Merle Coggins Posted July 4, 2013 Report Share Posted July 4, 2013 A couple of months ago I ordered a 6 volt tach from Westach. They had to build it, so it took a while to get it. Once it arrived I realized that I didn't have a way to mount it, so I ordered a roll bar mount gauge cup from Summit. The gauge cup mount clamps on the steering column and puts the tach in a good viewing area without having to drill any holes in my dash. This morning I finally got it wired up and it works great. It is easy to wire. Just two wires. One to the + side of the coil and one to the - side. Fired up the engine and it reads a nice steady 600 RPM, right about where I usually set my idle speed. So then I had to make a test run. I went over to the east side of town and jumped on I-94, ran that west to the next exit where I got off the highway and came home. These pics didn't come out very well, but it's not easy to hold the iPhone steady with one hand. LADIES AND GENTLEMEN. DON'T TRY THIS AT HOME. I AM A TRAINED PROFESSIONAL UNTRAINED AMATEUR. For those who continue to think their trucks won't go over 45 MPH... Reminder; My drivetrain... Stock, rebuilt 218 CID L6 with .030" overbore. Block and head milled enough to true them up. Fluid Drive with original 4 speed transmission Original axles with '50 Plymouth 3.73:1 gear ratio differential. Yokohama Geolander 235/75R-15 tires that measure 13-11/16" loaded radius (center of axle to the ground), which translates to 27-3/8" diameter If I plug those numbers into a gear ratio calculator I get 2975.82 RPM at 65 MPH, or 3204.73 RPM at 70 MPH My speedo reads a little slow, so my actual speed in these pics would have been closer to 68 and 73, which would come out to 3113.17 and 3342.08 RPM, which is pretty close to what the tach shows. Merle 1 Quote Link to comment Share on other sites More sharing options...
ggdad1951 Posted July 4, 2013 Report Share Posted July 4, 2013 well I've got a 4.3 ratio, so I think I might be correct in my top speed there speed demon! Quote Link to comment Share on other sites More sharing options...
Jim Shepard Posted July 4, 2013 Report Share Posted July 4, 2013 At least for me, the reason my truck won't go over 45 (actually, 50) is the 4:11 rear end. And that's with real tall tires on 16" rims... Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted July 4, 2013 Author Report Share Posted July 4, 2013 But you also have taller tires, Mark. That helps offset my lower numerical gear ratio. Go measure from the center of your axle to the ground and do the math. Then we'll see how far off you really are. I guess Gophers are just slow-pokes. Quote Link to comment Share on other sites More sharing options...
ggdad1951 Posted July 4, 2013 Report Share Posted July 4, 2013 Ed keeps saying he's gonna get use of a tach so we can measure, but it hasn't happened yet. Honestly, on flat ground I bet I could get up to 55mph, but there isn't much gas pedal left at 47mph. Quote Link to comment Share on other sites More sharing options...
Todd B Posted July 4, 2013 Report Share Posted July 4, 2013 I always questioned the low speeds everybody talks about, my first b1b in high school had the original 218 (bored .030). We changed the rear end to something from a car of that era. Original 3 speed on the floor. I would run at 65 all the time, screemed a little, but it never failed me. I had several tickets for speeding and "display of power" with that motor. I actualy told the cop once I did'nt understand, "display of power" it is just a flat head 6, he saw no humor in that. Merle, interesting formula to calculate your speed. I will stick to figuring square feet of wood. Quote Link to comment Share on other sites More sharing options...
Todd B Posted July 4, 2013 Report Share Posted July 4, 2013 Ed keeps saying he's gonna get use of a tach so we can measure, but it hasn't happened yet. Honestly, on flat ground I bet I could get up to 55mph, but there isn't much gas pedal left at 47mph. I just use my GPS to verify how fast I am going. I do agree with Merle, the Gophers/Vikings do have a history of showing up last. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted July 4, 2013 Report Share Posted July 4, 2013 Merle, I like your mounting hardware. Do you have a light in your tach for nitetime driving? Quote Link to comment Share on other sites More sharing options...
ggdad1951 Posted July 4, 2013 Report Share Posted July 4, 2013 I just use my GPS to verify how fast I am going. I do agree with Merle, the Gophers/Vikings do have a history of showing up last. I dunno...the Gopher hockey team seems to not show last....EVER! Quote Link to comment Share on other sites More sharing options...
