Pertronix SVDA install?

[72Hardtop]

Hey Colin,

Got that Pertronix SVDA installed. After getting the rotor at (TDC #1 timing scale at 0) with the old distributor (German 009) installed the rotor on it pointed towards you. Once I removed it and installed the SVDA the rotor on it faces just about 3' O'clock. The vacuum can itself is pointed at the 2' O'clock position roughly. I initially timed it with the vac line off & plugged after routing the lines to the Weber vac ports. I found that setting the SVDA at 7.5 BTDC it would quit advancing at 32 degrees ~ 3500RPM's. So I bumped it down to 28 fully advanced and it idles at ~5 BTDC (RPM 900). I thought it was supposed to be at 7.5 BTDC??? Or is that just initially...or does it even matter?

I had to reset the carb mixture screws after noticing it would miss a bit at idle but it's nice and smooth now. As far as being able to tell the difference compared to my old German 009...tough one, perhaps slightly. Maybe once the vac diaphragm breaks in it will become more readily apparent.

As for the idling at ~ 5 BTDC does/would that have anything to do with the cam profile perhaps, new distributor? With my old German 009 it would idle at 12 and advance to 28 full. I don't expect them to be the same though.

[Amskeptic]

Hey Colin,

Got that Pertronix SVDA installed. After getting the rotor at (TDC #1 timing scale at 0) with the old distributor (German 009) installed the rotor on it pointed towards you. Once I removed it and installed the SVDA the rotor on it faces just about 3' O'clock. The vacuum can itself is pointed at the 2' O'clock position roughly. I initially timed it with the vac line off & plugged after routing the lines to the Weber vac ports. I found that setting the SVDA at 7.5 BTDC it would quit advancing at 32 degrees ~ 3500RPM's. So I bumped it down to 28 fully advanced and it idles at ~5 BTDC (RPM 900). I thought it was supposed to be at 7.5 BTDC??? Or is that just initially...or does it even matter?

I had to reset the carb mixture screws after noticing it would miss a bit at idle but it's nice and smooth now. As far as being able to tell the difference compared to my old German 009...tough one, perhaps slightly. Maybe once the vac diaphragm breaks in it will become more readily apparent.

As for the idling at ~ 5 BTDC does/would that have anything to do with the cam profile perhaps, new distributor? With my old German 009 it would idle at 12 and advance to 28 full. I don't expect them to be the same though.

Idle timing is not an important parameter. Get the 28* dialed in and just note where your idle timing happens to be.
Some distributors have a very narrow range 28-12 and others have a sloppy range 28-2, some are close to factory specs of 28-7.5.

Some VWs had a vacuum retard so the induction system could pass huge quantities of air at idle for emissions reasons.
Some VWs (Raby engined, for example) could really use the narrow range to help their performance cams idle decently.

Vacuum diaphragms do not "break in". Please reply with a vacuum advance timing number. Feather the throttle at 3,000 rpm with the vacuum advance operational (feathering spikes the vacuum) and read the max advance, it should be near 38-40*BTDC. You might have a lousy vacuum signal.
Colin

[72Hardtop]

Just going by what John from Aircooled told me. He said that the vac can diaphragm would be stiff and require about 1000~2000 miles of drive time before I'd see the full amount of vac advance. Right now it appears to fully advance (hose connected) to roughly 33 or so when mildly blipping/feathering the throttle around 3500-3800rpm. This is with the bus parked no load on engine. I have known of those running performance cams having less overall vacuum advance with these engines. Hit or miss. It does accelerate more smoothly. I would think that some vacuum advance is better than none at all.

[72Hardtop]

Advances to 32-33 degrees with hose on. I'll give it 1500-2000 miles then give a final tally on total advance. One other thing the vac lines come from #1 and #4 barrels on the Webers then 'T' then onto the distributor. Is it possible that the vac signal could be kinda quirky given the 4 stroke arrangement and the fact that the vac lines are arranged the way the are?

Thinking of putting an anti pulse valve before the vac can to see if it helps.

