“Two sparks forward…”
… and one spark back. MrsDoF is out of town, so my son and I are batching it this weekend. He (possessing an actual social life) is busy, so I’m pretty footloose and fancy-free.
Hah! Time to work on my Bug. This 1967 sculpture of a car is a long-running joke, whose punch line may become less useful if I ever get it running satisfactorily. Which is to say, as I remember how the ‘67 I had in college ran.
Yesterday and today I installed a Pertronix magnetic pickup in the distributor, eliminating the “points and condensor” that used to keep mechanics in boat payments.
Getting a classic bug running well today is a bit more challenging than it used to be due to the limited availability of vacuum-advance distributors among other variables. (Most VW parts places sell a Bosch 009 centrifugal-advance, which is fine for industrial applications like compressors or generators that use the VW engine, but not so good for, well, cars.)
Add to this the problem that gasoline now contains up to 15% alcohol, which isn’t a great match for the 34PICT-3 carburetor that VW used with the “late-model” 1600cc engine. So there’s lots of urban legend and lore about getting smooth response.
I am using Aircooled.net‘s SVDA distributor and a beautiful NEW German 34PICT-3 carburetor, both set to specifications, and result is great… sort of.
At the moment the car is running smoothly and strongly – actually better than it has since I dove headlong into this crazy project. But it’s hot. The engine is really toasty after only short periods of running. Last night it died on me, possibly from heat-induced vapor-lock.
The timing is 30 degrees max with the vacuum hose plugged (which is to say, centrifugal only). It maxes out at about 40 degrees (!) at 3000 rpm with the vacuum connected, which seems like a lot but according to Aircooled, that’s about right.
There’s no “flat spot” of power-loss on throttle application, which is the problem the SVDA distributor is supposed to address. It’s really very nice! So why is it running so hot?
Could be the gas. The tank is full of gas that (I now realize) is 8 months old and may not be fully burning before it leaves the ignition chamber. I’m going to add some StaBil to it (which I should have done last Fall) to see if that helps. (Update: I drained out the gas and replaced it with fresh premium, and the engine stopped dying but is still really hot. Anyone know what to do with 10 gallons of old gas?)
On another note, if you’re running a classic VW, get one of these laser-engraved pully wheels. It makes setting the timing SO much easier. No more guessing which type of pully wheel you have, and how far around the (unmarked) pully is 30 degrees. There are enough variables to driving a 37-year-old car; don’t add guesswork to them.
By the way, the pully wheel in this picture was spinning at 850 rpm when this picture was taken. That’s about 14 revolutions per second! The pully wheel is about 6.75 inches across, which is about 21 inches around for an edge surface speed of 25 feet per second, or roughly 17 miles per hour. Yet it rendered sharply because this is a flash picture. My little digital camera has a tiny flash which equals a very short duration.
(I rounded those figures starting with the estimate of the pully wheel diameter, so you calculator people just put those extra decimal places back where you got ‘em.)