ctuinstra

On my '68 coupe, the ammeter tends to flicker a lot. At idle it will flicker between 0 and something higher. During periods of driving it will settle down and seem to fairly stable and then flicker again.

I started looking into it a bit and then realized I have a very old system with the external regulator (the one with two relays in it). This is the system I believe before the 10SI. I measured a very jumpy 5-6 volts on one of the two terminals and a very steady 8 volts on the other. The output of the alternator, generator or whatever you want to call it, seems to be very healthy. I don't have any problems with dead batteries or the like.

I'd like to know:

1) Is this normal for a twitchy ammeter with this setup?
2) How difficult is it to change over to a 10SI setup with an internal regulator?

MelWff

conversion kits, check your connections at alternator and battery including ground and starter

http://www.americanautowire.com/cata...ersionKits.pdf

7T1vette

Unless you want to keep your car exactly as the factory built it, you might want to 'ditch' that voltage regulator and swap that early-design alternator for one with a built-in regulator (the next time the alt. needs to be replaced). You may need to run an extra wire for that upgraded alternator; but you can figure all that out in the meantime.

hugie82

Check the contacts in the external regulator. You have a low voltage side and about 2000 rpm the high voltage side kicks in.
My high side went and when ever I was on the highway, my battery would go dead but around town it charged fine. You're probably the opposit...

ctuinstra

Thanks for all of the replies guy! I have a decision to make whether I want to spend money on the VR or just replace the system. I would like to up the output of the alternator since I have an electric fan. I may clean the contacts of the VR to see if that helps for now. I also noticed the block ground cable is bathed in oil and road grime. I'm sure it wouldn't hurt to take that off and clean everything up for a better ground.

ctuinstra

One more question, will the newer "SI" or "CS" units physically bolt right up or are the mountings different?

DUB

I can not tell you on how many electrical issue I have to repair that the condition of the terminals often times has everything to do with a problem. They are either corroded/dirty or loose to the point that the terminal can fall of easily due to excessive heat and arcing due to being loose and it can not handle what amps that need to pass through it correctly.

I agree with the upgrade also. Adding aftermarket electrical components on a system that may be sub-standard and not able to handle the added output...many people do not take that into account.

DUB

ctuinstra

I took the VR off tonight and opened it up to see what I could see. Either this thing has been replaced at one point or it held up quite well over the last 45 years. It looked like new inside. I inspected the contacts with a magnifying lens and they look really good. I cleaned the terminals with sandpaper and the contacts with 400 grit sandpaper. I check the resistance of the wire-wounds and the 16ohm was good and the 14 ohm was around 9 ohms.

I reinstalled it and now the ammeter flickers so fast that it's just a blur.

ctuinstra

Cleaning the contacts on the relays of the VR caused the gap to change slightly. This effected the adjustment of the VR. It didn't take long to notice the output of the alternator is up to 15.8 volts! I adjusted the spring on the VR and brought the voltage back down. Now the ammeter is pretty settled down until you put a load on. The more I read about the old style VR is that the one coil is referred to as a "vibrating point" - key word here is "vibrating". I suspect this normal operation of an old mechanical VR. For $21, I'm going to try the solid state VR to see if that smooths it out until I decide what to do about the alternator upgrade.

7T1vette

A solid-state V/R would be a good option until the alt gets changed.

ctuinstra

I purchased the solid state version today. Oddly it's the cheap China brand. It weighed in around 4oz.

They had a lifetime warranty version that was almost identical to the OE other than the cover was gray. I opened it up and it's the same two relay type.

Plugged in the cheap China brand and low and behold, the flickering is gone! The output of the alternator is good. Sure your still going to get a little flick of the needle every time you tap the brakes or turn on the headlights, that's normal.

So I believe it's normal for the old style to have a bit of flickering to it.