The timing chain in my 06 MCSC (with ~34k on it) broke. The car is currently at the dealer. When I spoke with the service manager today he mentioned a few things which I am now questioning.
He said the engine is non-interference (when I asked what else was damaged) and that they had done a leak down test and all the cylinders looked OK, but that there were some pieces of the chain in the oil pan. I used to be a SA at Saturn and when people brought their cars in with broken timing chains, they typically needed a new engine. My fiance and I looked on MINI2 and the 3 mentions of timing chain breakage all said their engines were replaced.
From what the manager said, there wasn't any additional damage (which I now find kind of hard to believe) and that they are just replacing the timing chain. What's the likelihood that nothing else was damaged? We're looking at the service manual now and it doesn't seem possible that pieces of the chain and metal shavings couldn't get into other areas of the engine and cause damage. (In addition to the pistons crashing into the valves when the breakage occurred).
If anyone else has been through this (long shot I know) and/or has some insight I would appreciate it. They are replacing the chain on Monday, and I assume if there is further damage to the engine it would become apparent when they try to start the car. I just want to be armed with as much info as possible and ask the right questions when I speak to them on Monday.

 

I believe that the engine in your & my MINI are non-interference. The new R56 MINI with the French engine is an interference engine. Perhaps that is what you were reading about on MINI2. I have read of a few R56 MINI's breaking their chains & requiring new engines.

If you had an interference engine it would be a goner. The chances are slight that the chain breaking would cause any additional damage in your MINI's noninterference engine. It's going to be OK.....

 

a non-interference engine is one where the valves won't hit the pistons when the crank is rotated and the valves are open. An interference engine will hit the valves, doing in the valves, the pistons and probably the valve guides (if not more of the valve train).

There is a screen the will prevent larger pieces from being picked up by the oil pump, and after the oil pump itself, the oil goes through the filter.

Matt

 

Thanks for the info about the screen. The fiance explained to me the difference between non-interference and interference engine. While the manager said the car was non-interference several people I have talk to were surprised by this and though the car was interference, hence my concerns.

 

The question that still needs to be answered is why did the chain break? My guess would be that something in the valve train is binding. You may have other problems, and the next time the chain breaks be out of warranty.

 

Yes, this is also a question. The car had been whining excessively for a few weeks before this, so we're wondering if something was binding and making the noise. The manager seemed concerned about finding out why this happened as well, as he said he had never seen it happen in a MINI Tritec engine, so he said they were going to be looking around for this as well.

 

These are definitely interference engines....Ask me how I know! Ok, then. I have literally installed a hundred of these cylinder heads for various reasons and one day I was in a rush to get one done. I always mark the relationship in between the cam gear and the chain(the only other way to do it is to spin the engine over dozens of times to get the marks on the chain to line up with the sprocket). Regardless, marking it works fine unless rushing like I did, wound up getting it a couple of teeth off and when i turned the key and tried to start it, something was definitely not sounding right. I quickly realized what I had done and removed the head to find all of the valves bent(can't remember whether it was intake or exhaust) and the shrouds that go around the valve guide as well as the guide itself were broken. No damage to the pistons, but this for sure rules this engine out as a non-interference engine.

I believe that this was a Non-S, but the valve train is the same. The pistons are dished to have lower compression suitable for a SC'd motor, but that doesn't gurantee that it's an interference free engine.

They will find out when they try and start it up, that's for sure.

 

I would double, triple check what the SA saying is true. Call up other dealers or independent garages. The chance of an interference engine surviving a timing chain/belt failure is slim. Make sure they perform a *leak-down test* and not a compression test. And I would want to be there and see the numbers.

 

I was told that they did perform a leak down test already and everything checked out fine.
I'm getting mixed answers as to whether or not the MINI engine is interference or not. If it is non-interference like the manager said then I worry a bit less about other components of the engine being damaged.
Regardless, I would think that it would be apparent if the chain caused other damage to the engine when they try to start the car and that this would be address. This work is being done under warranty so if the car isn't running right I will certainly bring it back.

 

 

Hi Meg, I know this is REALLY late. (2 years) But As I was driving down the Road on the Freeway my Mini just died down, and stopped.
She's in the shop as we speak and I keep getting the same thing you did. -- Mixed answers on non-interference and well , you know....... hehe
I just wanna know what did happen to your MINI? was it pooched? or was she ok?
I cant take it anymore, the uncertainty is killing me!!!
thanks in advance

 

I think it is possible that the R50 is an interference engine but the R53 is not (due to the lower compression). Am I wrong?