[Amskeptic]

Just going by what John from Aircooled told me. He said that the vac can diaphragm would be stiff and require about 1000~2000 miles of drive time before I'd see the full amount of vac advance. Right now it appears to fully advance (hose connected) to roughly 33 or so when mildly blipping/feathering the throttle around 3500-3800rpm.

Phooey.

Let me know if it does increase.
Colin

[Bleyseng]

Vac can break in? That's a new one on me.

[Amskeptic]

Vac can break in? That's a new one on me.

Yeah, didn't you read your owner's manual?

"Please note that your brakes may not stop the car for a couple of weeks as the brake diaphragm 'breaks in.'"
(that's why everybody misspells "brakes")

and . . .

"use caution when merging onto highways until your vacuum advance unit breaks in."

I think that is John's way of swatting pesky customers away. Really, so many dual monster carbs have no vacuum signal and lousy brake booster vacuum . . .
Colin

[72Hardtop]

The following are the instructions John sends out after purchasing SVDA. In time we'll see...

SVDA Installation Instructions - provided by Aircooled.Net

First, it's very important that you verify the vacuum line is connected to the correct port on the carb or throttle body. The port you want should have

0 vacuum at idle
vacuum from off-idle to 1/2 throttle
almost no vacuum over 1/2 throttle.

If you are getting these readings, then you are A-OK to continue.

As with any procedure where the electrical system is involved, begin by disconnecting the negative side battery cable. Next, make sure the emergency brake is on, and put the car in neutral. Pull the distributor cap off your current distributor; Do not remove the plug wires from the cap! Now, just in case your distributor drive pinion was installed incorrectly, follow the plug wire from the #1 plug, to the distributor cap, and note it's location. Rotate the engine by turning the crank pulley nut with a wrench until the ignition rotor is pointing to where the #1 plug wire is relative to the cap. TDC on the crank pulley should be fairly close to the centerline of the engine case, and this means you are firing on #1 TDC. The reason you put the engine to #1 TDC before starting is so that when you install the SVDA, you KNOW the rotor should be aiming at #1. You rotate the SVDA body so the vac can is in an appropriate location and the rotor is aiming to a plug terminal. Then install #1 wire, and the others in firing order.

It's important to note that you MUST CHECK that the SVDA is aiming at #1. All distributors DO NOT aim at the same place relative to one another. So check it! The "notch" that indicates the location of #1 IS NOT TO BE USED NOR TRUSTED. Because of the different rotor orientation of so many distributors, and so many different orientations of the drive pinion (during installation), just ignore the notch. If you like having one, put your own in after getting the distributor running. But do not assume the notch will be "#1" because the notch is just as likely to be wrong then right.

If you already know for sure that the distributor drive pinion is installed correctly, you do not need to worry about following the #1 plug wire to locate TDC for #1 cylinder, we are just trying to save you a headache! People often remove the old distributor and are "surprised" that THERE IS NO STANDARD ROTOR POSITION. IOW, different distributors put the rotor in a different place. Now you know why it's a wise idea to put the engine to #1 TDC before starting.

Now you are ready to remove your old distributor. If you are still running the old points system, simply remove the green wire running from the distributor up to the coil. If you are running a points replacement unit, such as a Pertronix or Compufire, there will be a black and a red wire running to either side of the coil. Note which side of the coil the wire(s)came off of, to avoid any confusion when connecting the system back up. This is important, as connecting them to the wrong side of the coil, will ruin a points replacement module the moment the key is turned on. Black goes to coil - (1), and Red to coil + (15). If the green wire (points) is wired to coil + (the wrong terminal), the points and possibly your entire wiring harness can be fried, so make sure this is correct!

Enough with the warnings, let's continue! Loosen the distributor clamp. This is easiest with a 10mm socket and ratchet with an extension, or a 10mm wrench on a T-4. You do not need to remove the nut completely, just loosen it so that it is no longer pulling the clamp together. Sometimes the distributor can be a pain to get out, since they are a tight fit through the distributor clamp, due to the rubber o-ring seal on the distributor shaft. With some pulling and twisting, it will come out. Some folks remove the dist clamp along with the distributor (this is fine too).

