Timing with Vac advance Dizzy

[creationblue]

Just reading Leons post asking about timing with a 009, what is the word on the street with a Vac dizzy, Im sure this is done all the time and maybe not always correctly, I know I struggled to find/understand a definative answer to this. My understanding is that it differs to the afor mentioned unit..............

Just

 

[NickJ]

I'm a believer in the John Muir method, statically timed using a test lamp. I find all his explanations very easy to follow and understand, if you haven't got his book it is well worth the money and a good read in it's own right. Nick.

 

[creationblue]

The trouble is John Muir's book says my '70 should be timed at 0DegBTDC, then this is VW Resource's advice 'Vacuum-advance only distributors: From 1961 to 1971, Type 1 distributors were vacuum-advance only -- they had no centrifugal advance. These distributors are timed at 7.5o BTDC; this point is found by measuring on the rim of the crankshaft pulley 11.5 mm to the right of the TDC notch.'
Confusing :roll:

Ok I will add to this as I find info
1. If you have a SINGLE vacuum distributor, the vacuum hose must be removed from the distributor and plugged so that air will not be sucked into the carburetor.

2. The correct timing setting for the centrifugal advance distributor (009) AND the single-vacuum distributor (vacuum hose plugged) is 7.5o Before Top Dead Center (BTDC). This means that as you view the 7.5o mark at the crankcase split (with the strobe), the TDC mark on the pulley will be about 11.5mm to the LEFT of the crankcase split when the distributor is properly timed.

 

[Tofufi]

It depends on the exact distributor part number.

SP and TP engines often have different engine timings.

Find your distributor part number here:

http://www.oldvolkshome.com/ignition.htm" onclick="window.open(this.href);return false;

Let us know what you reckon it should be. Some distributors (such as the 5 deg ATDC ones) shouldn't be used any more without being converted to the 7.5BTDC vac can type...

 

[noddy]

If you time your distributor staticaly ie at tickover, its worth checking what its full advance is.

Ive had a second hand single vac advance dissy that went up to 36 degrees before TCD, every thing Ive read says that 32 degrees is the absolute max an aircooled engine should run at when fully advanced.

If you want to go further in checking a dissy you will also need a vac gauge to check the change points in the advance curve.

 

[aogrady]

The trouble is John Muir's book says my '70 should be timed at 0DegBTDC, then this is VW Resource's advice 'Vacuum-advance only distributors: From 1961 to 1971, Type 1 distributors were vacuum-advance only -- they had no centrifugal advance. These distributors are timed at 7.5o BTDC; this point is found by measuring on the rim of the crankshaft pulley 11.5 mm to the right of the TDC notch.'
Confusing :roll:

Ok I will add to this as I find info
1. If you have a SINGLE vacuum distributor, the vacuum hose must be removed from the distributor and plugged so that air will not be sucked into the carburetor.

2. The correct timing setting for the centrifugal advance distributor (009) AND the single-vacuum distributor (vacuum hose plugged) is 7.5o Before Top Dead Center (BTDC). This means that as you view the 7.5o mark at the crankcase split (with the strobe), the TDC mark on the pulley will be about 11.5mm to the LEFT of the crankcase split when the distributor is properly timed.

Hi!

Now i'm confused where to set my timing. I have a notch on my pulley which i guess is TCD, so before the notch (left) is BTDC and after the notch (right) is ATDC? :?: :?
I have a AE bug engine in my bus with a VW 113-905-205AJ dizzy, see below info from Old Volks Home............

Beetle 1971 * 1600 Manual Trans

Distributor: VW 113-905-205AJ, Bosch 0231 167 049 > 043-905-205C, 0231 176 028
Can Use: VW 113-905-205AN, Bosch 0231 167 070 or 043-905-205C, 0231 176 028
Points: 01 011
Points Replacement Plate Assy: VW 311-905-227A, Bosch 1237 110 064
Condensor: 02 054
Rotor: 04 033
Dust Cover: 039-905-241, Bosch 1230 500 139 > 1230 500 147
Cap: 03 010
Distributor Cap Clip: 034-905-265, Bosch 1231 251 033
Parts Kit (Shims, Washers & Hardware): 059-998-211, Bosch 1237 010 007
Coil: 00 015 (Blue Coil: 00 012)
Vacuum Can: 07 223 (1237 122 969) (Formerly 07 091 [1237 121 851]
Ignition Wires: 09 001
Spark Plug: W8AC
Timing Set At:: 5deg ATDC @ 800-950rpm w/strobe, vacuum hose(s) connected.
Advance/Retard Range: Vacuum: 9-12deg Adv, 11-13deg Ret; Centrifugal: 6-12deg @ 1500rpm, 22-25deg @ 3800rpm

Right, it says on vw resource in reply to a question someone posted........

The 5 degree ADTC setting some others have described to you is for the 1971-1973 1600 twin port engine (AD, AE series engine numbers) with the DOUBLE vacuum distributor (two vacuum lines to the carburetor). NEVER use this setting with the 009 distributor or any single vacuum distributor or the car will be badly underadvanced at higher rpms, which will result in overheating and poor economy. For your information, the double vacuum distibutor pulled in 5 degrees ATDC at idle as an emissions thing - when you crack the throttle open the retard drops out and the timing jumps to a normal 7.5BTDC and starts to advance from there. The double vac distributor was used for only three model years, then VW used the single vacuum double advance (SVDA) distributor - from the '74 year onwards. It's like a high quality 009 (up to 32 degrees) with added vacuum advance (an additional 8 degrees when needed) - the best of both worlds.

