Bug Update: Just in Time

One of the most frustrating aspects of working on my old Beetle now was one of its biggest selling points back in the day: interchangeability.

The engines in Volkswagen are just as interchangeable, and that's my problem. Over the years Volkswagen made a lot of different motors for the Bug, and almost all of them will fit in my engine bay. It's strange to think of now, but at one time Beetles were so plentiful and so cheap to work on that motors were simply replaced when something major went wrong. Instead of fixing your problem, you'd go to the junkyard, find any working VW motor, unscrew four bolts, and you'd be all set. Of course it's a little more complicated than that, but you get the idea. 

I wanted to set the ignition timing on my motor, but I didn't know if it's a 1200, a 1300, a 1500, or a 1600? Most repair books point you to the serial number that's stamped on the crankcase (right below the generator stand). This number will tell you when the engine was manufactured, and then you'd have a good chance of identifying the motor. Here's my number.

Surprisingly, "D023360XR" isn't in any of the repair books. For years I scoured libraries and bookstores, but I couldn't find any VW book with that series of letters and numbers. My dad couldn't either. I have the repair book he left behind, and from his notes I can see he was also stumped. But that was before the internet and VW forums.

What we didn't know is that in the late 60's Volkswagen had an engine replacement program. If you blew up your motor and took the car to a dealership, you could get a genuine Volkswagen replacement engine with (I presume) a warranty. The factory would mill off the original serial number and stamp the VW Recycle logo and a new number on your "new" motor. 

Looks like my exchange motor was installed sometime after October 1968, buy that doesn't mean my engine was made then. According to the above information, I'd know for sure that it is a 1200 40hp if the serial mark ended with an X, but it doesn't. After the X there's an R. I checked multiple threads on theSamba forums, but all I could find was that the R does show up on blocks here and there, but no one knows what it means. I decided to let it go and assume I have a 1200. 

With that resolved I turned my attention to the crankshaft pulley. Volkswagen produced at least four different styles of pulleys. VW engines can sport a one-notch pulley, a dimple and notch pulley, a two-notch pulley, or a 3-notch pulley. To statically set the ignition timing, you have to line up one of those notches with the crack in the crankcase.

 I have the two-notch pulley, and the crack I'm talking about is right behind the pulley:

The first notch (on the left) sets the timing at 7.5 degrees BTDC (before top dead center), and the second notch sets the timing at 10 degrees BTDC. Before I owned the car someone painted a white mark on the pulley directly across from the first notch. I assumed that person knew what they were doing, and I set the ignition timing to that notch the first time I tried this. The YouTube videos I watched also confirmed that I should set the timing to that 7.5 degrees notch. The car seemed to run okay, but the engine would "diesel" which means it would sputter and rumble for few a seconds after I had turned the ignition off.

Turns out I didn't really need to decipher the mysterious code stamped on my engine. While I was researching "dieseling", I discovered that if you want to set your timing correctly, then what you really need to know is which distributor and carburetor you have.

I have the stock 28 PICT carb.

And I have a stock distributor. I had to use a mirror to see the model number that's on the back of it: Bosch 2V/ PAU 4R5. Some people call it this the "big cap" distributor.

This chart (read the bottom line) confirms that this carb/ distributor combination is right for a 1200 (40hp) engine.

And this combination should be timed at 10 degrees BTDC, not 7.5. Whoever painted that white mark on my pulley was wrong. So, on Tuesday night I redid my timing. I made all my adjustments when the engine was cold. I first checked to make sure the point gap inside the distributor was set at .016". Then I used a cheap test light like this to set my timing to the second notch.

Now the Bug actually stops running when I shut off the car, and it idles much better than it did. It also feels good to finally solve the mystery of the motor's origin. That one plagued Dad and I for over a decade. Too bad I can't talk to him up about it. I think he knows, but it would be nice to say, “Dad! I finally figured it out!” and then hear his reply.