I read many of the timing failures on here and they all have a common thread. The top timing chain guide failed. Can we replace the top chain guide as a preventative before the chain needs replacement. If I do replace the top guide do I have to lock down the cams with a special tool. My chain was replaced at 65000 miles and now I have 132000. I plan to replace the chain at 150000 again. But I just want to be preventative and since the top guide is so easy to replace.

 

I've only replaced the timing chain stuff once, but I'm in the process of doing it again during a complete rebuild. Changing only the top guide doesn't seem like a good idea, 'specially for a preventative measure. Can it be done without locking cams, etc? --- I haven't tried it, but I'd expect you'd need to at least loosen the tensioner, to allow chain flexibility. As long as the chain doesn't dis-engage from the sprockets, and the sprockets stay tight to the cams, you should be OK. Altho, the new guide will have a different thickness, which will affect the cam timing --- possibly enough to screw it up. And can you get enough chain flex to change the guide without breaking something? --- I doubt it. Maybe someone with more experience can offer some advice ---

If it's in your plans to change the whole chain system in the near future, I'd wait and do it all at once. For "peace-of-mind", maybe move up your target ODO reading. And FYI --- there's a dealer kit available for about $110 that includes all the stuff needed --- chain, 3 guides, front guide bolts, crank sprocket, tensioner. You still need all three sprocket bolts and main seal, but the kit price is a great bargain. Kit # --- 11-31-8-623-601, for my '07 MCS, not sure what else it fits.

Have fun with this project, and best of luck.

 

there should be no issue to replace the top rail. When i was doing my rebuilt, i actually forgot to put that rail in. after starting the car, it sounded strange and it took me a minute to figure it out. then i realized that that piece was not installed. the moral of the story is no need for locking tools or anything, remove and install!

but as mentioned earlier, why not wait to do the whole thing at once while you have the full kit in hand?

 

I autocross and regularly run up to redline under 20 lbs boost. That's why

 

Why you upset brother!

I think the timing chain failure isnt because of that top rail. It is because of the tensioner itself. When it becomes weak, the chain has more slack which will start slapping the rails and stretch even more. With that the whole thing fails, my theory!

 

Before my days with the R56 I drove 944 Porsche. The 2.5 liter Porsche motor with 16 valves has a timing chain driving the two cams. If the upper guide breaks like in our motors it destroys the head. The $25 part saves a very expensive motor. Same concept. I'm still plan to replace everything at 150k but for now $25 will save. The loss of tension or slop created when the top guide breaks starts a chain reaction. In all the posts I've read they say the top guide is missing and it falls into the chain case causing real serious damage.

 

I think the issue which quite possibly may be unique to the Mini engine is the fact that the chain guides disintegrate at more or less the same rate. By this I mean that if your top guide is coming apart, then more than likely the front and rear guides are doing the same. I just did my timing set a few weeks ago and my top guide was fine but both the front and rear were in pieces and yes these pieces were falling down into the oil pan and getting jammed up in the lower timing gear along the way. The system really is poorly designed.

All that to say, go ahead and change the top but get a good light and check out the front and rear while you are in there because more than likely they are at the very least fractured and ready to come apart.

 

Just replace it and make sure you tighten down the bolt. I have seen them chip and disintegrate over time.





https://www.ecstuning.com/Search/SiteSearch/11317546697/





Make sure you inspect the other guides and the chain, check the pan and you want want to drop it to make sure you get all the plastic pieces out.

 

I replaced it today. Hardly any wear after 66000 miles

 

This was the only thread I could find specifically about the top rail guide so forgive the long dead thread revival...

Changed the valve cover in an attempt to fix a vacuum leak and found something odd... I could not put my finger on it and it's cold or side so I carried on, but something relevant to the thread is missing... And evidently has been missing since the dealership did the valve chain guide r+r 20k miles ago...

It runs fine, minus the vacuum leak. But now I'm concerned. How concerned should I be? Does the top guide put any tension on the chain or simply keep the chain straight under high load?


I looked in the chain valley for bits and pieces and I'm 98% sure it didn't eat it.... There's also never been visible particulates, plastic or metal, in the oil or filter. But still

 

It’s like a mechanic broke it off during a timing chain replacement and didn’t notice it when he reinstalled the cam cover. Bad dog.

Peter

 

I DO NOT KNOW if this is the exact correct part you need, for your specific car. 2008 MINI Cooper S Coupe L4 1.6L Engine Timing Guide Rails - 11317546697 - Timing Guide Rail (ecstuning.com)

But you do want that part on there. As you are, the chain is unguided between the two sprockets. I'd guess you can wiggle it up and down a bit. That will lead to premature wear on the chain and sprockets.

 

I was watching a British YouTube on valve guide seal replacement and the mechanic casually mentioned that the top chain guide had broken off inside the engine.

Maybe these top chain guides are more fragile than we thought?

Peter

 

I felt the chain tension while I was in there and it's very tight, maybe a fraction of a mm with over a hundred pounds of force. Granted, the engine is pushing 250hp or better so I guess it's worth putting on a 10 dollar part.. Can it be installed without loosening the timing chain?

 

One other thing I’ve noticed is that there are tow styles of top chain guides. The more robust one (shown in the pictures above) seems to be more likely to fail. How odd. Maybe the flimsy looking one is a later model that allows for more flex without breaking.


R56 Top timing chain guide

 

Be careful, the N14 and N18 use different top chain guides. The on in your picture here is for the N18.

 

 

How long do the chains and guides last? Should they be replaced at 65,000 miles?

Is it just a matter of low oil? Why would higher horsepower in an engine cause more load on a timing chain?

Peter

 

BTW, my mini has the N16 engine.

Peter

 

The answer I'm about to state might've been limited to a specific time period in manufacturing. My understanding was that for a period of time the chain tensioner would provide insufficient pressure/tension on the chain. This allowed the chain to dance/wobble/etc and contribute to guide wear. These combined can lead to improper timing, especially if the chain jumps a tooth on a sprocket. I've also read about stretched chains. Maybe these issues are one in the same, I'm not sure.

Low oil is of course not good, I imagine it could lead to more wear on the guides and possibly the contact points between the chain pins and sprockets. I'd also imagine to a point the VANOS wouldn't like low oil pressure, as that's how they operate.

I don't think more horsepower means more likely timing chain failure. I suppose technically there is more inertial resistance on the chain if the crank is pulling harder on it because of more HP...but if the valve train is happy to rotate freely.... I don't know, I can imagine a measurable difference, but not one that causes chain stretch.
One thing on this that BLOWS MY MIND is that there is not a mechanical link between the crankshaft and the camshafts. Technically there is, the crank hub and the chain, right? BUT, the crank hub is simply PINCHING the lower timing chain gear to the crankshaft. All the engine torque being delivered to the camshafts is relying on torquing the SINGLE crankshaft hub bolt correctly. No splines. No keyway. Nothing. Just pinch resistance. Insanity to my (admittedly simple) mind.

I didn't see WrenchMonkeys question above answered. Might've missed it. Yes, I'd think you can replace that guide without redoing the entire chain/timing. If the car is still in time, no worries.

I'm not at all a reliable source of information, I'm parroting back things I've read here (and sometimes learned). But I also know a lot of things are asked and never answered, so I try. Hopefully someone more knowledgeable will tune in.

EDIT: I know they have an issue with chain stretch as well. I'm not sure if that's related to my first couple of paragraphs above or was an additional/separate manufacturing defect.