Yet another Voltage Regulator q

[Bob T]

Howdy, Recently I replaced the old fried points distrubuter in my 318 with an electronic one and wired in a relay for starting, runs sweet no problem there.
Around the same time I replaced the old candlepower headlights with H4 new gen type that are a higher output BUT draw the same current as the old 60w ones, they also work fine.

The recent problem is having the voltage flare up to as high as 16.2v when the revs get up, at idle it is stable around 13v or so. I first noticed it when the  lights started flareing on the way back from a run.
I thought it was the V.reg and got a local replacement similar type and fitted it. It runs fine at idle but as soon as the revs go up a bit ( even at fast idle )  over 12.85v it drops out with no output and the voltage flares up again. So I thought , damn faulty unit and got another one off the supplier. exact Same thing happens with this one .
When I disconnect it out of circut with spade terminal off , the battery voltage goes to around 12.5v and stays there stable when I rev it up. What will result be if I leave v.reg out of circut?

Any ideas guys?? Thanks

[Nacho-RT74]

what alt and whats the iddle on your car ?

[Bob T]

Alt would probably be the factory stock one , no tags on housing , Idle is around 750

[C500]

Any ideas from here Nacho??? 

[Nacho-RT74]

I think it could be some internal part shorted at alt.

what gets me surprised is the suposelly regular "output at iddle". 750 RPMs doesn't give enough juice to feed everything on car but just the ignition system. Stock alts are normally not able to get 13 volts at iddle. EVEN LESS with the pulley I can see there, what it looks to be the big one.

do you have a working ammeter ?

( sorry it took so long, I simply forgot to check )

[Bob T]

I think it could be some internal part shorted at alt.

what gets me surprised is the suposelly regular "output at iddle". 750 RPMs doesn't give enough juice to feed everything on car but just the ignition system. Stock alts are normally not able to get 13 volts at iddle. EVEN LESS with the pulley I can see there, what it looks to be the big one.

do you have a working ammeter ?

( sorry it took so long, I simply forgot to check )

No problem, Ok , we now have about 12.1V at idle, no working ammeter as that section of wiring in the dash is burned out and I will replace over the winter, ammeter posts were cooked up, so no fuel, oil pressure, temp, ( but has seperate temp guage installed) or alt guage working - but that is the side issue that I know how to fix compared to the main problem of over voltage /surges.

I have changed out my existing alternator and voltage regulator with one that was working fine in a friends 360 truck and replaced the main earth to the block and earth strap from firewall to back of the block, has 2-3 ohms resistance from there to neg battery post and stil the surges continue.
\A few months ago I changed the faulty points distrubuter with an electronic one procomp brand, which required the resistor to be removed and relay fitted 12v on 85, ground on 86. battery + on 30 n/o contact and other side of contact 87 to new coil +. and everything appeared to run fine until just recently.
Any help much appreciated Nacho  , otherwise I will be taking it to the local autoelectrician  next week.

Thanks , Bob.