Engine Startup Rig Wiring Questions (Page 1 of 2)

Very cool Nick!

(I know nothing about electrics but does a voltage regulator fit in there?)

looks very good. when we break in engines on the stand i don't worry about the charging system, the engine will run for a long time on a strong battery. i use a mechanical oil pressure gauge. but your setup is worthy and the way you have illustrated the schematic it shows a good grasp of what you're doing.

an internally regulated alternator has two terminals that are separate from one another, one is a 6mm threaded stud and one is a male spade. the image in your schematic is this type. all new alternators that you can buy are this type. the original alternators that came factory on bugs in the 70's used an external regulator and have a three male prongs on the top of the unit.

scott lyons
germansupply.com

For this schematic to work with an external regulator would I have to tap the D+ after the regulator (somewhere?) rather than right on the alternator?   Or is the regulator its own closed circuit, and I could tap D+ from the alternator regardless of the regulator?

I'll add in an optional regulator section if it'd require a different wiring.

On a somewhat related note: if the car has a regulator inside (three pronged wire coming through the firewall) is anything connected to the voltage regulator inside the car?  (why is it inside the car in the first place?)

Last edited by thebignic (2010-02-09 09:50:50)

The 6 volts bugs had VR on the gen. In 67 when they went to 12 V they put it under the backseat and continued that way when they went to Alt in 73? .
All that is hooked to VR is wiring to Alt and up to idiot light which is needed for alt to work (gets excited by that voltage)
Nice job you are trying to do.
I have started them on the floor using a trans, battery and starter button. Remove the oil switch and crank till you have oil coming out and then fire it up. Works OK that way too

Well I could be naive in thinking that the engine should be balanced enough not to flip over or anything.  If it's revving very very slowly, perhaps it might want to rock a little bit.

I'm not sure if I'll place it directly on the floor, or leave it on the engine dolly. Since the 'footprint' is much wider if I just leave it on the dolly, I think it will have better balance, but it'll also have wheels and it might want to move/vibrate around a little...  I think if I rested it on the floor, directly on the oil strainer cover, it might want to rock over if I revved it too much? (or was careless, etc) but I'll let someone with the voice of wisdom attest to the feasibility of such an endeavor

I'm going to do it anyway (likely on the dolly), but I wouldn't want to suggest anyone else do it before I try it...  I will report back

That said... at the end of the BugMe video, they start up their engine directly on the floor and it seems just fine.

I'm with Burr; make a test stand. The vibrations of a running engine sitting on concrete would make me uncomfortable with a split case design.

Also, is the primary starter supply lead in VW's connected through the switch? Most other vehicles have the positive battery lead connected directly to the starter, a momentary switched positive connection to the solenoid, and then the power is applied to the starter motor when the solenoid contacts close.

Paul

That would work as long as you didn't block airflow under the cylinders. I guess carpet would work too... as long as it didn't get too hot, lol.