Jack3m

The new pistons came with only dots on one side all were oriented to the front of the engine on assembly. But we got at least 50 miles before any sound like this and the point of deceleration starting the noise is just bugging the heck out of me. Very frustrated, no idea what to do even by tearing it down without a known issue to look for, I expect to see the nuts on the con rods have been hitting again, but will be hard to tell if new or old as I didn't do anything to the marks before re-assembly.

Nope did not move at all, the noise is definitely down in deep. I am wondering if a con rod is hitting the case again....but why?

I am the Dad in this mess. I am clueless at this point. It is not valve train, DOHC and solids. If we have any professionals here, I am in need big time, Something very strange is causing this problem. I am going to throw out all sorts of information here, possibly not in order. I had 10 years front line in dealerships, knew my stuff, did it all, and was the problem child fixer. I worked on Nissans, but 1980 was my last year in the profession. Initial sound was exactly like a rod knock. Sounded like RF cyl. Engine running well, no missing, no other unusual sounds. No signs of head gasket leak. Oil pressure after rebuild 100 psi by gauge at the sending unit port. Engine rebuild consisted of crank kit and pistons and rings....pistons had new Jesus clips. This went fine for a little after the rebuild then it had a ticking noise that turned out to be the timing had slipped on one side. From one of the posts I am now certain the tensioner is weak, it is pretty easy to push and can do quickly. BUT now with new noise that sounds similar to a rod knock ,but not if you know what I mean and running, the noise is behind the tensioner, either oil pump (new) or something at rods. Now, on teardown, it needed bearings really, really badly, one of the worst I have even seen. There were signs of the nuts on the con rods hitting the inside of the case in all cyls. Not really bad, just noticed and thought the new bearings and crank would cure the issue. Con rods at torque were 0.00015, Mains at just tightened, no torque was 0.0001~0.000125. Also on initial tear down it looked like one cylinder had (at least at one time) had a lockwasher go through it. We did not find anything that could have caused that. The auto had not been recently worked on. OF NOTE Both times this car started making this noise was on a deceleration to make a turn. Interestingly with all this, the valves have apparently not been hit as they are still okay and the engine runs fine. Oh ya, today when he first started it today, until the oil pressure built up, the knocking was not there. Oil pressure made it show and very, very loud. NOTE EDIT: I don't know what you mean with HLA. I am sure I will slap my forehead, but right now it is already pretty sore.