Revs go up, lights go down Revs go down lights go up

So, as title says really, running great but revs are dropping and raising very slightly and light are dipping then going bright, not high beam that still works either way. It's not just when on idle I can see the lights doing it when driving at speed.

Coil, Plugs, points, condenser, cap, leads are all new

Just wondering if somone could point me the right way with where to start with this one.
I have cleaned the fuse terminals and cleaned and replaced the fuses so far

Thanks

 

Agh yes forgot to say 72 van type 1 1600cc with an alternator

Ta

 

They told me that's how you make your van faster

 

That wouldn't be so bad though(apart from cost) if it is that, I have just fitted an alternator to the beetle so I know how that all goes

 

Ill give them a little clean up again, they shouldn't be to bad though

 

Been messing with it this morning, I think the battery is hissing a bit when I turn the van off, could be somthing with that

 

Hissing battery can suggest overcharging, again faulty regulator/alternator.

 

^^^ WHS - Hissing battery may be venting hydrogen, due to overcharging. Wait for it to stop and vent the area before doing anything as there is a risk of explosion if there's a spark/flame.

Measure the battery voltage with engine off, engine idling ("dim" lights) and engine idling ("bright" lights).
Should be about 12V (between 12.0 to 12.7V) engine off and between 12 and 14.4V idling. The battery will gas above approx 14.4V.

It sounds like your alternator's voltage regulator might have failed. These can be internal or external, and if internal you may have to remove the alternator to get to it (depends on type).

 

It is looking very much like it is this doesn't it, i have a volt meter so will do those checks, the alternator regulator seems to be an internal one, are any of these parts replaceable or is it a whole new one?

Thanks for helping

 

Voltage regulator should be replaceable, but I think there's two types of alternator for a 1600. One has a removable plate with the regulator attached, which you can change with the alternator in the vehicle. The other type requires removal as it's "mounted behind the front cover of the alternator nearest fan, NOT under the black plastic cover with the spade terminal like earlier types."

Might be worth a read of this thread, as it describes both and there's some pictures of the second type:
http://thelatebay.com/index.php?threads/battery-sulphur-eggy-smell.32469/

Once you've got it sorted, check the electrolyte level in the battery (if it's not a maintenance free one) and top up with distilled water if needed. If you've caught it early enough (no bad smell yet) - the battery will probably be ok.

 

Thanks @MarcT512

I have Just found the later internal regulator in Gsf/VeeWee £31, so not to bad if i can narrow it down to this.
I cannot see any brushes listed for it yet though, if i need them, are they in with the regulator maybe, when i did the one on my beetle i think i remember them popping out when i took the cover off?

Thanks

 

Depending on alternator type the brushes may be attached to the regulator or seperate
You need to remove the plate on top of the alternator and take a look
Is it a recently new alternator?