Well I dived into a quick bit of auto maintenance this afternoon. I was having an occasional cold start rattle that the dealer could not duplicate. Now that I am out of warranty I went ahead and changed the cam chain tensioner and the problem has not returned. (New part number used) While I was in the area I pulled the noisemaker and inspected the intake valves for carbon build up. I was pleasantly surprised that the valves did not look that bad. Compared to other pictures I have seen, I'm doing pretty good at 50K miles. Don't get me started on that ridiculous noise maker, what a waste of engineering that thing is!

 

John, great that you dove in and addressed your tensioner issue. I've changed one also and it really isn't that difficult of a job. The hardest thing I came across was removing all the intake hoses that were "welded" in place due to the heat to make access to the tensioner easier. There is so much talk about these tensioner issues, it's great to see folks dig in, fix it and write about how easy it was.....well done.

 

Thanks Kukaepe!

My real test for the rattle will be tomorrow morning, temps are expected to get below freezing here in Denver tonight.

Cross yer fingers

 

I think a cautionary word is needed in this thread, first just take a step back, and think why your experiencing the rattle in the first place ?

The reason you have a rattle is that the chain has stretched, beyond the original tensioners working length, so the engineers revised the original tensioner, and gave it an extra 10mm in the length of the piston, now although that seems like a good idea!! Just have a little think about that.

What you should be understanding is, that although the new revised tensioner when fitted, will for a while stop the rattle, this is not a final solution to the rattle, you have simply applied a greater working travel length piston of 10mm to take up stretched slack, in an already stretched timing chain, and so now your in a situation, where you are applying a greater applied force to an already stretched chain, which can and has in quite a few cases, stretched the timing chain, way beyond it's original working stretch limits, to such an extent, that the timing chain has failed, resulting in total catastrophic engine failure.

So just a word of warning, please don't think that a simple tensioner change, is going to cure your rattle, unless you know the amount of stretch in your timing chain, the fitting of the tensioner may (for some) be a foolish short lived remedy!

 

I bought an 09 MCS two weeks ago, from the dealer, it just hit 20,000km and had a slight raddal in the cool mornings, I took it in and and they could not reproduce, we didn't need the car for a few days so they kept trying it in the mornings. Low and behold the forth day they heard it. And in went a new tensioner. Unlike others I know that this is very likely a long term fix, if not i'll put the new chain in 2 years from now.

 

Czar, I agree with you......... mostly. If the issue truly is a stretched chain, then yes, you have just delayed the inevitable and also modified your cam timing because the longer chain will alter the gear phasing angles. However, if the real issue here is the underengineered POS tensioner piston that prob has more engineering changes than a simple 10mm length variation (revised tensioning system to maintain clearances), this should be a recall service to get it right. Obviously BMW has strenuously resisted this and that makes me quite angry. $4995 Yugos used to blow their engines at 35K, a $33K BMW shouldnt. Apparently at about 38K my engine had a new turbo and some internal cam related work done, so I'm assuming the tensioner was corrected. It pisses me off to no end that I buy a car and do not have a Federal right to see what parts were replaced by the original owner(s). That needs to change.

 

My understanding of the R56 timing chain issues with the earlier cars ('07 - '08) was one of quality control on the length of the timing chain. This may explain why not all cars with the N14 engine have the "death rattle" issue. I don't know the percentage of N14 cars that are affected but I'm guessing it isn't statistically significant or MINI would provide extended coverage on the problem as they have done on the high pressure fuel pump. If the chain was under engineered, resulting in stretch, then I would expect much higher percentage of affected cars. In addition, if the chain was under engineered I would also expect higher numbers of cars affected when the condition based oil change intervals (OCI) or longer than condition based intervals were used. I have not read about a relationship between OCI or mileage relative to the timing chain and tensioner issues. As someone who doesn't believe in the condition based service, I changed the oil in my N14 at 2K, 5K and every 5K from then after. I believe that my "long" chain was due to poor quality control of the part and not stretch. Where this argument falls apart is if the problem was one of quality control of the length of the timing chain, one would expect that MINI would have resolved the issue by now. If the problem is one of a "slightly long" original chain or by wear due to long OCI, then a tensioner with more "throw" to accommodate the "slight" additional length seems like a reasonable solution. The MINI repair procedure I have seen requires the chain length to be measured (indirectly via the tensioner opening in the cylinder head). If the measurement exceeds a certain amount then the chain, guides and other parts must all be replaced. This verifies that beyond a certain length of chain that the tensioner with additional "throw" is not an acceptable solution. I hope this makes some sense and sheds some additional light on the issue.

 

You may be correct.

I have a feeling that Mini might have had a small defect that had large effects.

Rotating chains at very high RPM'S has a tendency to "kick out" and bow. Any one that has used a chain operated hoist would be familure with this effect. If you pull as hard and fast on the chain as you can, the section of chain returning to the hoist wants to kick out and walk in a new shape, in stead of going straight up. It's centrifical force in action, the chain is trying to stay in motion but is changing direction rapitaly.

In an engine they don't run the chain super taught. Instead they run it loose-ish to keep from having a side loading force on the cams. So they incorporate a slide tensioner that the chain slides against, this tensioner pushes the chrain to remove slack and to keep it from bowing outwards at high speed.

This slide works on a fulcrum, with a tension spring at one end, think a wheel-borrow. When the chain is spinning at high speed it's forcing the tensioner into compression. And as the speed decreases the tensioner pushes back. But even at a constant speed the chain wants to osolate back and forth, wearing out the spring.

If the old tensioner was to week or to short or both. You would see the chain moving with relative freedom and slapping until it stretched. Now after all that wear Mini needed to replace everything.

What I feel is happening is that they find if the chain hasn't stretched to much its not to late. And if it has then they replace everything. But that the tensioner really is the problem.

Either way a high engine speed that chain is pushing back on a tensioner with huge amounts of force, that isn't constant. If that spring to begin with was weak or was short so that the spring wasn't at its full optimum force at any givin time. That timing chain was slapping it self like mad until it stretched.

My two cents