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Darkbound

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About Darkbound

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    Bulgaria
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    VR6
  1. 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... Shouldnt this be happening if there is problem with the cylinder walls? (I was not ther when they were measured during the rebuilt, they just told me that they are ok, supposedly they were checked by a specialist, but I can't be 100% sure that they really measured them correctly)
  2. 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 bearings and if I Will find anything that may cause a knock..
  3. Piston Pin and Conrod dimensions?

    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
  4. Piston Pin and Conrod dimensions?

    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
  5. 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
  6. 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.
  7. Sometimes, but the sound definitely loses its strenght when its warm. I gave my old parts to a mechanic to inspect them and he said that he found play in the piston pins. I am almost 100% ready to agree that this is the source of the knock, it makes sense. What i cant figure out is why after tbe rebuild i still have it on the same cylinder? I got a whole set of rods and pistons from another engine its extremly unlikely that thet have the exact same issue and the bad pin will fall into the same cylinder. There is some oyher underlying issue somewhere and the knock is nusy byproduct. Thats what i think.. Also worth mentioning that when we did the rebuild not a single bearing came out with its cap (rods) they all seem out of place when placed on the caps they stayed on the crankshaft. I cant find any information what this means. Also there were worn our bearings and thry have only 10k miles on them (old owner did a rebuild shortly before i bought the car) These beaings are the onea that i think are most worn out
  8. 12v vr6

    Let me ask my crystal ball, it should know what you want to use them for....
  9. As for the oil, I am using the best oil that I could find, currently its 100% synthetic 5w30 bardahl with fullerine additive, the engine sounds amazin when the knock goes away, so silent... after the rebuilt I briefly used 10w40 durinjg the break in period it had almost no effect on the knock.
  10. Thanks! The problem is that the engine was rebuilt twice already, and it still has it, once from the previous owner, he spun a bearing on Cylinder 2, when I bought the car it had the knock, then I rebuilt it (didnt have it spun, just did it cuz of the knock) and its STILL there..... the only thing that I notice is that the old bearings that I removed (new when previous owner did rebuilt) haev no more than 10k miles on them, and there were a few bearings that were almost worn out, not a single bearing came out with its cap, and not a single bearing fits and clicks into its cap, they stayed on the crankshaft. The patterns on the worn bearings points to insufficient oil on the specific cylinder, but i dont know which cylinder that bearing came from... The only thing that I can think of is that, some oil gallery probably for cyl 2 got clogged and cant provide sufficient oil. And somehow it stayed clogged after 2 rebuilts.. gonna drop the pan after 2 weeks and inspect the bearings..
  11. Is no one able to even make a guess? I am really out of options at this point, I really like the car and I want to start working on improving performance and looks but I just cant move on to do anything until I sort this shitty knock first as I dont know what it is from The things I know for certain: - When listening on the top of the head, the knock is most noticeable above cylinder #2, confirmed with stethoscope - When listening at the oil pan, the knock is again most noticeable bellow cylinder #2, riiight next to the oil temp/level(?) sensor, the sound is much more clear and louder than from above, again stethoscope - The knock occurs once for every 2 revolutions of the crank, confirmed at idle 680 RPM on crank, 340 knocks, confirmed also at 1000 RPM, 500 knocks and at 1200 RPM 600 knocks -- The previous owner had a spun bearing on cylinder 2, he did a rebuild, changed crankshaft and only conrod for cylinder 2 new conrod/main beaerings and everything else that has to be changed, I also changed crankshaft and ALL conrods/pistons with all new bearings... - Last night I played a bit with my old crankshaft/conrods/pistons, I assembled them and there is no up/down play at all on the piston pins, axial (side) play on the conrods is between 0.15mm and 0.20 mm, wear limit is 0.40mm si thats not it either Yes the knock is much louder and it sounds like u r right next to it when you are listening bellow the oil pan, but it doesnt make a sense, how could a knock coming from the crankshaft area will skip a crank and do it only once every 2 cranks? If the knock was from piston pin/bearing I would expect to get at least 2 knocks per revolution, or 1360 knocks per 680 rpm, instead they are 4 times less. The sound looses its "power" when the engine is fully hot, the sound also sometimes goes away if I let it idle for a couple of minutes.. Any guesses, crystal balls and whatsoever are welcome if they can provide at least a little logic More recordings of the knock:
  12. Also you may notice that the knocking in the new video has much lower frequency, the first video was from before the rebuilt. I analysed the sound and determined that now the knock is occuring at exactly half of the crank RPM. So for 2 crank rotations, I get one knock
  13. So I tried unplugging the coils one by one, and there was a difference in the knocking when I was unplugging cylinder 1 and 2, this is where I think the knock is the most loud. When I unplug cyl 1 it gets quieter, when I unplug cyl 2 it gets more violent
  14. Does anyone know what is the part number for the intermediate shaft bearings, and what should be the sizes on the shaft and the block? I looked everywhere I can and cant find that information, also the Bentley manual has no information whatsoever on that shaft....
  15. Forgot to mention there are no error codes at all.
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