I think the guide failed then the tensioner.

 

Got I back together today and started her up. Very quite compared to what it was before. Took it for a spin and seems fine. Will have to see if leaks or other items crop up.

When I pulled a rod cap the bearing had some small pits. No experance to say if the wear was normal. Did not have any scores or unusual wear. Was interesting that the rods are the type that are broke apart rather than machined. I have read they are stronger.

Oil pan went back on better than anticipated. I did not remove the pickup, but did get a few more pieces out of it with compressed air and raps of a hammer.

No real issues putting back together. I thought it was easier to put back together than take apart. Had to make a tool to hold balance while I torqued it.

Might have been over kill to by an oil pump but better safe than sorry.

I'll post a few more photos later.

 

Why do you say guide then tensioner? Which guide? Right black color where the bolts failed or right movable one against the tesioner?

My guess was tensioner failed allowed chain slap and caused stress on the right black station guide and bolts.

I suppose the right black guide bolts could have failed or come out and caused excessive slap.

 

Did you replace the rod bolts when you split the rod cap? if not I hate to be the bearer of bad news here, but they are torque to yield and need to be replaced like the head bolts and mains.

 

The (new) tensioner fails IF there is too much play in the chain, it over-extends. The guides wear because they are plastic/nylon whatever, the last ones I saw were worn almost through.

From the looks of your pictures the tensioner came into direct contact with the chain and was ripped apart. It normally is in contact with the guide.

I saw a Cobalt that tore even the oil nozzle apart when the chain failed.

 

It is usally the stationary guide that fails, causing a sloppy chain then broken tensioner.

 

I concur with the idea the stationary guide fails then the tensioner fails. If this is the case replacing the tensioner would not have prevented the failure. Maybe the ARP bolts I used to fasten the tensioners will help? I thought about the replacing the rod bolts since they were torque to yield but was to lazy to check. I hope I do not regret this action. Again this is why I am not a pro mechanic but a wanna be.


ARP high strength timing chain guide bolts and bushings.


Stock timing chain guide bolts


Rod bearings


Torque harmonic balancer bolt


Bottom of engine with oil pan removed.

 

Do you have the ARP part numbers? Those numbers would be good to have for people looking replace the std bolts with high strength bolts.

 

You should be able to paste several pix into one post. Did you try and have a problem?

 

I fixed the pictures, now about those ARP guide bolt numbers are these them?


ARP Ecotec Timing Chain Guide Bolt Set 11588522R