And regarding timing the different dizzys....................

Timing the Various Distributors -

Note: The double-vacuum advance distributor must be timed with the engine idling, using a strobe timing light. The 009 and single-vacuum distributors CAN be statically timed at 7.5o BTDC, but timing with a strobe light is recommended. If an electronic ignition system like Compu-Fire or Pertronix has been installed, the distributor MUST be timed with a strobe light.

Vacuum-advance only distributors: From 1961 to 1971, Type 1 distributors were vacuum-advance only -- they had no centrifugal advance. These distributors are timed at 7.5o BTDC; this point is found by measuring on the rim of the crankshaft pulley 11.5 mm to the right of the TDC notch.

Dual-advance distributors: From the TDC mark, measure on the rim of the pulley 7.6 mm to the left from the TDC notch and mark with white paint; this is 5o ATDC, the point at which the dual vacuum advance distributor is timed.

009 and SVDA distributors: Measure on the rim of the crankcase pulley 11.5 mm to the right of the TDC notch. This is 7.5o BTDC; mark this point with white paint. This is the point at which the centrifugal advance (009) and single-vacuum dual-advance (SVDA) distributors are preliminarily timed (the maximum advance at 3500 rpm will be the final timing point for these distributors).

Maximum advance: From the TDC mark, measure on the rim of the crankcase pulley 46 mm (for a 175 mm diameter pulley) to the right of the TDC notch. This is 30o BTDC; mark this point also with white paint. This is the maximum advance point at 3500 rpm, the timing point for 009 and SVDA distributors.

So according to OVH, my bud dizzy is a 71 vac only no mech advance, so how come with the vac pipe not connected, and when i rev the engine the strobe goes round to the left? Surely that means that it is both vac and mechanically advanced?

So this being the case, should i be 7.6mm (left) before the mark for 5 ATDC, or 11.6mm after (right) the mark? Or am i getting confused over which way is ATDC and BTDC???
Also i read somewhere that AD engines have the notch at 5 not TDC, so that aint helping, but my engine is a AE??

And can anyone tell me, now that i am confused, where to set the bloody timing!! :evil:

Cheers!

Alistair

 

[noddy]

If your stuck time it dynamically at about 30 degrees before TCD at around 3000 rpm, dynamic timing is a better option that static.

Will will need either a strobe with an advance function or a timing scale on the case, use the TCD mark for number one cylinder, if you not sure which one it is take the plug out on number 1 and turn engine over by hand till the piston is at the top of its stroke, I use a socket extender when Ive done this, then see which mark is in line with the case. You may need to roll the engine over another 180 degrees to find the mark.

The other thing you will need is a tachometer to find 3000 rpm.

This will give you the max running advance when set which is the most important.

 

[aogrady]

If your stuck time it dynamically at about 30 degrees before TCD at around 3000 rpm, dynamic timing is a better option that static.

Will will need either a strobe with an advance function or a timing scale on the case, use the TCD mark for number one cylinder, if you not sure which one it is take the plug out on number 1 and turn engine over by hand till the piston is at the top of its stroke, I use a socket extender when Ive done this, then see which mark is in line with the case. You may need to roll the engine over another 180 degrees to find the mark.

The other thing you will need is a tachometer to find 3000 rpm. This will give you the max running advance when set which is the most important.

Hi

Thank m8!, have a strobe light, but not got degrees on my pulley, no rev counter either...........
I think i saw on vw resource a therory on how to work out the degree settings using pye and the pulley radious. Just need a rev counter now..... :roll:

So 30 degrees before TDC is to the left of the (assuming) TDC notch on the pully, and IIRC, there should be a little notch on the dizzy and number one on TDC should point to it?

Alistair

 

[Padwah]

I've just fitted a vac advance distributor from Just Kamper this weekend and statically timed it to 7.5 BTDC using a strobe light, the mark for 7.5, or 30, degrees BTDC should be to the right of TDC when you're looking at the pulley, so when you set the timing the notch for TDC should move to the left of the split in the crank case and the notch for 7.5, or 30, degrees should line up with the split. Make sure that when you set the timing that you've removed the vac hose from the dissy to the carb and that you've plugged the hole in he carb.

 

[noddy]

Padwah

You only disconnect the vac hose if your timing statically, if you are timing dynamically the hose needs to be attached other wise the distributor wont advance, no manifold vacuum = no advance, assuming its a SVA dissy.

 

[Padwah]

Sorry, you're right was a bit pissed when I posted that last night!

 

[matt-me]

How do you know if your dizzy is vacuum advance only or dual vacuum advance? I have a second hand dizzy and it seems to run best at 10 degrees btdc statically.

Thanks

 

[noddy]

Matt

Easiest way to tell is the size of the vacuum can the larger flatter cans are the SVA type. (see http://www.thesamba.com/vw/classifieds/detail.php?id=767021" onclick="window.open(this.href);return false.

 

[matt-me]

Thanks Noddy. Mine doesn't look like that, must be SVDA.

Al (long story)