Two topics are discussed in this treatise -
Regarding finding Top Dead Center, the procedure (Step #6, Timing) reads -
Rob elaborates -
There is usually a few degrees of rotation which still feels like TDC - use the centre of this 'dead zone' as TDC. Can be cross checked against any existing marks on the pulley. If the pulley has a single mark to the left, it should be 7mm to the left (this indicates it's a 5 degree ATDC pulley which was used on the double vacuum dizzies). So mark your TDC as described above.
With the engine at TDC on #1 or #3, the key in the crank pulley is at 9pm. Helps confirm the piston is at the top, rather than the bottom. The 9 o'clock key position will just give you an indication you're in the ball park -- you still need the pencil to accurately find the "null point" -- exact TDC.
If it's a single notch just about on the split in the crankcase, then it's a 0 degree TDC pulley, and you can use that mark (it was used on some mid-late 60s 1500s - usually with the semi-auto trans), and mark your 7.5 degree BTDC 11mm to the right.
If the pulley has three marks, the left one should line up as the TDC mark. The two right ones are 7.5 degrees BTDC and 10 degrees BTDC (10 BTDC was used on the 1200s).
The procedure continues -
While you're at it, rotate the pulley 180 degrees and paint a mark on the pulley there. You will use this point when you adjust the valves.
From the TDC mark, also measure 11mm to the right on the rim of the crankshaft pulley. This is 7.5 degrees BTDC; mark this point also with white paint. This is the point at which the centrifugal advance distributor (009) is timed, so it is very important that you mark it as precisely as you can.
Rob elaborates -
Remembering that 009s vary and if set to the correct 28-30 degrees BTDC at 3000+RPM, it could result in static timing of something in the range of 5-8 degrees BTDC).
The procedure continues -
From the TDC mark, measure 46.5 mm to the right on the rim of the crankshaft pulley. This is 30 degrees BTDC; mark this point also with white paint. This is the maximum advance point at 3500 rpm.
There are at least six different VW pulleys and four of them in common use -- and they all fit on every crankshaft!
Following are the four types of pulleys in common use on aircooled VWs -
You have to find TDC for #1 cylinder, then look at the notches to confirm what you have.
Turn the pulley so the notches/dimple/whatever is roughly at the top. Remove #1 plug (right front cylinder) and place a long pencil in the hole (nothing metal please - the plug threads could get damaged) and feel for the top of the piston. Rock the engine back and forward until you find the highest point, and this will be over several degrees, so you want the "null" point in the middle.
Now look at the pulley. Dimple near the split in the crankcase? If so you have a dimple TDC and can check you have a notch to the right - that'll be 7.5 degrees BTDC.
One notch to the left? - then it's a 5-degree ATDC notch and you need to make a mark 11mm to the right for TDC or 18mm to the right for 7.5 degrees BTDC.
Both notches to the right? then it's a 7.5-degree and 10-degree BTDC pulley.
One notch about on the split and two to the right - then it's a TDC, 7.5-degree and 10-degree BTDC pulley.
Now you know what you've got, you can time it according to the distributor you have (009, single vacuum, double vacuum or SVDA) - see the tune-up procedures on our main web site - all distributor types are covered.
Incidentally, if you have a 009 distributor, it must be set at 28-32 degrees at 3000 rpm - you can't accurately set the 009 distributor to an idle setting - they vary too much (cheap build). 30 degrees is 46.5mm to the right of TDC - make a mark.
Disclaimer stuff: Rob and Dave have prepared this information from their own experiences. We have not assumed any specialised mechanical knowledge, but we DO assume that anyone using this information has at least some basic mechanical ability.
We hope you find this information useful, but we don't take any responsibility for anything which happens to you, other people, your VW or any other property or goods resulting from your use of this material.
Feel free to print off any of this information for your own use. If you intend to link this material to another site, reprint it, or in any other way redistribute it, please leave the information complete, including this disclaimer section, and provide a link to this Web site.
Last revised 4 May 2004.
