Can't seem to nail down the timing

[beanlover]

I have a 205 T distributor with a single vacuum (SVDA SVA)
I have a Solex 30 PICT 2 carb
B6 Engine (which I know doesn't matter as much)

Everything I have found says timing should be 0*TDC with vacuum disconnected and plugged.

I assume that means disconnected from the intake and plugged...do I need to plug BOTH ports?

When I get the timing set at 0* with the RPMs at 850 it doesn't seem to have much higher end power and when I let off the gas to come to a stop it backfires.

Is 0*TDC correct for this combo? Everywhere I look says it is...but it doesn't seem to like it.

My pully has three marks as follows (4th mark is where I set it statically):

From what I understand the leftmost is 0*TDC. On my other engine that is actually 5*ATDC and there's a dimple for 0*. There is no dimple on this pully.

It seems like it likes to be set BTDC somewhere but I don't want to just randomly set it.

Advice please...thanks! Happy 4th to my U.S. bros and sisters!
_________________
'71 Super Beetle Convertible - Iberian Red - project that's not yet on the road

'71 Super Beetle Convertible - Clementine Orange - practically perfect in every way (ok not really...but she's a beauty!) - named Clarabelle

[Starbucket]

Do you see the white mark at the far right? disconnect and plug the hose from the carb. to dist. and rev the motor to 3000RPM and set the timing to that mark (make sure you set the points first) then reconnect the hose to the dist. and DON'T recheck the timing because you will get a false reading (that's why you disconnect the vacuum). take a drive and listen for any pinging when you step on the gas, if none you are good to go.

[Glenn]

Plug the port on the carb only
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
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[Pruneman99]

[Starbucket]

[goober]

I'd find a small hose that would attach to the vacuum diaphragm, pop the cap and using your mouth see if the diaphragm is fully moving the point plate.

Then hold the vacuum with your tongue and see if the diaphragm leaks down.

I set my 205T at a max of 28-30 deg. I believe a properly functioning 205T can advance up to 35 deg. So that sets my idle timing ATDC. To compensate I use a 04038 Bosch rotor with a wider brass tip.

Some say I'm doing it wrong but it works fine for me. I like/have a faster idle, it pulls great, I'm seldom over 3800 rpm and my loaded head temp is very good. Just about as good my brother using his SVDA.

[Pruneman99]

SVA = Single vacuum advance. NO MECHANICAL ADVANCE.

so if he set it to 30 degrees BTDC, he would be running 60-65 degrees advanced.

That distributor should advance 30-35 degrees if i remember. So TDC would be correct.

I didn't have time to cross check, so I didn't post. But your way is definitely wrong.

[vwoldbug]

Have you made sure the vacuum diaphragm is good and timing is advancing.

[Starbucket]

So the timing is set with vacuum connected or what? Those marks weren't painted on the pully for no reason (you don't know what has been done to the motor) so tell him how to set the timing that doesn't coincide to what i said.

[frenchroast]

Do this:
1. Line up the left mark with the case split line
2. Loosen the distributor clamp
3. Turn on the ignition (don't start it; just the ignition on)
4. Turn the distributor clockwise or counterclockwise until you hear a "click" or "pop".
5. You're set at 0° BTDC; tighten the clamp
6. As Goober described above, pull the cap and the hose off the carb vac port and suck on the hose until the base plate is fully advanced then plug the hose with your thumb. If the base plate holds, the diaphragm is good.

This a nice feature of the simplicity of the SVA and 30PICT2 carb; no test lights, timing lights, port plugging, mightyvac, etc. required. I did it this way when I was a teenager. The far right mark is probably a 32° mark. If you have a timing light, you can check the total advance doesn't advance beyond 32° but if you set initial advance at 0°, you'll be safe. Some motors might like a degree or two more initial advance but 0° is generally fine.

[goober]

[Pruneman99]

OK OP, post the entire distributor number, and the base plate number on the carb.

Most people refer to the 205T as the last digits of the common 113 905 205 T. Let's make sure that's what you have and not some other lesser used distributor that just ends the same and it's messing us up.

Post the base number on the carb also. I think it's on the driver's side base flange, but it could be somewhere else. Usually a 3 digit number.

[beanlover]

Thank you for all of the replies...sorry for the confusion!

I did, at first, say it was SVDA but had since discovered it was an SVA (but only by visually comparing it to others). The can is "skinny" and, when I tried to do the trick where you check the mechanical advance only there was absolutely ZERO advance without the vacuum...so I made an assumption. I will get the numbers of the distributor directly, but from the email when I ordered this in 2019 it stated 113 905 205 T as the numbers. I will look for the "base plate number" from the carb today.

Also...I made the white marks myself. Originally there were no marks except for the notches that come from the factory.

@frenchroast
I did almost as you described...I didn't listen for the pop. I used a light which worked in 2019 but, this time, it never went off like I expected. Instead I guesstimated where that far right mark should go based on my experience with my AE-block engine and then turned the distributor until the notch for cylinder 1 was being pointed at by the rotor. That was good enough to get it started at least.
I then used a timing light to get it to 0* but that's when the backfiring and lack of power started.
I did not check the vacuum diaphragm...I will do that today.

In looking at timing charts the only other option I could see was 7.5*BTDC for even older stock engines. I tried that and it did seem to like it a little better.

A weird bit of history on this engine: when I started working on it in 2019 I couldn't get it to start. The distributor was not even a VW distributor. This was all the info I received on it:

[frenchroast]

[Pruneman99]

OK well at least we know you're on the right track.

You should be timed to zero.

Check to make sure you are getting advance. Vacuum can is not leaking, vacuum port in carb is not blocked somehow.

Are you getting squirt from the accelerator nozzle when the throttle is opened?

Try another condenser like Frenchroast said. At idle, or light load a failing condenser may work ok. Under acceleration or heavy load, the engine will pop, fart, or cut out.

Also check your dwell angle.

[beanlover]

Thanks! I'll try a different condenser and see if that helps at all.
_________________
'71 Super Beetle Convertible - Iberian Red - project that's not yet on the road

'71 Super Beetle Convertible - Clementine Orange - practically perfect in every way (ok not really...but she's a beauty!) - named Clarabelle

[Starbucket]

[ashman40]

Here's the link to the Old Volks Home data for that model distributor (on the type2.com site):
http://www.type2.com/~keen/ignition.html#A6970M
At the bottom of the specs you can see specific timing advance based on applied vacuum to the canister. You can test this using a vacuum hand pump with a gauge. At idle, plug the vacuum port at the carb end and note the warmed up timing. Apply vacuum to the vacuum canister on the distributor and note the increase in timing as you increase the vacuum. It should be similar to what is listed in the specs. If you see less advance you may need a new canister.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[beanlover]