External VR installation

[Driver_X]

'74 with external VR. I've been chasing tach bouncing and I've pretty much narrowed it down to VR. I've tried both that I have, one I bought used and the one on the car. One will have a range from 13.3.13.5v and the other 13.8-14.4v. I've looked here and the one that our sells is different from what I have.

Here is the 13.8-14.4 VR:



While this is what is availble from Pelican:



Since this not a stock look and I don't want to wait a week if I don't have to. Does anyone have any other suggestions that I can get locally (Napa, Autozone, Pep Boys etc) that they have used sucessfully? Post a pic if you have please, I'm curious as to how you have connected it.

[Joe Bob]

A VR is a VR. The local parts stores should have something that works. Not many are sold anymore as most people upgrade the alt to one with an internal VR.

[Walter_Middie]

I'm guessing that the old one is mechanical with contacts that vibrate open and closed to regulate the voltage, whereas the new one is all electrical. If it were me, I'd take the old one apart and try cleaning the contacts. If that didn't work, I'd mount the new electrical gizmo inside the case of the old one so that you have modern electrics with the look of the original.

[Driver_X]

Took apart the old (black casing) one and everything in there looked pretty darn clean. By contacts do you mean the second photo? I pried them apart a bit and they also look clean.

[Joe Bob]

Re reading.....14.4 isn't particularly high a reading. What leaves you believe the VR is bad and/or the tach issue.

[Driver_X]

Tach bounces all over the place. Reading the forum the VR seems to be the leading culprit. I've already checked connections at the dist, cleaned grounds etc.

Now for the first 10 minutes of driving, the tach is rock solid, once oil temps starts to move up, around 130 degrees on the gauge, the tach will start to bounce a bit and get worse from there.

Driving on the highway, it'll bounce from 3-4,000, down to 2,700 up to 3,500. You get the idea. Once in a while it'll settle down for 30 seconds and then off it goes again. It's annoying :-)

I'm open to other suggestions but I was thinking that a known new working VR would be the way to eliminate any other problems, and it seems the most popular reason for bouncing tach.

I should probably add that the car came with an MSD w/ MSD coil installed by the PO.

[Walter_Middie]

Points are usually the first thing to check with a bouncing tach. Most newer cars don't have points, and the suggestion is usually voltage regulator - but in your case, I'd say points first. Clean yours up and set the dwell - if that's it, maybe it's time for a new set of points - maybe it's time for a new set of points anyway - or switch to Pertronix and never have to think about it again.

Before I switched to Pertronix, I'd set my dwell by pulling out the distributor, mounting it in the vise, and spinning it with a drill. Setting the points dwell was really easy. No big fingers trying to reach down into a small space when the distributor was still in the car.

[Driver_X]

Checked the dwell couple of weeks ago, solid 35 on the meter. Didn't actually physically look at them though....would a tit on the points have this effect without affecting the dwell?

[Walter_Middie]

Clean up the points and tell us if that solved the tach issue.

[Driver_X]

I'll do that tomorrow and report back...thanks!

[Driver_X]

OK, finally got around to putting in a new set of points today. The old set had a bit of a tit on them. Bouncing tach issue is gone....many thanks guys!