Good day to you all! M60b30 Alusil block with 60K miles. Heads and oil pump with 160K miles. Fresh 10w40 oil change/10w30 previously. I have checked the oil pump--there were no bolts missing from either the pump-body or the pump mounts, but the chain-drive was floppy and some body-bolts were slightly loose.
There is a noise apparent when engine is hot. It seems to come from the passenger bank of cylinders. It is a mid-pitched rattle when revved to the 2K-3K range. It is not like a can of marbles--the sound is more controlled-if that makes sense. There is also a rhythmic tap-tap-tap with a similar pitch at idle. Also at idle it almost sounds like there is a squeaky wagon-wheel in there.
I used a dowel to try to pinpoint the source. When I place the dowel on any of the forward-most valve cover nuts, the sound is louder than any other location. Since I tightened the oil pump chain, the sound became less "chaotic" --assuming a more predictable cadence. This leads me to believe that the lower timing chain and the oil pump chain were rattling around with different frequency causing all sorts of noise, but now it is only the lower timing chain. Does it sound like I am on the right track here?
What is my recourse? Do you think it might be the tensioner on the pass side of the block? Is this something I can merely remove and replace, or does it require priming and/or aligning. --Yes I would like it to be an easy fix
Does anyone have any thoughts or suggestions as to what might be going on here if I have deduced incorrectly?
Thank you all in advance for any helpful advice you may be able to offer.
This is a kick-ass forum, and I am truly sorry that I have not posted in nearly two years. It has been a very interesting interim.