Club 80-90 Forums

Hi I have an AHU 1.9 TDI engine and I'm looking to see if anyone has knowledge of the crankcase position for TDC on the pulley side?

I don't have the gearbox to line up the flywheel on this engine plus this engine came without a cambelt on it, someone before me whipped off the fuel pump!

anyone with advice would be appreciated.

im aware there is a small dot on the crank pulley which locates into the raised dot on the crankshaft cog, does this have any relevance to TDC ?

Pretty sure on most crank pulleys there is a mark which corresponds to a mark on a surrounding bit of plastic/metal trim. This will never be 100% accurate though as 1-2mm out at the pulley would scale up to quite a lot at the flywheel

I cut down a glow plug and fitted a length of clear tube to it, fitted it to number 1 cylinder then filled a loop of the tube with coloured liquid to use as manometer, used a protractor on the crank pulley and rotated a few degrees each way of where I thought tdc was and the watched the liquid in the tube to confirm tdc.

I'm sure there’s a video on youtube how to do it

I've removed the sump for only visual confirmation - using the flywheel I looked for TDC markings then worked out from looking at the bolts on the fly wheel where 12oclock would sit and turned the crank to the presumed position. I checked the underside of the crank and the two middle pistons were down and the outer pistons were up in a vertical position.

then fitted the cambelt and cranked the engine clockwise using a leaver bar with 19mm socket, see if anything would collide...........seems fine.......... !

This is how it would be done with the VW tool 2068A.

You can do it without any tools.

If you have the sump off, get the engine visibly near TDC like you said. Then with no cam belt on, turn the engine very gently by hand back and forth either side of TDC. Just at TDC you will feel the engine"relax" for a tiny amount of rotation then tighten up again. This bit is where you're not sliding the piston rings up or down the bore. Mark the extent of this tiny "relaxed" bit on the pulley against a fixed point on the engine as accurately as you can. TDC is smack in the middle of the marks. If your piston ring grooves are badly worn the marks will be further apart than if the grooves are nice and tight.

This is subtle but works really well to better than 1 degree.

hi Colin

I agree with your post, and yes it was definitely like the engine relaxed at this point. now the belt is on and I've turned the engine over using a 19mm socket and bar this resulted without any obstruction from the valves. I believe it may be ok otherwise..........ouch

I'm having a similar problem timing up a 1z I have on an engine stand, I've no fwd box to get the flywheel marks from. I do have an A4 afn box laying about could this be used? Sorry to jump on you're thread.
Thanks

Jc

hi jc

no not at all I believe im done and up and running just need to fit the engine asap.

if you follow the advice from colin about feeling the crank relaxing, you really can feel it. In addition if you can drop the sump and view the crank shaft from underside, hopefully the two centre pistons will be down and the outer pistons up. time your pump up in position. make sure the cam shaft is locked in the timing position at the rear with a flat metal bar. Also keep your cam pulley loose on its shaft at the other end. Put the cambelt on from crankshaft and work it around anticlockwise. then do the necessary tensioner etc...

remembering to tighten up the camshaft nut before taking off the pump lock and cam lock ! Then gently turn the engine over using a 19mm socket on a long bar at the crank shaft, turning clockwise direction very slowly to check if any pistons hit a valve. you'll know if one does, start all over again!

Thanks, I think I'm going to put the afn flywheel and gear box on just to satisfy my paranoia, for all the time it will take.