TheSamba.com :: View topic - SVDA Pertronix Distributor Timing Question

Mon Feb 19, 2024 11:58 am

I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

Mon Feb 19, 2024 12:09 pm

7.5° BTDC is a good starting point for your distributor.
Sometimes an engine will like more initial timing.

Pull the vacuum line and plug the carb nipple. Start the engine a warm it up.
With a timing light rev the engine until the timing stops advancing. Somewhere between 28-30° advance would be ideal engine timing.
Make sure to unplug the vacuum nipple on the carb and replace the vacuum line to the distributor.

Take the car for a drive and see how it's running for ya.

Mon Feb 19, 2024 12:44 pm

The 5° ATDC specification is for DVDA distributors only (which have a vacuum retard function, for emissions control purposes at idle) -- it's n/a for SVDA type distributors.

For your purposes, recommend sticking with the 7.5° BTDC setting advised above.

Mon Feb 19, 2024 1:15 pm

Actually you want to time it 32* BTDC @ 3500rpm with the vacuum hose disconnected and the port of the carb plugged.

The mechanical advance on the aftermarket distributors can vary so you want to limit it to 32* max.

You will need a timing light.

Mon Feb 19, 2024 1:24 pm

I purchased an Innova 3568 Digital Timing Light with Tachometer that will be delivered tomorrow.

Glenn wrote: Actually you want to time it 32* BTDC @ 3500rpm with the vacuum hose disconnected and the port of the carb plugged.

The mechanical advance on the aftermarket distributors can vary so you want to limit it to 32* max.

You will need a timing light.

Mon Feb 19, 2024 1:27 pm

So set it at 7.5* BTDC and static time it, then warm up the car and at 3500 RPM it should be at 32* BTDC with the vacuum hose disconnected & carb plugged?

baldessariclan wrote: The 5° ATDC specification is for DVDA distributors only (which have a vacuum retard function, for emissions control purposes at idle) -- it's n/a for SVDA type distributors.

For your purposes, recommend sticking with the 7.5° BTDC setting advised above.

Mon Feb 19, 2024 1:29 pm

correct

Mon Feb 19, 2024 1:48 pm

Howdy ...

Ideally you should follow this order :

Valves (cold)
Point gap
Carburetor (fully warm)

Then utilize great advice above.

Get-er-dun ... stay safe

jinx

Mon Feb 19, 2024 2:30 pm

another thing... when the carb is plugged, should the vacuum hose also be squeezed off with a pair of vice grips or something?

Mon Feb 19, 2024 2:32 pm

No need.

Mon Feb 19, 2024 2:41 pm

Thanks!! I'll let yall know how it turns out when I get a chance later this week to get this done.

Mon Feb 19, 2024 4:18 pm

Glenn wrote: No need. And no need to plug it. No load on the engine.

Mon Feb 19, 2024 8:21 pm

RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

FYI- Since you're new to VW's be aware that those Chinese Pertronix distributors are a low quality part with lots of issues out of the box. All the new Chinese parts for VW's are terrible. "If" you can get the timing set somewhat close, hook up a hand vacuum pump to the vacuum canister. Make sure the pivot plate actually pivots. Lots of times they are locked up. The pivot guide is set way to lose so the pivot plate can rock back and forth affecting dwell. The advance weights also like to not come out and retract correctly and you'll see timing scatter.

I've autopsied many new Chinese distributors. All were junk with poor quality materials, sloppy tolerances and build quality. Some I couldn't even get to work correctly on my Sun distributor machine.

Mon Feb 19, 2024 8:42 pm

RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

Lots of people run those distributors and have a lot of success. Timing at 7.5 degrees at idle or at 32 degrees max advance are the two most common ways to set the timing.

Mon Feb 19, 2024 8:45 pm

heimlich wrote: RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

Lots of people run those distributors and have a lot of success. Timing at 7.5 degrees at idle or at 32 degrees max advance are the two most common ways to set the timing. But only one way is right.

Mon Feb 19, 2024 8:51 pm

bsairhead wrote: heimlich wrote: RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

Lots of people run those distributors and have a lot of success. Timing at 7.5 degrees at idle or at 32 degrees max advance are the two most common ways to set the timing. But only one way is right.

Ideally they should both land you in the same spot. There's one problem with using the max advance and that is if the vacuum canister over advances. It can lead to a hole burnt in the piston. The OEM canisters are limited. The aftermarket ones can over advance.

Mon Feb 19, 2024 10:57 pm

heimlich wrote: bsairhead wrote: heimlich wrote: RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

Lots of people run those distributors and have a lot of success. Timing at 7.5 degrees at idle or at 32 degrees max advance are the two most common ways to set the timing. But only one way is right.

Ideally they should both land you in the same spot. There's one problem with using the max advance and that is if the vacuum canister over advances. It can lead to a hole burnt in the piston. The OEM canisters are limited. The aftermarket ones can over advance. I had no idea a vacuum advance could go further than the all in mechincal. Learn something new every day.

Tue Feb 20, 2024 4:57 am

bsairhead wrote: heimlich wrote: bsairhead wrote: heimlich wrote: RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

Lots of people run those distributors and have a lot of success. Timing at 7.5 degrees at idle or at 32 degrees max advance are the two most common ways to set the timing. But only one way is right.

Ideally they should both land you in the same spot. There's one problem with using the max advance and that is if the vacuum canister over advances. It can lead to a hole burnt in the piston. The OEM canisters are limited. The aftermarket ones can over advance. I had no idea a vacuum advance could go further than the all in mechincal. Learn something new every day.
What did you think the vacuum was for?

Tue Feb 20, 2024 6:37 am

wcfvw69 wrote: RyanDunn1977 wrote: I am new to Beetles and recently got a 72 Super Beetle DP 1600, running a SVDA Pertronix Distributor with electronic ignition and 34 Pict 3 Carb. I am trying to get the timing set but not sure on where to time it. I have seen youtube videos for static timing at TDC and 7.5* BTDC and in the "How to keep your volkswagen alive" manual at 5* ATDC Any help would be appreciated, thanks.

FYI- Since you're new to VW's be aware that those Chinese Pertronix distributors are a low quality part with lots of issues out of the box. All the new Chinese parts for VW's are terrible. "If" you can get the timing set somewhat close, hook up a hand vacuum pump to the vacuum canister. Make sure the pivot plate actually pivots. Lots of times they are locked up. The pivot guide is set way to lose so the pivot plate can rock back and forth affecting dwell. The advance weights also like to not come out and retract correctly and you'll see timing scatter.

I've autopsied many new Chinese distributors. All were junk with poor quality materials, sloppy tolerances and build quality. Some I couldn't even get to work correctly on my Sun distributor machine.

Absolutely true!!!

Tue Feb 20, 2024 7:51 am

bsairhead wrote: I had no idea a vacuum advance could go further than the all in mechincal. Learn something new every day.
They work together. The concept is that a "low-density" mixture (like what you get at partial throttle) burns slower than a "high-density" mixture (e.g. what you get at WOT). So at partial-throttle settings (light engine loading -- e.g. cruising at highway speeds, decelerating, etc.), you need more advance to fully burn the mixture and get maximum power out of it. That's what the vacuum advance helps provide.

Conversely, when you "stomp on it", you now have high-density mixture that burns faster, so less advance is required. The vacuum advance goes away in that case, and only the centrifugal (mechanical) advance is present. This helps prevent pre-ignition "pinging"/damage.

In any case, you want both the mechanical and vacuum advance systems working properly and set correctly to get maximum power & fuel economy out of your engine, plus prevent damage to it.