Been trying to work out why when ever anyone says number one cylinder firing point is at 5 o'clock I think of mine being at 2. After getting carb throttle bushes properly done in a German Solex 34 pict 3 after breaking down again........ I got myself a tacho and Gunsen timing light with advance feature. Went out to play starting at scratch and got totally confused by timing notches on crank pulley, dizzy notch and rotor arm position and valve positions at supposed TDC. Have taken pics and hope to get to the bottom of this once and for all. (Not a New Year res obvs!!)
It depends on the distributor where the No1 notch is. They are often where yours is on later distributors. More importantly, you have the vac advance pipe connected to the wrong port on the carburettor where you have it will cause full vac advance at idle, it should be connected to the port on the left side of the carburettor where there is no vacuum at idle. Someone has been cutting new marks on the pulley, but the centre of the recessed dimple on the outer rim of the pulley is the TDC mark. The V notch to the right of the TDC mark on the inner rim is probably 7.5deg BTDC. Check the dimension from TDC it may have had the wrong pulley fitted with a 10deg BTDC mark.
Hello Bigherb, thanks for that, will get a pic of dizzy numbers, it is a VW one. The left port on the carb was quiet a small inner diameter compared to the front one, which appeared to be the expected size. I did chat to the chap at the carb hospital in Rochford when they replaced throttle spindle and bushes, he said it was more likely to be the front one to use. Any other help most welcome though.
It may also be that someone in the past has put the dissy driveshaft back in the wrong position - not unknown. In a perfect world, the dissy drive "slot" should be as in your Haynes pic when the engine's at TDC on the compression stroke for no 1 cylinder (both valves rattly). The rotor will (or should) then point to no 1 plug lead.
iBest i remember my rotor arm is as per Davipons pictures above pointing at the position for barrel number one at TDC , however the picture from the book immediatly above suggests thats the position for barrel 2 , so i think - thats what your pointing out Bigherb , this is the details on my distributor if it clarifies anything
I have not had a type 1 for a while but isn't your vacuum pipe to the distributor on the wrong port on the carb ? I think it should be on the one thats blanked off on the left
Here's my "aide memoire" kept in the engine compartment of my AS 1600 engine. Note the "slot" in the distributor drive shaft is towards the rear of the vehicle, parallel to the bumper. Whatever distributor you have, when the engine is in the above position and the timing mark where it should be, the rotor should point to plug number one VW produced pulleys with a large variety of timing marks for different engines, and for different local emission/fuel quality requirements. It follows that a 40 year old engine may not have the correct pulley, probably having been rebuilt more than once. Never trust pulley marks on a new-to-you engine. Find and mark the TRUE TDC. Ignore the "pencil-through-the-plughole" method, it's inaccurate. Mash out the insides of a spark plug and insert a length of threaded rod through it secured by a nut on either side. Adjust this so that about 10mm protrudes further into the cylinder than a spark plug would. Insert this into the plug hole and turn the engine by hand until the piston jams against the rod. Draw a temporary mark on the pulley where it lines up with the crankcase centre. Turn the engine the other way until the piston again jams against the rod and again mark the pulley. True TDC lies EXACTLY halfway between the 2 marks. I've filed a large new notch on my pulley and scratched "TDC" on it for future reference. You now have a true TDC you can rely on for the life of the engine. ----------------- To time for a vacuum advance distributor…. Get the engine running and warm at whatever timing works. Disconnect and plug the vacuum tube. Set the timing so that maximum advance when revved hard is 28 degrees BTDC. I’ve treated myself to an adjustable strobe light for £30 – just dial up 28 degrees and turn the distributor until your new TRUE TDC mark lines up with the crankcase centre. Should run like a dream now, mine does
Hello 3901Mick, as said above "The left port on the carb was quiet a small inner diameter compared to the front one, which appeared to be the expected size. I did chat to the chap at the carb hospital in Rochford when they replaced throttle spindle and bushes, he said it was more likely to be the front one to use. Any other help most welcome though." Cheers David
That's really Helpful, guess I have an AS engine then? The slot you mention for the distributor drive shaft, assume it's the view inside engine with distributor removed? David
All my previous solex carbs, whether repro or original have been set up with the vacuum hose to the left but this body is slightly different and the internal diameter very much smaller on this ones left tube hence the question, will change over once timing set up. Will get a pic of distributor later today. Thanks for info chaps. David
The one you want for the distributor advance will /should not have vacuum if you pull it off the distributor and the engine is warmed up and idling. There may be a second vacuum feed which will suck at idle . This is a vacuum retard signal that goes to a dual vacuum distributor. Used in the USA to make idle emissions look good . If you have one stick a bolt in the hose. Not needed to make the engine run well. The proper vacuum advance signal is zero at idle, increases at part throttle and collapses to zero at wide open throttle.. hence no vacuum at idle. This gives better torque for acceleration in a bus, compared with a Beetle where it leaps forward like an (overweight ) gazelle equipped with a centrifugal (speed related) only ignition advance on the 009 distributor. The hippopotamus bus needs a bit of a boot up the backside from extra timing advance...hence the SVDA aka 205 distributor.
So if engine idling stick a thumb over either with the other blocked to see if suction present? Then try with engine running at higher revs and go with the results.
Just put the hoses where they are supposed to go. The one on the side is for vacuum advance, the one on the front is for a the air filter pre heat flap.
