M62 Cam timing graph

[CapeX5]

Thanks Spanker, would I actually be seeing "vacuum" in those spots as opposed to pressure? I guess if there is a problem, I would see spikes of pressure as the piston came up and there was no sealing with the valve. Thinking out loud there. Also, I have a mechanic stethoscope that I have used extensively on the engine. The problem is that the aluminum heads/valve covers etc all resonate and throw the noise all over the place. The common denominator is that it seems to be coming from the front of the bank 2 valve cover. There are no abrasion/wear marks anywhere on the valve or timing covers. The only other moving part right there is the VANOS and the chain/sprockets/tensioner for the exhaust cam. Those parts all seem good and I have replaced orings on the tensioner and the rubbing blocks. The tensioner is holding lots of oil and is very difficult to compress when I am dismantling to do the timing work. Again, I am back to the VANOS transmission. Parts arriving today, will be tearing it down again after the misc tests first.

Originally Posted by Spanker

You can tap from the back of the intake manifold (on CCV). I also believe there is another tap on the right side of the throttle blade.

You would look for a wildly fluctuating reading rather than a smooth one.

Here is another trick. Take a long screw driver and place the tip on top of the metal portion of Bank 2 valve cover...... place your ear on the end of the screw driver and listen for the origin of the sound. Listen in the vicinity of each cylinder. If it is the valves, you will absolutely hear it loudly in that area.

Check the for ECM error codes. Sometimes it can tell you if there is problem with vacuum. Not sure x5 has that kind of monitoring. My 2007 vette once broke a valve spring and the manifold pressure guage spoke to my computer and threw a related code.

I would check the oil and oil filter at this point for metal flakes....as someone just suggested.

[Spanker]

You will see pressure spikes on gauge. But it does sounds as though your VANOS might be clacking. . . based upon where you may have located the sound at the front of bank 2.

If compression was good on all cylinders, then you probably don't have valve to piston contact from a bent valve. Good luck buddy!

Get to wrenching! :-).

Originally Posted by CapeX5

Thanks Spanker, would I actually be seeing "vacuum" in those spots as opposed to pressure? I guess if there is a problem, I would see spikes of pressure as the piston came up and there was no sealing with the valve. Thinking out loud there. Also, I have a mechanic stethoscope that I have used extensively on the engine. The problem is that the aluminum heads/valve covers etc all resonate and throw the noise all over the place. The common denominator is that it seems to be coming from the front of the bank 2 valve cover. There are no abrasion/wear marks anywhere on the valve or timing covers. The only other moving part right there is the VANOS and the chain/sprockets/tensioner for the exhaust cam. Those parts all seem good and I have replaced orings on the tensioner and the rubbing blocks. The tensioner is holding lots of oil and is very difficult to compress when I am dismantling to do the timing work. Again, I am back to the VANOS transmission. Parts arriving today, will be tearing it down again after the misc tests first.

[David.X5]

I had a vision. There are check valves behind the vanos solenoids. I'm betting they are in backwards, preventing the vanos from getting oil and the other tensioner from compressing.

Good news is they can be removed/checked without removing the front cover

[CapeX5]

David-I like the way you are thinking, outside the box. But, I have had them out a couple of times and they are good. Keep the ideas coming. The cam rings arrived today, will be installing tomorrow.

Originally Posted by David.X5

I had a vision. There are check valves behind the vanos solenoids. I'm betting they are in backwards, preventing the vanos from getting oil and the other tensioner from compressing.

Good news is they can be removed/checked without removing the front cover

[CapeX5]

So, I think I may be finally coming to some conclusion with this issue. I took the bank 2 covers off to replace the sealing rings on the cam. While doing that I also needed to replace the oil pan. With that off, I looked up into the motor and saw major scuffing on cylinder #5. You can feel the grooves with a screw driver. Even though I had 140LBs of compression, I am thinking this is the cause of my noise. Piston slap. I found a wiring issue on that coil connection a while ago. The plug was all fouled due to it not firing consistently. I think the cylinder was getting washed with fuel and destroyed it. So, out the engine comes and try to find a decent used one or build another out of 2. I have found a short block and complete X5 motor that had some "timing chain" issues. May just get both of those, evaluate and make one good one. The hours I have put into this thing……..

[X53Jay4.8is]

Originally Posted by CapeX5

So, I think I may be finally coming to some conclusion with this issue. I took the bank 2 covers off to replace the sealing rings on the cam. While doing that I also needed to replace the oil pan. With that off, I looked up into the motor and saw major scuffing on cylinder #5. You can feel the grooves with a screw driver. Even though I had 140LBs of compression, I am thinking this is the cause of my noise. Piston slap. I found a wiring issue on that coil connection a while ago. The plug was all fouled due to it not firing consistently. I think the cylinder was getting washed with fuel and destroyed it. So, out the engine comes and try to find a decent used one or build another out of 2. I have found a short block and complete X5 motor that had some "timing chain" issues. May just get both of those, evaluate and make one good one. The hours I have put into this thing……..

How many miles on the original engine do you have? In any case scored piston walls is a no go. 4.4 engines are plentiful just check the timing guides of the replacement engine and re-seal before putting it back in. Your a pro now.