Hi, I am rebuilding my M119.960 engine 220,000kms and would appreciate your thoughts on the chrome piston rings and Alusil cylinder bore finish.
The engine was really good and powerful except for a loud knocking noise which turned out to be caused by a broken plastic top left timing chain guide rail and the resulting timing chain banging of the timing chain cover OR one conrod bearing is also past its best.
I am going to replace the main crankshaft and conrod bearings but I think I am just going to just keep the original piston rings and not touch the cylinder bores other than a good clean with soapy water and petrol. I will just clean the rings as best I can without removing them unless anyone suggests otherwise as I'm scared of bending or breaking them.
There seems to be some people who say change the rings and hone the bores but others who say don't touch them. I'm leaning towards don't touch them especially as new rings are about 150 euros a piston. I think maybe the delicate Alusil bores need to be treated with extreme care and at most honed with felt pads and a special paste which I'm nervous about trusting anyone to do in southern Spain. I also think the chrome rings are probably harder than the Alusil cylinder bores so in this case its the bores that have to bed in and not the rings. Maybe brand new hard piston rings might do more harm than good to a used block so I think I'm staying with the old ones.
I would appreciate you thoughts on this.
The engine was really good and powerful except for a loud knocking noise which turned out to be caused by a broken plastic top left timing chain guide rail and the resulting timing chain banging of the timing chain cover OR one conrod bearing is also past its best.
I am going to replace the main crankshaft and conrod bearings but I think I am just going to just keep the original piston rings and not touch the cylinder bores other than a good clean with soapy water and petrol. I will just clean the rings as best I can without removing them unless anyone suggests otherwise as I'm scared of bending or breaking them.
There seems to be some people who say change the rings and hone the bores but others who say don't touch them. I'm leaning towards don't touch them especially as new rings are about 150 euros a piston. I think maybe the delicate Alusil bores need to be treated with extreme care and at most honed with felt pads and a special paste which I'm nervous about trusting anyone to do in southern Spain. I also think the chrome rings are probably harder than the Alusil cylinder bores so in this case its the bores that have to bed in and not the rings. Maybe brand new hard piston rings might do more harm than good to a used block so I think I'm staying with the old ones.
I would appreciate you thoughts on this.
Last edited:
