SVDA Installation Instructions:
I have customized these instructions for my application. I have a Type 1 1600 Dual Port VW Engine with one center mount Weber Progressive carburetor. These instructions may or may not be correct for your application.
Use at your own risk
- Verify the vacuum line is connected to the correct port on the carburetor.
Note: The port should have the readings below:
At Idle - no vacuum
Idle to ½ throttle - vacuum
Over ½ throttle – almost no vacuum
- Disconnect the negative side battery cable.
- Put the emergency brake on and the transmission in neutral.
- Pull the distributor cap off of your current distributor, but do NOT remove the plug wires from the cap yet!
- Identify the #1 plug wire on the distributor cap, and mark its location.
- Turn the crank pulley until the ignition rotor is pointing to where the #1 plug wire is relative to the cap.
Note: TDC (Top Dead Center) on the crank pulley should be close to the centerline of the engine case, and this means you are firing on #1 TDC.
To remove your old distributor:
- A. If you are still running the old points system, remove the green wire running from the distributor up to the coil. It should be connected to the negative side of the coil.
B. If you are running a points replacement unit, there will be a black and a red wire running to either side of the coil. Identify which side of the coil the wire(s) came off of. It should be: Black goes to coil - (1), and Red to coil + (15).
- Loosen the distributor clamp and remove the distributor.
- Remove the cap and rotor from the new SVDA (Single Vacuum Dual Advance).
- Wipe off any excess oil, and give the points a quick clean with a Q-tip and rubbing alcohol. If you are running a points replacement unit, then skip steps 11 and 12.
- Rotate the distributor body until the rubbing block is on the peak of one of the four lobes on the distributor shaft.
- Using a feeler gauge, make sure the opening at the end of the points is .016" +-.001.
Note: To adjust points, loosen the flat head screw securing the points to the points plate, re-adjust, tighten, and re-check the point gap.
To Install the new SVDA Distributor:
- First put the distributor clamp on the distributor.
- Install the black rubber o-ring seal onto the distributor shaft.
- Wipe a little bit of clean oil on the o-ring.
- Remove the distributor cap.
- Slide the distributor in the engine case.
- Push down on the distributor shaft while rotating it.
Note: You should not be able to see the machined finish of the distributor shaft when the distributor is fully seated.
Note: Vacuum canister orientation should be facing toward you, and to the left (in the 7 o'clock position looking down on the SVDA).
- Check to ensure the distributor is fully seated.
Note: the ignition rotor should be able to rotate clockwise a very small amount. It is spring loaded, so it should return, counterclockwise, when you let go of the rotor.
- Remove the ignition rotor and the dust cover underneath it.
- Re-check the points gap (see steps 11 and 12).
- On the rotor is a small piece of felt. Put two drops of oil on it.
- Reinstall the dust cover while making sure the tab lines up with the notch in the distributor body.
- Install the rotor again.
- Connect the distributor up to the coil (see steps 7A and 7B).
- Rotate the distributor body until the ignition rotor lines up with the small line on the lip of the distributor.
- Rotate the distributor body clockwise about 1/16th of a turn.
- Re-install the distributor cap plug wires.
Note: The firing order should be: 1-4-3-2
- Connect the vacuum line up to the carburetor.
Note: Put a small 2" loop in the vacuum line, which prevents fuel from traveling down the hose from the carburetor.
To set the timing:
- Reconnect the negative side of the battery.
- Turn the key on, but do NOT crank the engine.
- With a test light grounded on the engine case, put the other end on the negative terminal on the coil.
- Slowly rotate the distributor counter-clockwise, until the test light lights up. Stop turning the distributor body as soon as the light turns on.
- Tighten down the distributor clamp.
- Start the engine.
- Check the timing at idle with the timing light.
Note: It should be at 7.5 BTDC
- Check the timing at 35000 RPMs, with the vacuum hose disconnected.
Note: It should be 28-30 Total Advance
- Connect the vacuum hose.
- Check timing at 35000 RPMs, this time with the vacuum hose connected.
Note: It should be 38-45 Total Advance
- Let it idle and re-check the timing at both idle and 3500 RPMs.
A new vacuum advance diaphragm needs a month or 2 of driving to break in and perform as it should.