Summershandy Posted July 16, 2019 Share Posted July 16, 2019 Check out this neat unit I found at a garage sale cheap cheap. Original sticker price $219.95. I also picked up a timing gun. Both are in mint shape. Came from an old retired mechanic. I've since used the gun but I noticed this is only for 12 and 24 volt systems. Will I be able to get a correct RPM setting from this unit still even though I've got a 6 volt system? I would typically go by ear but my setting is 365 - 385 so it's pretty low and I'm unsure what that really sounds like. Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 16, 2019 Share Posted July 16, 2019 How is the unit powered? If it's reading RPM through an inductive lead on a spark plug wire, I see no reason why it wouldn't work on 6V as well. If it uses the battery to power the whole unit, however, it might not work although you could hook it up to a 12V battery and perhaps still use it to test the 6V car. If it plugs into 110 wall outlet, then you should have no problems at all beyond the fact that the spark might not be powerful enough to trigger an inductive reading through modern spark plug wires. I used to work for an automotive diagnostic tool manufacturer (Actron) and one day they asked me to bring in my father's 1925 Buick so they could see if their various tools would work on 6 volts. Most of the timing lights had no problem with 6V, one of the tachometers worked, and several others that the engineers figured would never work actually did, although you probably don't need an O2 sensor tester on a 6V car. They just tested everything. The funny thing was that they didn't seem to really know what would work, they had to find out by hands-on testing. The other cool thing was that they had a dyno test cell and I got to put the '25 Buick on the dyno. A ripping 41 horsepower at the rear wheels at 3000 RPM! I'm sure I still have the charts somewhere. So hook it up and find out--you probably can't hurt it. Link to comment Share on other sites More sharing options...
Summershandy Posted July 16, 2019 Author Share Posted July 16, 2019 12 minutes ago, Matt Harwood said: If it's reading RPM through an inductive lead on a spark plug wire It hooks up to the 6 volt battery for power and a lead goes to the coil. The timing light worked as my timing was bang on. Link to comment Share on other sites More sharing options...
Matt Harwood Posted July 16, 2019 Share Posted July 16, 2019 I'd hook the unit up to a 12V battery for power and then do the testing on your 6V car. All it's doing is looking for a spark, it doesn't know if it's 6V or 12V. Link to comment Share on other sites More sharing options...
PFitz Posted July 16, 2019 Share Posted July 16, 2019 (edited) Nice finds. I have a similar multi-meter that uses 12 volt power, but I only work on 6 volt cars. As Matt said, it'll work off any 12 volt supply and all the meter test readings for 6 volt are then fine. Reads voltage, ohms, dwell, spark KV, generator output & starter amps draw, engine speed - mostly with inductive pickups, so voltage of what your testing doesn't matter to it. I use a 6/12 volt battery charger set to 12 volts when in the shop. When I want to go for a road test, I use a bunch of flash light batteries in a rolled up paper tube with rubber bands to hold it all together. There's a storage compartment in the back for all the test cables. I put the paper roll "battery pack" in there. Then I can place the meter on the front passenger seat and check readings as I drive. My 1970's Sears Craftsman timing light doesn't care if it's powered by 6 or 12volts, the strobe light is just as bright. BTW, you can use timing lights not just for timing, but for what I call a poorman's oscilloscope. Clip the inductive pickup on at each spark plug wire in turn and watch the flashes. Each flash timing should be an even rhythm. If it skips a flash you have a misfire with the wire/plug. If you see some wires have double flashes, then there are shorts in the cap or from another wire, or inductive cross firing from wires being close in the wire loom. Paul Edited July 16, 2019 by PFitz (see edit history) Link to comment Share on other sites More sharing options...
Rusty_OToole Posted July 16, 2019 Share Posted July 16, 2019 Last week I bought a lithium ion booster battery. It's about 7 x 3 x 1 1/2 inches and weighs between 1 and 2 pounds. It would be great for powering 12 volt diagnostic tools to use on a 6 volt car. It has USB ports on it for charging cell phones, lap tops etc. And of course, it will jump start your car too. Link to comment Share on other sites More sharing options...
Summershandy Posted July 16, 2019 Author Share Posted July 16, 2019 1 hour ago, PFitz said: I use a 6/12 volt battery charger set to 12 volts when in the shop. I was going to ask as I do not have a spare 12 volt battery kicking around. I remember in shops I built an 8 track stereo wooden cabinet that ran off a battery charger. Guess dad knew that worked. I thought that was a neat idea! Link to comment Share on other sites More sharing options...
PFitz Posted July 16, 2019 Share Posted July 16, 2019 (edited) 1 hour ago, Rusty_OToole said: Last week I bought a lithium ion booster battery. It's about 7 x 3 x 1 1/2 inches and weighs between 1 and 2 pounds. It would be great for powering 12 volt diagnostic tools to use on a 6 volt car. It has USB ports on it for charging cell phones, lap tops etc. And of course, it will jump start your car too. Not to highjack the thread, but a bit of a warning. I had one of those emergency Lithium Ion booster/charging kits. A present from the Stepson last Christmas. Last seen it was out on his front lawn smoking away where I threw it to get it out of the garage. We tried to use it to boost start his 6 volt 1926 touring. The red light on it started flashing and it got so hot it started smoking. And, it kept blinking and smoking for about ten minutes. Nothing in the directions about not using it for 6 volt starter use, but I suspect it is only happy with 12 volts. No harm to the car, but I felt real bad for the Stepson. Paul Edited July 16, 2019 by PFitz (see edit history) Link to comment Share on other sites More sharing options...
PFitz Posted July 16, 2019 Share Posted July 16, 2019 1 hour ago, Summershandy said: I was going to ask as I do not have a spare 12 volt battery kicking around. I remember in shops I built an 8 track stereo wooden cabinet that ran off a battery charger. Guess dad knew that worked. I thought that was a neat idea! Works fine. Just make sure the clip-on leads don't touch each other, or the ground, while your busy working on the car. Paul Link to comment Share on other sites More sharing options...
Grimy Posted July 16, 2019 Share Posted July 16, 2019 I use a 7mah sealed 12V battery, most frequently used as backup for home alarm systems, gate openers, and for Uninterruptible Power Supplies (UPS), to power an old GPS that's easily moved from car to car, AND to power 12V test equipment. A Duracell brand, longest-lived, was $37 at Batteries Plus, but I've also bought them at Tractor Supply (house brand). Small, non-spill (sealed) features make it indispensable. Link to comment Share on other sites More sharing options...
Summershandy Posted July 17, 2019 Author Share Posted July 17, 2019 Well, strangely enough I couldn't get the unit to work off a 12 volt battery charger. So for fun I hooked it up to the existing 6 volt battery. Seems to have enough juice to run it. I set the idle and it was around where I thought it should be anyway just under 400 RPM's. Link to comment Share on other sites More sharing options...
Bloo Posted July 17, 2019 Share Posted July 17, 2019 Most battery chargers are unfiltered, meaning the power is not clean enough DC to use unless a battery is connected. Try a 12v battery. 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now