I recently attempted to change out the clutch on my bug for the first time. All went well right up until I tried to start it. The starter kicks over, all the electrical works, but for some reason she’s not firing. Upon removing the spark plug i found out there is no spark. The plug cables and plugs themselves are brand new, so I’m guessing that’s not it.
The best thing is to go back and check your work. Check every wire you took apart or touched. Check the fuses. Stuff that happens after fixing something has got to be 95% of the time something inadvertently done along the way.
First thing is to make sure the fuse holder for the ignition fuse is not still disconnected or the fuse blown. This holder should be located near the generator on the sheet metal fan shroud near the carburetor. It’s a linear black widget and from a hazy memory it has to be disconnected when pulling the engine.
I’m not sure if a 72 had points or not. My 67 Beetle was very sensitive to the condition and gap setting of the points. The OEM Bosch points worked best for me. Also check the Ballast resistor or wire coming off the distributor.
To get spark you need 12 volts to the + terminal on the coil, and some method or another to ground the negative terminal coil, which I presume to be points or a contraption inside the distributor which mimics points. Here’s what I’d do
Make sure you have 12 volts at the correct terminal of the coil
Make sure the - terminal of the coil is connected where it should be
Remove the dizzy’s cap and make sure the ignition rotor is properly seated on the shaft
While you have the dizzy cap off, make sure the number one cylinder is at top dead center on the compression stroke when the ignition rotor it pointing to the number one cylinder. Note that there are two top dead centers, one on the compression stroke, one on the exhaust stroke. In removing the distributor you may have these mixed up now. You should still see a spark though. But maybe there is a spark and you aren’t seeing it for some reason, but he spark is occurring on the exhaust stroke. It’s hard to start the engine if the spark occurs on the exhaust stroke.
While the dizzy cap is off, double check that the points are opening and closing and have the correct gap, or if an electronic module is installed, that the sensor is properly aligned and gapped with the little thing that spins around. If nothing seems to be turning like it should in there, it’s possible the dizzy gear isn’t properly mated with the engine gear that turns it. In that case, try removing then re-installing the dizzy. Like a dizzy re-boot.
Edit: Check the condenser is correctly installed and connected, if you have one.
As I recall the VW air cooled engine distributor was driven off the oil pump with an off set slot and could only be re-installed with the rotor in time. Of course the distributor can be turned more than 60* so it can be out of time too far to run but a “dizzy re-boot” wouldn’t be necessary.
I still think there’s a black single wire dangling loose that provides power to the coil. It’s pretty common for those to fall out of the way and get overlooked when the engine is reinstalled.
Told the story before but I was changing the points on my 59 Bug and it wouldn’t start. Finally had a mechanic friend of my Dads come look at it. On the wire attached to the dizzy (distributor), I had reversed the insulating washer so that it was grounding out. Changing the washer around to the other side of the wire connector did the trick. Gotta check your work.