How to adjust the timing on a 68 VW bug?

Answer 1

It's a multistep procedure and requires a timing light (it looks like a gun), a 30mm wrench, 10mm nutdriver, feeler gauges, a flat-tip screwdriver, a dwell-tach and a paint pen--you can get them at hobby shops. Start by opening the hood and turning the engine over with the wrench until you see the notch on the crank pulley. Paint it white so you can see it easily. (If you have a degree wheel--a crank pulley that looks like a protractor, forget the paint pen. But you probably don't have one.) Then set your valves--they affect the timing too. Plug the coil wire back in, and you're ready to proceed.

Anyway...hook up the dwell tach per instructions and set it to read RPMs on a four-cylinder engine. Hook up your timing light. Put the nutdriver very close to you so you can grab it easily, then go start the car.

Step 1 is to aim the timing light at the crank pulley and pull the trigger. If the white mark is aligned with the crack in the engine case, the engine is properly timed. If it's not aligned, loosen the nut on the distributor clamp and s-l-o-w-l-y turn the distributor while watching the white mark on the pulley. If it's going the wrong way, turn the distributor the other way. Once it's aligned, tighten the clamp and check your work by grabbing the accelerator lever on the carb and pulling it sharply toward you. If the car revs up freely, you're done with step 1. If you pull the handle and the engine dips in speed before it revs up, you need to adjust the timing some.

Step 2: Your dwell tach is in RPM mode. There's a recessed screw on the left side of your carb, if you have a single Solex (it might also say Brosol) carb. If the idle speed is 1500rpm--these engines idle quite a bit faster than you might be used to--you're at the right speed. If you're NOT there, you slow down the engine by screwing it in and speed it up by screwing it out. Turn it a little and wait till the speed stabilizes.

Step 3: put the dwell tach into DWELL mode. You want to see 50 degrees of dwell. This you will almost certainly have to change. Dwell is determined by point gap--the less point gap, the longer the dwell. Gap is determined by this little plastic thing that rides on the shaft in the distributor, and the little plastic thing wears out. To adjust the gap, turn off the engine, take off the distributor cap and remove the rotor, turn the engine over until the points are all the way open, then stick a .016" feeler gauge, which is the baseline starting gap, in the points, loosen the screw holding them down and retighten the screw. I've actually seen these have to be gapped to .010 to get the dwell right. Understand this now: DWELL IS THE ONLY THING THAT MATTERS HERE! If you have to set the dwell to .045" to get that 50 degrees of dwell, put it there. Or you can just do the smart thing, put a Pertronix Ignitor points eliminator in the distributor, and be happy with never having to screw with your dwell again.

Step 4: Once you have set the dwell correctly, the RPM will change. Readjust.

And step 5: if you changed the dwell and the idle speed, the timing will change too. They're all interconnected. This time use the force, Luke--just rev the engine and make sure it's working the way it should.

This is a very long, drawn-out description but this is one of the most time-consuming things on the car. There are so many factors involved here, it's ridiculous.

I have always done a 1500/3000/6000 interval: change oil at 1500 miles (every four weeks if you're driving the car at all), do the valves at 3000 and the timing at 6000. So the first Saturday of EVERY month you change your oil, the first Saturday of every other month you do your valves, and you time the car every other valve adjustment.