Engine rattle behind timing cover
 

Hi everyone, about two months ago I did a gallery gasket on the 370z and replaced the timing chain and tensioners. Everything has been good since but two days ago the front of the engine started making a rattling noise behind the timing cover at 1k rpm. Not sure what the problem is but iming thinking its related to the brand new chain. I used all oem parts from z1 and followed the fsm to the T with torque specs and all. Any ideas? Not sure if its even safe to drive. There is no rattle after 1k rpm or before it.

https://youtube.com/shorts/tDPt4W8_J...uAUJvzXOA9ztVR

For video couldnt get it to work in the main post.

Don't drive it. The timing chain is rubbing on something. Take it back apart and see what is going on.

Did you forget to let one of the tensioners out? In otherwords, take the hairpin out that holds them in compressed condition?

No I triple checked everything was right and pulled the pin on the tensioner. Everything worked fine for over two months. The problem just started a day or so ago.

I assume new chain guides as well? New tensioners? Something may have come loose on you. It happens.

Hard to say, but it sounds like chain slop.

Ultimately, I think you are taking it apart. No point guessing.

Yea all new chain guides as well. My guess is the new tensioner is bad because the noise goes away after 1k rpm when its building more oil pressure in turn pushing the tensioner out on the guide. But you are right it has to come apart again. Think im taking it to a shop this time because i dont have the time to do it sadly.

Ah hate to see this! If oil pressure is a suspect, it would be interesting to see what it's reading at 1k rpm when the rattle is present.

Turned out to be an idler pulley bearing. That would explain why there was no codes and the engine performance was fine.

You didn't check them when you did the galley gaskets? They would have been making noises then. At least it was something simple.

I actually replaced all three when i was putting the front cover back on. My mistake was i didnt use OEm for the pulleys which i knew would bite me in the ***, and it did. Thats autozone quality for ya. Thankfully i went OEM with everything else it was just i needed them in a pinch and figured they wouldnt fail in two months…

Ouch, Oh yeah that will get ya.

Found out the same thing with my Murano. Except it was a name brand aftermarket kit, Dayco. First the belt ripped after 2 weeks and it took out one of the Idlers. Or other way around. bearing spins but squeeks

Dayco was the brand i got too ironically…. It looked good because it seemed like it was machined well. But i guess the bearing is bad in those. Not sure what the supplier for bearings they use is but ill avoid them going forward.

Ya, I used to alawys buy Gates over Dayco. Unfortunatley, at the time, Rock auto only sold Dayco for my vehicle.

Ironically, today, RA is once again selling Gates for my Murano and the dayco kit is removed.

So I'm wondering if there has been many returns to RA and there might be a Dayco manufacturing issue?