot easier to find...for cheap. Do a little research on the ratios needed and where the numbers would lay on the face would be the only real challenge ...then all you have left to do is get a drive off the engine, which to me is the coolest part to make! . just a thought--- reed
An automotive application? No. But I've seen 'em on aircraft. Needles sweeping backwards. The Russians used a 'percent' scale for gauges, including tach, on some Yakovlev (military and acrobatic competition plane mfgr) planes, such as the Yak 50, 18, and such. So, you would see that you were going 95% of redline, or something like that. Engine life on those big radials got pretty short at 105% engine speed. But cool as all hell! And the redline mark is the best! Dumbass questions: where does one obtain decal paper? And, does it fade from UV or stuff like that? Wish I'd kept all my '46-8 Dodge instruments - nice curved glass. Oh well... -bill
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