Remove the cap and rotor out of the SVDA, and adjust the points. Sometimes there is some oil inside the SVDA, you should wipe the excess off, and give the points a quick clean with a Q-tip and rubbing alcohol if you are retaining the points. Gap them to .016" fully open.

Now you are ready to install your new SVDA distributor. We like to put the distributor clamp on the distributor first, THEN install the black rubber o-ring seal onto the distributor shaft. This way you do not have to fight the clamp over the fat/new o-ring. You can use the old one off your old distributor if it is still in good condition, but the seals are cheap, so a new one would be preferred as cheap insurance. Get a little bit of motor oil and wipe it on the o-ring. If your engine oil is fairly clean, you can get some oil off your dipstick for this, since you only need enough to put a thin coat on the o-ring. This will help it slide in easier, and reduce any chance of the o-ring tearing on a sharp corner of the engine case. Remove the distributor cap, and with the distributor slid in the engine case, push down on the distributor shaft while rotating it. This will allow the offset keyway that is on the end of the distributor shaft to fully seat into the distributor drive pinion. If the distributor does not fully seat against the distributor clamp and engine case, the distributor drive pinion might not engage the distributor to rotate it, or if it is not down all the way, it might run for a while until the distributor lifts slightly and disengages from the drive pinion. You should not be able to see the machined finish of the distributor shaft when the distributor is fully seated. Vac can orientation depends on the engine you have. Upright engines should put the vacuum canister facing toward you, and to the left (in the 7 o'clock position looking down on the SVDA). On T-4 engines the vac can only really fits in one place, so it obviously goes there (around 2-4 o'clock).

With the distributor fully seated, 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. This is the centrifugal advance part of the distributor, and is how it should be. The next thing to do, would be to remove the ignition rotor, and the dust cover underneath it. Although the SVDA distributor cores are new Bosch, it is highly suggested that you re-check the points gap, since YOU want to be the one responsible for how it runs, not some guy in the assembly line 5k miles away! To do this, look at the ignition points in the distributor. You should be able to identify the moving arm of the points unit. If you look closely you will see a small rubbing block that rides against the distributor shaft. Rotate the distributor body until the rubbing block is on the peak of one of the 4 lobes on the distributor shaft. Using a feeler gauge, make sure the opening at the end of the points is .016" +-.001". If it is not, loosen the flat head screw securing the points to the points plate, re-adjust, tighten, and re-check the point gap. If you are installing a points replacement unit at this time, simply follow the instructions supplied with the product, or if you are re-using a previous points replacement unit, make sure that it is a points replacement unit compatible with vacuum advance distributors. If your points replacement unit was from a centrifugal advance distributor (such as a 009 or an 050), then you will have to run get a different one, since the points replacement units for the 009/050 are NOT compatible with the SVDA or any other vacuum advance distributor.

If you run points, it is wise to have the dust cover that resides below the rotor in place, to minimize dirt and water from accumulating there.

After you have checked the points, note the top of the distributor shaft. The top of the shaft is hollow, and there is a piece of black felt in the cavity on top. The felt is already oiled, but you must be sure to remember, each time you change your engine's oil, to put 2-3 drops of oil on the felt to lubricate the distributor where the engine's oiling system doesn't reach. This will prolong the life of the advance mechanism of the distributor.

Now, re-install the dustcover, making sure the tab lines up with the notch in the distributor body, and install the rotor again. Connect the distributor up to the coil, making sure that you connect the wiring up as it was before. Just in case you are going from a points replacement unit back to points, the green wire from the distributor will go to the negative side of the coil. If you aren't sure which side of the coil is the negative side, a Bosch coil will have the numbers "1", and "15" by each terminal post. The number "1" side is SUPPOSED to be negative, and the "15" side is SUPPOSED to be positive. If the coil is wired backwards, it will "work", but not nearly as well as when the polarity is correct). The negative side of the coil shouldn't have any wires going to it, except a wire to the distributor, and if the car has a tachometer installed, one more wire for that. The positive side terminal will have a black wire going to it, supplying the 12 volts to the coil, then, depending on what parts are on your engine, it may run a wire off that terminal to the automatic choke element and the idle run-on solenoid, and also the reverse light switch (if equipped).

