Darkbound

I just want to update the thread and say that I have finally managed to fix the problem. The knock is no more. Althought no one could say for certain "there, this is what caused the knock", my suspicions go to Cylinder #2. The reasons are that both sets of pistons that I had in the engine (the one before my first rebuild and the one that I put in on the first rebuild) had piston #2 wearing much more than the others. Cyl #2 was a bit worn out (but still within specs!) at TDC. Like I said, I'd bet that the problem was in cyl #2. Sooooo, about a month ago I did a second r

They were not, anyway I took everything today to a machine shop to get it measured. Everything is perfect, bores are perfect, rods are also perfect not twist/stretched, perfectly balanced within 1g of each other, they said that the pistons (aside from these scratch marks) are also good, we still cant find any explanation for my knocking problem. Crankshaft is also perfect.... Im getting 1mm oversize pistons along with forged rods and r36 rod bearings, and to hell with it.

Does this sound like your knock?

This side (this is not my piston, random image from google)

Its the "smaller" side

Hey guys, I finally took my engine apart to hunt for the culprit of the knocking noise that I had, second time now. I have very strange scratch markings on my pistons, ALL of them have them to a different degree, but same pattern. These pistons were installed in the car 10k miles ago they were taken from another vr6 engine. My old pistons do NOT have these scratches. What could be the reason for such scratches? There is nothing that I can see on the cylinder walls/bottom that could haev caused such pattern, I am taking everything to am achine shop in tuesday, but still t

So I ordered one half shell with part number 03H 105 701 EGLB and I can confirm that these are indeed the R36 coated bearings. You need 6x 03H 105 701 EGLB and 6x 03H 105 701 EROT.

Hey guys, I've been looking around a lot about these bearings. I am a little confused with all the different colors that they have, reds, yellows, blacks and whatsoever. I want to get the black coated R36 bearings to upgrade my bearings on my VR6 2.8. I know that they fit, I just cant find the god damn part number! All I found out so far was the following number: 03H 105 701D When I went to the shop and we searched for this number, nothing came up. We had to search for 03H 105 701DROT and 03H 105 701DGLB for RED and YELLOW bearings (whatever that means, please explain!!!),

I forgot to respond that I found the problem. The problem was indeed that the hose was not fixated on the pump, so I am guessing it was just floating above the fuel and sucking air, once I attached it on the side of the pump where motorrob showed, it stopped whining.

Allright, it is now confirmed, piston #2 is worn more than the allowed limit. They should be 80.925 - 80.965 mm, all pistons are 80.94 mm except piston #2 which is 80.89 mm measured by two different people. There is no apparant damage of any kind on the pistons, just the graphite(?) skirts seems a bit more worn on one side.... one of the guys that measured it, said that most likely I have elliptical cylinder wall on #2 cylinder and this is what is wearing the piston. It would also explain why the knock is still there, but I have no loss of compression/performance, its not burning oil, nothing.

So I just got my parts back and got the play measured, it really is there but its negligible... had all my old parts measured, crankshaft turned out ot be perfect, pistons are ok (I think, still looking for the correct dimensions for BDE pistons), the only problematic thing is that there is significant wear on the bearings, and the caps of the conrods dont align perfectly with their respective conrods, when you slide your finger on the inside you can feel a notch at the place where the cap and the conrod connects.... still looking.... gonna drop the pan next week and see how are my new bearing

Thanks for the effort! But thats still not what I am looking for, these are the radial and axial clearances between the rods and the crankshaft, I want to measure the rods themselves, I couldnt find these dimensions in the bentley and I have tried searching in Google

Hi dubvr691! This is not what I am looking for, I am suspecting that I have a play in my wrist pins (I have a knock) and I want to measure them, what I am looking for is this: Dimension for the small end of the conrod Dimension for the big end of the conrod Dimension of the piston wrist pin And big end center to small end center on the conrod itself

Hey guys, anyone knows what are the dimensions for the whole on the piston, where the piston pin goes? I also needto know what are the dimensions for the wrist pin itself, and for the conrods, small/big end and center to center, can't find that info in the Bentley manual.... Thanks

P.s. i said that it makes sense to be piston pin or possibly beqring, because i finally found logic about the knock skipping a revolution. 1 revolution there are open valves and no compression in the cylnder 2nd rev closed valves and pressure. One of these scenarious causes the knock. This explains why its half the crank rpm but it comes from the bottom. So its not in the alve train. Some guy told me that piston wrist pin knock occurs only during its "work stroke" so it really makes sense if this is true.