Timing guide wear. What would cause this?

[Dsteinhorst]

My motor has had a noise recently at certain RPM and engine temperatures. It has gotten more frequent and repeatable lately, so I pulled the valve cover and found wear on the top timing chain guide from the chain pins.

This is a stcok internal 2.2 LAP supercharged with about 5k miles on a fresh timing chain job (Completed Feb 2021.) Have had no noises or other issues until recently. Car still drove just fine.

If anyone has insight on what may cause this, I would greatly appreciate it. I'm going to throw in a new tensioner and guide to get going again.

 

[jirwin]

Hmmm you did the balance shaft delete right? I wonder if the extra vibrations contribute. Doesn't really make sense though as you think you'd hear that right away

 

[Desert Sasqwatch]

What does the timings chain look like since it was rubbing on the metal bracket? The chain alignment was not correct as it should have been only in contact with the plastic guide. Assuming you inspected everything else and the rest of the guides are okay?

 

[ah.b.normal]

My motor has had a noise recently at certain RPM and engine temperatures. It has gotten more frequent and repeatable lately, so I pulled the valve cover and found wear on the top timing chain guide from the chain pins.

View attachment 41243

This is a stcok internal 2.2 LAP supercharged with about 5k miles on a fresh timing chain job (Completed Feb 2021.) Have had no noises or other issues until recently. Car still drove just fine.

If anyone has insight on what may cause this, I would greatly appreciate it. I'm going to throw in a new tensioner and guide to get going again.

Is the cam gear on the exhaust cam all the way on or loose? The key on the cam would keep it timed but the gear could walk. And if the bolt is long enough it would rub the valve cover and not walk all the way out.

 

[Dsteinhorst]

I did do the old school balance shaft delete with the drive in plugs and idlers. That all seems fine. There was a noticeable increase in vibration, but nothing that would cause significant problems. (I will leave them in when I do my LE5 build in the future though)

The timing chain looks completely normal. No visual difference between the side that rubbed and the side that didn't. I imagine the chain is much harder than the guide.

I pulled the lower case cover off yesterday and everything looks great. Nothing loose and no other wear. Cam bolts are torqued and no play.

At this point, I'm thinking it was an improperly made guide or a tensioner that died way early. Both are fairly unlikely. Theres not enough adjustment for me to have put it in wrong; only a few thousandths movement. Going to throw it together when I get the new tensioner Wednesday and let it rip.