would I be wrong in assuming that since the vw 1.6td are very similar to the 2.0td as far as bore size? i believe stock bore is 76.5mm, and all the research Ive done suggests that using 79.5mm pistons from an aaz are out of the question. That being said, whats a safe bore size on either motor? 1mm over 77.5mm? any experience or insight would be greatly appreciated.thanks.
If I do another 1.6 it will have aaz pistons in it. IIRC the vw 1.7l diesel is just that. My 1.6 that ate a precup was .050" over and it still has around 3/16" of cylinder wall left. I do not think in a performance application that it would last, and I will not do it with a fresh block, but other than that I think you can bore them a lot. Take it to the machinist and have it sonic tested to be sure that the cyl walls have enough meat if you are really concerned.
You are correct, the 1.6 and 2.0 have exactly the same size pistons. It is also true that 79.5 mm pistons are too large. I researched installing 79.5 mm pistons into my 2.0. I had the walls sonic tested, but there just isn't enough material there. 77.5 mm should be 100% fine and will take you to 2.028 L, a 2.6% increase over stock.
If you really want to run those 79.5 mm or larger pistons, you could consider running a gas block. One down side is that it won't have 12 mm head bolts like the 2.0TD. Another is that the 2.0 head you have most likely has mechanical lifters, but just about any gas block you find will be for hydraulic lifter heads. You may have to do something with the oil feed and return ports like they do on the 1.6 engines.
is there any possible way to sleeve the 2.0td? Dry Cylinder Sleeve; Finish: Semi; Outer Diameter (mm): 79.560; Flange Ø (mm): 82.500; Follow installation instructions:; Length (mm): 142.000; Width (mm): 4.500
those are sleeves for the vw 2.4l ? just a thought
That might work, I don't really know. The VW/Volvo 2.4 is a much closer relative to the 2.0 than the 1.6 is.