Engine Noise At Idle

Ok, so i had my engine rebuilt a few months ago. After the rebuild, i started to hear a knock noise at idle, only idle or slightly above. I had about 100 miles on the engine and i took it out and sent it back to the builder. They said they found nothing wrong with any of the bearings. I made them replace them all anyways on my dollar. I put the whole motor back together and sure enough, still has a knocking noise. I know it is not a lifter, too muffled for that. Most of the time, rods knock at higher rpm when they start to go, or at least knock at more then an idle. Anyways, I took the motor all apart again today and i found a few things. The tensioner has a pin that the spring goes around. It has play in it and i think at idle, the pin is banging around as the slop in the chain is moving the tensioner arm. I also happen to notice that i am starting to get some metal transfer on the cam thrust plate. Has, anyone had any of these kinds of problems before. It is a new cam, and i made sure it isn't binding. I am thinking that my builder just used a cheap tensioner. Any ideas on this would be great.

I also found some play in the synchronizer bushing the is pushed into the timing cover. When i install the synchro into the cover, i am able to move the shaft up and down in the housing makeing a fairly large gap between the drive gear and the bushing. Could the synchro shaft be bouning up and down at an idle?

The wear on the cam thrust plate is not unusual for an SC but it's not good and both parts should be replaced. It would also appear that the spacer was put on backwards because the part # should face the timing gear, not the thrust plate. However, this may not be your problem as lubrication to the thrust plate is marginal on the 3.8L engine. SSM offers a Torrington bearing thrust plate for $180 but that seems a little steep to me. I modify the spacer and thrust plate for improved oiling on all my motors.

As for the tensioner, it may be cheap but it's the only one available. Melling, Sealed Power, and Cloyes all use the same part, they just box it up different. I don't think that was your problem. When the tensioner adjusts out, it does not adjust back in very easily.

I would be much more interested in knowing your oil pressure, particularly at idle.

well, when the tensioner was installed, It does srping tight and lock so it can not go in again without releasing the one way puck. But when i pressed on the swing arm and tried to push it in I could see the pin that the puck slides on move up and down. At the hing point for the swing arm, there is that half round ball that is supposed to keep the pin in place and i noticed it moving as i pressed on the swing arm. I am sorry if this is hard to understand, my words may not be right. Anyway, i can see several shinny marks on the pin from it moving an 1/8" or so while it is running. I will install another new one just incase when i put the motor back together. I agree that it wold be hard for the noise that i had to come from this pin moving around, but i have looked at EVERYTHING else. As far as the thrust plate. There are marks on both sides. I switched it the last time i had it out to see if that made the noise go away.