Now, 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 a 1/16th of a turn. Re-install the distributor cap supplied with the SVDA, and transfer the plug wires from the old cap (the wires should still be hooked to it at this point!) one at a time to ensure that the wires do not get mixed up. Make sure the plug wire that was #1 on the old cap, is going to the #1 spot on the new cap, which is where the rotor is pointing. The wires will go around the distributor cap clockwise, in the firing order 1-4-3-2 (this is 1-2-3-4 CCW). You can then connect the center coil wire at this point. Now connect the vacuum line up to the carburetor. On most Solex applications, the proper port for the vacuum advance is on the left side of the carb, right by the two adjustment screws. If the application is with dual carbs, hook the vacuum line up to both carbs using a "T", on an appropriate vacuum port. A vacuum advance distributor does not get it's signal from the intake manifold, so do not hook the lines up to the balance tube that a lot of single barrel, dual carb setups have. If you have a set of carbs that do not have vacuum ports on them, such as Kadrons, we can perform this modification to your Kadrons. Since the carbs sit higher than the distributor, it is a good idea to put a small 2" loop in the vacuum line, which prevents fuel from traveling down the hose from the carb, and into the vacuum diaphragm on the distributor, which can cause failure of the vacuum diaphragm. This is not something you absolutely have to do, but the cost of the extra length of hose is minimal, and again, is cheap insurance.

Now it's time to set the timing. Reconnect the negative side of the battery, and turn the key on, but don't crank the engine. With a test light grounded on the engine case, put the other end on the negative terminal on the coil. Very, very slowly, rotate the distributor counter-clockwise, until the test light lights up. The light will stay lit up for a few degrees of the rotation, so it is important to stop turning the distributor body as soon as the light turns on, when rotating counter-clockwise. After this, simply tighten down the distributor clamp, and your engine should start right up. If you have a timing light, get the car started up, aim for 7.5 BTDC at idle FOR NOW, the hose connected or not should not matter (if it does that's the wrong vacuum port). After you set that, reconnect the vacuum line. Depending on where your timing was at idle with your old distributor, you may need to re-set your carb. To verify the correct operation of the SVDA, the timing should be

A) 28-30 Total Advance (hose disconnected)@ 3500 RPM.
B) 38-45 Total Advance (hose connected)@ 3500 RPM.

Let it idle and re-check the timing, you can now use this timing setting to set the timing at idle, though we do recommend you check the full advance settings to make sure the SVDA is working properly at both idle and full advance.

Do NOT be alarmed if you do not get the full amount of vacuum advance coming in right away; the vacuum advance diaphragm is new and is VERY STIFF, it make take up to a month or two of driving (A month sitting in your driveway or garage is not the same) to loosen up as it's used.

This distributor will result in engine and oil temps 15-20 degrees lower then centrifugal only distributors (like the 009, 010, 019, 050, or others), and 3-6 MPG better mileage (we have had customers report 8mpg improvement, we do not promise this), not to mention better throttle response and cleaner running! We are convinced you'll be amazed at the smooth performance of our SVDA product, and hope you'll tell everyone about it!
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Use these instructions AT YOUR OWN RISK. Aircooled.Net, Inc. does not assume any liability for damages incurred while following these instructions nor while installing any product purchased from Aircooled.Net. We strongly recommend that you consult a shop manual for further information. If you do not feel confident installing the products, consult a mechanic. Portions of these instructions may be a reproduction of manufacturer's instructions, reprinted with permission. These instructions are COPYRIGHT Aircooled.Net, Inc. and may NOT be reprinted or distributed without permission.