TDC - Cant seem to get Rotor aiming for the notch...

Hello there - hoping someone might help give some advice. Just trying to sort the valve clearances as have no idea when they were last done

Rotor



pulley marks


rotor position odd - but think am at TDC



Are these standard pushrods or steel?


Thanks!

Andy

 

Your rotor will be in the right place if the engine is at TDC. The notch is a guide for people with the distributor drive gear that is dropped in to place in one out of 22 possible alignments relative to the crank that matches the location shown in the service manual.
The engine will run perfectly in the other 21 alignments.
The right place is where it happens to point. The No1 lead goes into the distributor cap nearest where the rotor happens to be at TDC.

More of an issue for you : A single notch pulley may be marked for TDC or 10 BTDC or 7.5BTDC or 5ATDC dependent on which engine it came off ...
So you must use the pencil in No1 cylinder trick to find TDC as the pulley may not be what you expect. And the difference is enough to trash the engine.

Set up the pushrods for stock aluminium as if you get it wrong and set zero clearance for steel you will end up with open valves with a hot engine and a loss of power and a possible trashing.

Or undo the nuts holding the rocker arm on and pull out a pushrod and try it with a magnet away from the steel tips..

 

Really useful info. I have exactly the same situation as Andy on my buggy. I wondered why the rotor didn't point at the notch when at TDC on #1 - now I know. Thank you.

 

Looking at your pulley I can see the little v notches on the rear side as you look at it. There should be a dimple on the side nearest you. Difficult to see from here. On my pulley the dimple and v notch parallel to it are for TDC. The v notch to the right of these as you look at it is my 7.5 btdc. My rotor arm points to roughly 1 o'clock but with the 009 I think it's roughly the 4 o'clock position.

 

Which looking at your pictures is about right.

 

I've never had much luck with the pencil trick. There is an aussie youtube vid of a chap turning the pulley back n forth while watching the valves on 1 and 2 open n close to ascertain TDC. If I can find it I'll post the link.

 

This is for the svda dissy but principle the same

 

Snap!

 

ah okay thats useful to know I will check that shortly

There are 2 faint notches (looks like they were done by hand file or similar)
and using the video link above I was able to observe no movement on the cylinder 1.

Some great advice here though so thanks!

 

interestingly this is on my buggy too...

 

not sure the pencil trick gives me any more certainty as such than the video...

 

I find a more accurate way to determine TDC is the longer spark plug method. Get an old spark plug and mash the bit in the middle out, then carefully weld a bit of bar or something in the middle, so that the overall length is slightly longer than original. Set the pulley so the marks are pointing to the left, and screw the plug in finger tight. Slowly turn the engine by hand until you feel the piston touch the plug. Put a mark on the pulley in line with the case join. Then slowly turn the pulley the other way till it touches the plug again, put another Mark on pulley. Then measure half way between the two marks to get actual TDC.

Obviously, make sure the plug tool tip is symmetrical and smooth, and that you don't damage the threads when welding it.

 

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.

 

This started as a five minute job.... Can't believe it's now involving fabricating tools. Lol.. I give up.

 

I think the one on my buggy is 6700.

 

I used the video method. Worked fer me. Didn't need to fabricate owt

 

You don't need to worry too much about the accuracy of Tdc marks if your just doing the valves, you will see when they are both closed, and you can feel the engine is on the rock. You will want to time it at some point though..

 

So i have given up - defeated...

didnt want to mess this up so going to take it to the experts. so in the meantime I might as well buy a new pully with marks on it.. any reccomendations?