wojzal

I have attempted to replace a timing components (chains, slides, tensioner, etc) on CPNB engine. I followed all steps from the Audi Workshop manual. I locked the crankshaft at TDC position with locking pin, and locked camshafts with locking pins as well at TDC. After replacement of all parts, and removing all pins, the engine turns smoothly. After several turns the timing appears to be perfectly aligned. However, when it reaches the TDC position at each turn, the engine becomes slightly stuck, and to turn it I need to apply more force to skip the TDC position. After that the engine turns smoothly. Is this a normal behavior?

wojzal

I'm going to answer my own question again. I found out elsewhere, that it is normal to feel resistance when turning crankshaft from TDC position.

MarkDoronin

If it's not too late, I'd like to know the reason if you did find it.

'10Q7TDI_Prestige'

Unless you've also removed the valves/heads from the pistons, there's this thing called compression that occurs at TDC for each piston stroke; on a TDI motor it is a relatively high compression ratio, since it is a compression-ignition type engine, where the compression generated heat actually ignites the fuel, etc. Watch some videos on how shops replace the timing chains/sprockets/components; you generally won't ever see them 'turning the engine' after since that is something they would do prior to disassembly in order to ensure the engine isn't locked up/damaged internally prior to swapping out all those expensive parts for new, etc.

They do most definitely examine all of the timing parts/guides, tensioners, etc., they take off for damage and look for any missing pieces of the guides or other parts that may have collected at the bottom, etc.

Good luck!