M50 engine noise (more)

[jhansen]

Hi, the car is late 95 production date, I did some head work - gaskets valve stems etc. - recently (thanx for the good DIY on this page). However I now have this rattle-y/gurgle noise coming from the top of the engine while deccel and is more pronounced at 1600-2000rpm. It seems to disappear when it goes below that, sometimes you can hear it stationary and rev to 3500rpm but not always. It seems to be coming form the intake side right over the vanos. I was checking on things yesterday and when I pulled the valve cover I noticed the primary chain (crank to exhaust cam) had some slack (about 1/2in from the guide) opposite side of the tensioner. What's with that? Logic says it shouldn't be there but I am not 100% sure. I did a few complete turns manually and it went away. Tensioner is one piece (with out the bolt cap), it is not binding and piston moves freely. I am thinking maybe piston is worn out and does not hold oil under load. Corretc me if I am wrong? Another thing I've noticed, while stationary at idle and I am taking off with moderate acceleration it will pop through the intake (backfire maybe), it will do it every now and then not often.
Timing has been checked a few times and is spot on. My thinking is the chain slop messes up the timing making the car backfire through the intake. Lower Tensioner on the car has the flat piston. Can I retrofit the tensioner with the "forked" piston as described in the DIYs? I was looking for a slot in the guide rail but could not see one. Any ideas regarding the above mentioned problem are welcome. Thnx and sorry for the long post.

[coolbear1]

Maybe noise from the vanos itsself, I have never experienced it with my m50 engine, but I have seen it come up on this forum from time to time. Try a forum search on noisy vanos and see if any of it sounds familiar.