<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div><br></div>As you figured out, one white goes to “L” on the ignition switch, and the other to the coil +. Based on the overall alignment, I am going to say the left one goes to the switch and the right one to the coil.<div><br></div><div>The blade sticking out in the middle will be the ground to the case, which will be black.</div><div><br></div><div>That leaves the other blade as green to the voltage stabilizer.</div><div><br></div><div>FWIW...<br><div><br id="lineBreakAtBeginningOfMessage"><div>
--<br>Max Heim<br>'66 MGB
</div>
<div><br><blockquote type="cite"><div>On Oct 23, 2024, at 4:19 PM, dave northrup <dave@ranteer.com> wrote:</div><br class="Apple-interchange-newline"><div><meta charset="UTF-8"><div class="WordSection1" style="page: WordSection1; caret-color: rgb(0, 0, 0); font-family: Verdana; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">The wiring diagram shows 4 connections to the back of the tach. I have found nothing which shows which goes to which. I guess I can assume that the diagram is looking at the back of the tach but that’s as much detail as it shows.<o:p></o:p></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div><div><div style="border-width: 1pt medium medium; border-style: solid none none; border-color: rgb(225, 225, 225) currentcolor currentcolor; border-image: none; padding: 3pt 0in 0in;"><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><b>From:</b><span class="Apple-converted-space"> </span>Max Heim <mvheim@sonic.net><span class="Apple-converted-space"> </span><br><b>Sent:</b><span class="Apple-converted-space"> </span>Wednesday, October 23, 2024 6:14 PM<br><b>To:</b><span class="Apple-converted-space"> </span>dave northrup <dave@ranteer.com><br><b>Cc:</b><span class="Apple-converted-space"> </span><mgs@autox.team.net> <mgs@autox.team.net><br><b>Subject:</b><span class="Apple-converted-space"> </span>Re: [Mgs] MGB electric tach<o:p></o:p></div></div></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">As far as I can tell, you have a 3.5” diameter tach from a 1968-up MGB. So you should probably look at the wiring diagram for one of these years. I don't have any personal experience because I deal strictly with pre-68 Bs.<o:p></o:p></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">--<br>Max Heim<br>'66 MGB<span class="Apple-converted-space"> </span><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><br><br><o:p></o:p></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;"><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">On Oct 23, 2024, at 3:25 PM, dave northrup <<a href="mailto:dave@ranteer.com" style="color: blue; text-decoration: underline;">dave@ranteer.com</a>> wrote:<o:p></o:p></div></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div><div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Thank you for taking the time to answer<span class="Apple-converted-space"> </span><o:p></o:p></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">-------- Original message --------<o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">From: Max Heim <<a href="mailto:mvheim@sonic.net" style="color: blue; text-decoration: underline;">mvheim@sonic.net</a>><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Date: 10/23/24 3:23 PM (GMT-06:00)<span class="Apple-converted-space"> </span><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">To:<span class="Apple-converted-space"> </span><a href="mailto:mgs@autox.team.net" style="color: blue; text-decoration: underline;">mgs@autox.team.net</a><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Cc: dave northrup <<a href="mailto:dave@ranteer.com" style="color: blue; text-decoration: underline;">dave@ranteer.com</a>><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Subject: Re: [Mgs] MGB electric tach<span class="Apple-converted-space"> </span><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">What year of MGB is this tach out of? It’s way too small for a Mk. I — is it out of a pillow dash car? It also lacks the inductive loop that would be present on an early car. So this tach is certainly going to be negative earth.<o:p></o:p></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">--<br>Max Heim<br>'66 MGB<span class="Apple-converted-space"> </span><o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><br><br><o:p></o:p></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt;"><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">On Oct 23, 2024, at 12:25 PM, dave northrup <<a href="mailto:dave@ranteer.com" style="color: blue; text-decoration: underline;">dave@ranteer.com</a>> wrote:<o:p></o:p></div></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><o:p> </o:p></div><div><div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Working on an MGA with a swapped in early 5 main MGB engine.<o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"> <o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Trying to figure out how to set up an electric tach. With the car came an MGA tach with the internals swapped for an MGB tach but it doesn’t work. I purchased an MGB tach, and am trying to test it before I attempt to swap the internals for the non working one.<o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"> <o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Here is a picture of the tach; there are 2 white leads, which according to the wiring diagram, one goes to the coil and one to the ignition. Which is which? Or should I just try them? I know that it goes power to tach to coil. We had the car running with the old tach but no movement of the needle before we found out that the gage was bad.<o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"> <o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">Also, I am assuming the extra spade in the tach goes to power? At least the ground spade is obvious as its part of the case.<o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"> <o:p></o:p></div></div><div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">And, while I’m at it, the MGB wiring diagram shows one lead to the gage voltage stabilizer. I’m thinking that can go directly to the fuse box to power?<o:p></o:p></div></div></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;"><20241022_175133.jpg><span style="font-size: 10pt; font-family: Verdana, sans-serif;">_______________________________________________<br><br></span><a href="mailto:Mgs@autox.team.net" style="color: blue; text-decoration: underline;"><span style="font-size: 10pt; font-family: Verdana, sans-serif;">Mgs@autox.team.net</span></a><span style="font-size: 10pt; font-family: Verdana, sans-serif;"><br>Donate:<span class="apple-converted-space"> </span></span><a href="http://www.team.net/donate.html" style="color: blue; text-decoration: underline;"><span style="font-size: 10pt; font-family: Verdana, sans-serif;">http://www.team.net/donate.html</span></a><span style="font-size: 10pt; font-family: Verdana, sans-serif;"><br>Suggested annual donation $12.75<br><br>Archive:<span class="apple-converted-space"> </span></span><a href="http://www.team.net/pipermail/mgs" style="color: blue; text-decoration: underline;"><span style="font-size: 10pt; font-family: Verdana, sans-serif;">http://www.team.net/pipermail/mgs</span></a><span class="apple-converted-space"><span style="font-size: 10pt; font-family: Verdana, sans-serif;"> </span></span><a href="http://autox.team.net/archive" style="color: blue; text-decoration: underline;"><span style="font-size: 10pt; font-family: Verdana, sans-serif;">http://autox.team.net/archive</span></a><span style="font-size: 10pt; font-family: Verdana, sans-serif;"><br><br>Unsubscribe:<span class="apple-converted-space"> </span></span><a href="http://autox.team.net/mailman/options/mgs/mvheim@sonic.net" style="color: blue; text-decoration: underline;"><span style="font-size: 10pt; font-family: Verdana, sans-serif;">http://autox.team.net/mailman/options/mgs/mvheim@sonic.net</span></a></div></div></blockquote></div></div></div></div></div></blockquote></div></div></div></div></blockquote></div><br></div></div></body></html>