Young Ed Posted July 4, 2013 Report Share Posted July 4, 2013 Ed keeps saying he's gonna get use of a tach so we can measure, but it hasn't happened yet. Honestly, on flat ground I bet I could get up to 55mph, but there isn't much gas pedal left at 47mph. We gotta work on that now thats the rain has let up. I can borrow a tach/dwell meter and also have a tach like Merles we could wire up. Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted July 4, 2013 Author Report Share Posted July 4, 2013 Don, No backlight for night time driving. They can build them that way if you request it. I did not. Todd, It's an easy calculation. RPM = (MPH x Gear Ratio x 336)/Tire Diameter. But I cheat and use a gear ratio calculator that's part of the Garage Buddy app I have on my phone. Mark, Isn't Minnesota the land of 2 seasons? Winter and 2 months where you can't play Hockey. 1 Quote Link to comment Share on other sites More sharing options...
JBNeal Posted July 4, 2013 Report Share Posted July 4, 2013 I had seen on the Westach site some time back that they offered 6V tachs but had not see a listing in their catalog...do ya pick a style and request it to be 6V and 3500 RPM? Or do they have a limited availability of styles? I had been looking at a 270o sweep, but the style you picked out looks pretty good too. Quote Link to comment Share on other sites More sharing options...
William Davey Posted July 4, 2013 Report Share Posted July 4, 2013 I also have the Westach for 6 volt-positive ground systems. After installing the tach, I converted from standard points to Pertronix solid state ignition and the tack still worked! The Westach tech-rep wasn't sure if it would work, but assured me that no damage would occur so I tried it. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted July 4, 2013 Report Share Posted July 4, 2013 I like that mount and I like that tach. Maybe, just maybe, I'll get the same setup for my '33. For those with trucks with 4.11 rear end ratios: My '33 has its original 4.375 rear end and the mounted diameter of the skinny 17" wheels is very close to that of the later 16-600 tires. I've had my car up to 70 per the GPS and run it at 60 on a regular basis. If you are only able to do 45 then something is wrong. Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted July 4, 2013 Author Report Share Posted July 4, 2013 If you go to their web site and search around you can find 'em. www.westach.com They only show the style I have for 6 volt tachs. They show either the 3500 RPM or 5000 RPM version. I didn't expect to be spinning my engine above 3500 so I opted for that one. I suppose I'm actually running near the top of the scale, so I could have gone with the 5000 version. I ordered it through the web site and the next day I got an email from them that they would have to build one for me as they didn't have it in stock. It would 5 or 6 weeks. I mailed them back that it was OK, I wasn't in a rush for it. It was closer to 7 or 8 weeks by the time I got it, but I'm very pleased with it. Merle Quote Link to comment Share on other sites More sharing options...
P15-D24 Posted July 4, 2013 Report Share Posted July 4, 2013 They also have a 270 degree sweep version which is what I went for in my truck. (Kind of like the old Sun tachs) I used a large PVC end cap for a housing and mounted it to the dash. 1 Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted July 4, 2013 Report Share Posted July 4, 2013 Not a 6 volt but I found this 12 volt tach on the bay a few years back. I looked for a long time to find one that only goes to 6 grand. Quote Link to comment Share on other sites More sharing options...
Jeff Balazs Posted July 4, 2013 Report Share Posted July 4, 2013 Merle; Very nice installation.........reckon I will have to order one for my truck. Thanks for posting this. Jeff Quote Link to comment Share on other sites More sharing options...
Jim Shepard Posted July 5, 2013 Report Share Posted July 5, 2013 I've had my car up to 70 per the GPS and run it at 60 on a regular basis. If you are only able to do 45 then something is wrong. Let me clarify... I suppose my B2B would go faster than 50mph (and I verified this with my GPS), but at that speed it sounded like it was going to blow up. I guess I "chicken'd out..." Quote Link to comment Share on other sites More sharing options...
Desotodav Posted July 5, 2013 Report Share Posted July 5, 2013 I was reading a post on the car side about digital retro dashes and thought that I'd do some searching to see what's out there for our trucks. I came across the Dakota Digital site... http://www.dakotadigital.com/index.cfm ... and boy don't they do some interesting stuff! I wonder how a fella would go mounting one of their Jeep or Bronco dashes (see attached) in a truck like ours? Pity that I'm such a stickler for originality in my truck/s !!! Quote Link to comment Share on other sites More sharing options...
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