Volkszone Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
26 Posts
Discussion Starter · #1 ·
Just checking that I have this right!

Plugs 0.7mm
Valves 0.15mm COLD.
Points - mine are electronic
Timing 7.5 BTDC static. If I can't do static due to electronic points, then it should be at 7.5 notch with vac pipe off and blocked.

My dizzy is stock vacuum only advance type.

Cheers.
 

·
Registered
Joined
·
232 Posts
You can't time electronic ignition statically and it is not good trying to time it at idle. The ONLY safe way to time an aircooled VW engine is to use a timing gun to get around 28 to 30 degrees BTDC at 3000+rpm with vac ports blocked. Why? Because it is the only way you can check that your advance mech is working properly at the engine revs your vehicle uses when it is doing most work. I've been advising this for over 40 years because I have seen too many statically-timed engines cooked due to advance mech failure. This is especially important at a time when so many engines are running cheap Chinese dizzies with poorly built advance mechanisms.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #7 ·
You can't time electronic ignition statically and it is not good trying to time it at idle. The ONLY safe way to time an aircooled VW engine is to use a timing gun to get around 28 to 30 degrees BTDC at 3000+rpm with vac ports blocked. Why? Because it is the only way you can check that your advance mech is working properly at the engine revs your vehicle uses when it is doing most work. I've been advising this for over 40 years because I have seen too many statically-timed engines cooked due to advance mech failure. This is especially important at a time when so many engines are running cheap Chinese dizzies with poorly built advance mechanisms.
BJ1, thanks for the info.

My dizzy is vacuum only.

My crank pulley has a notch and a dimple.

I think I should set the timing by getting the notch at the case split, with the vacuum pipe off and blocked at the carb, at idle.

At idle, as soon as I connect the vacuum pipe the ignition advances a slight amount (maybe a degree or two), with the notch moving anticlockwise under the timing light.

More revs advances it further around.

Seems to drive ok now. No more backfiring.

The only issue to solve now is the occaisonal dying of the motor when coming off the gas at junctions. Doesn't do it all the time. I guess this is probably idle mixture settings on the carb?
 

·
Registered
Joined
·
232 Posts
Sounds like your timing is OK but I would still check with a gun that you are getting around 30 degrees with vac connected at 3000+ rpm. SV dizzies were abandoned by VW as they are unreliable - the diaphragm can leak giving less than the optimal advance. I would put an SVDA dizzie on that engine - preferably an original.

It also occured to me that your engine may not be a 1300. Most F engines that I take apart have 1600 B & Ps that have been fitted at some time in the engine's past. Doesn't alter the timing but may give a lean mixture if you are running a 30/31 single carb.

Your stalling problem is most often caused by valve clearances being too small. This holds the valves slightly off the seats when the engine is very hot. Suggest you recheck them. Unlikely to be idle circuit as it would stall even when the engine is cooler.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #9 ·
Sounds like your timing is OK but I would still check with a gun that you are getting around 30 degrees with vac connected at 3000+ rpm. SV dizzies were abandoned by VW as they are unreliable - the diaphragm can leak giving less than the optimal advance. I would put an SVDA dizzie on that engine - preferably an original.

It also occured to me that your engine may not be a 1300. Most F engines that I take apart have 1600 B & Ps that have been fitted at some time in the engine's past. Doesn't alter the timing but may give a lean mixture if you are running a 30/31 single carb.

Your stalling problem is most often caused by valve clearances being too small. This holds the valves slightly off the seats when the engine is very hot. Suggest you recheck them. Unlikely to be idle circuit as it would stall even when the engine is cooler.
Hi again, Is there an easy way to check for 1600 cylinders?

I'll double check for full advance, once I find my protractor!

I read that SVDA's aren't too good with Solex 30 carbs and need a 34 carb?

We used to have a Peugeot 306 that did exactly the same thing, the 'fix' was to drill a tiny air hole in the inlet manifold!
 

·
Registered
Joined
·
232 Posts
Hi again, Is there an easy way to check for 1600 cylinders?

I'll double check for full advance, once I find my protractor!

I read that SVDA's aren't too good with Solex 30 carbs and need a 34 carb?

We used to have a Peugeot 306 that did exactly the same thing, the 'fix' was to drill a tiny air hole in the inlet manifold!
The only way is to take the heads off but I doubt you want to do that! SVDAs work fine with 30 carbs. The vac signal is not entirely correct but the advance weights kick in before this becomes an issue. I've run SVDAs on 1500 engines with H30/31 carbs with no problems.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #11 ·
Just to confirm, this is what my pulley looks like - just noticed some saw cuts too!

Have I understood this correct?

30 degrees is, by my estimation about 90mm around the circumference from TDC.

292859
 

·
Registered
Joined
·
232 Posts
Blimey - I hope not! 30 degrees is around 42mm to the right of the TDC dimple, assuming it is a stock dynamo pulley. Easiest way is to set 30 degrees on a pair of straight dividers and hold them upside down with the pivot in the centre of the pulley and one arm on the dimple. Then mark where the other arm touches the pulley edge. You can make up a degreed paper pulley overlay from a template on page 6 of this Samba thread TheSamba.com :: Beetle - Late Model/Super - 1968-up - View topic - Timing Marks on Stock Pulley
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #13 ·
Blimey - I hope not! 30 degrees is around 42mm to the right of the TDC dimple, assuming it is a stock dynamo pulley. Easiest way is to set 30 degrees on a pair of straight dividers and hold them upside down with the pivot in the centre of the pulley and one arm on the dimple. Then mark where the other arm touches the pulley edge. You can make up a degreed paper pulley overlay from a template on page 6 of this Samba thread TheSamba.com :: Beetle - Late Model/Super - 1968-up - View topic - Timing Marks on Stock Pulley
Ha! Yes, you're right, 30 into 360 is 12 not 6! 45mm.

I found that the idle screw was a long way out (undone) so I wound it in until the motor slowed down slightly then wound it out about 1 whole turn. Idle speed is 750-800rpm.

We'll see how it runs.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #14 ·
Still playing up. Idles fine. Starts fine. I think it only dies if the engine is properly warmed up.

I checked the temps of the cylinders between 95 and 100C. The block was at about 75-80C, so not too hot.

The carb is cold.

When you come up to a junction and hit the clutch, the motor will drop to idle and then run slower and slower until it stops. It takes maybe 3-4 seconds. If you blip the gas, it will pick up and run.

I can't see any vacuum leaks,

I'm going to try a few more tests to see if I can narrow it down.

The air filter is set to summer with cold air going in and it's about 12 degrees C here at the moment.

Its an odd fault as you can leave the car running on idle for ages and it runs fine. I am guessing its the decelleration (high vacuum) that might cause the issue?
 

·
Highly Respected Member
Joined
·
13,498 Posts
What carb are you running ? it should say XX PICT X
As you say the carb is cold I'd set it to winter setting to draw hot air and see if it drives better. VW had to come up with several workarounds trying to get a single carb working reliably as the design suffers so much with icing and poor fuel atomisation due to the carb being so far away from the cylinder heads (i.e. the usual source of heat for carbs on most other engines).

Dave.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #16 ·
So the plot thickens....

The Carb is a Solex 30 PICT-2.

BUT today we lost all power from 3 & 4 cylinders.

I am guessing this is a bad air leak at the inlet manifold. It happened suddenly and didn't improve of get worse.

It's too grim outside today to investigate further, but I'll look at it more closely tomorrow.

If the idling problem was also an air leak, then maybe there;s a dodgy repair on the inlet manifold to head, hiding under the tinwork.
 
1 - 16 of 16 Posts
Top