Hi guys and gals,

I have an R56 Cooper S. I find that idle is slightly lumpy when the engine is cold. That is not to say the revs fluctuate or anything, it's just the vibration feeling of the engine I'm talking about.

I recently used Torque Pro to read the misfire data from the ECU. It shows that when the engine is cold, I get an average of 2-3 misfires always on cylinder 1. I can certainly feel when that happens, but the slight lumpy vibrations are there all the time at idle until the engine is warm even though not as serious as a misfire.

I'm guessing that although I don't get a misfire, the cylinder must not be combusting properly when cold and that gives the slightly juddery idle vibrations.

I already have changed the coil sticks around and the misfire stays with cylinder 1. New spark plugs coming but I don't think the current ones look too bad.

I tried to clean my intake valves the other week. While I did get a lot of crap off them, I didn't do a perfect job - that gunk is just so sticky and thick!

I was wondering how easy it is to clean the exhaust valves? What do I need to do to get at them?

Is there some way to confirm if the issue is an issue with exhaust valves or the head gasket? Both would give lower compression readings right? Annoyingly my compression tester doesn't have a 12mm fitting so I might need to beg / borrow a different one. Would either exhaust / head gasket be more likely to improve with warm-up?

 

Exhaust valves and ports are pretty easy to clean. The hardest thing is removing the exhaust manifold and associated parts. I just cleaned mine. Lift the car up, remove shields, catalytic converter and sensors, hoses and inlet for turbo, and remove turbo and manifold as a unit. I also redid my intakes. She does run smoother.

 

Do you have some pictures? And / Or could you give a more detailed run-down of how to remove the exhaust manifold and turbo as a unit, please? I've never touched the exhaust side before.

 

You should buy a Bentley's manual for general outline. I did manage to take the turbo off separately, but there is no point in doing so. The turbo fasteners have to be torqued if removed. Not easy to do separately. It's easier just to attach back in as a unit. You'll need to drain coolant and oil. I would replace the turbo oil supply line and also replace the gasket for the oil filter adapter.


Manifold and turbo removed.

 

Thanks for the details!

I'm a bit tight for money right now so dont want to buy a bentley manual. Any more details you can offer on the proceedure would be greatly appreciated

How long did it take you?

 

Just a quick thought which might be stupid - how possible do you think it might be just to crack the exhaust manifold off enough to get a small tube in and soak the valves to help loosen up the crud? Can the bolts be accesed without removing lots of other stuff?

I wonder if that might be enough to restore compression on my cylinder without a full removal.

 

You don't want to do that. Not sure if the gasket is single use or not. I replaced mine it's improved and has more shielding than my original. The main reason is you'll want to close the valves and clean one port at a time. If you're doing both exhaust and intake you'll be able to clean two ports at a time. You don't want the crud going into your cylinder. You close the valve by turning the crank shaft in the clockwise direction. I'd remove the spark plugs. In the end you can try to vacuum out any debris that might fall into the cylinder. I used carb cleaner, toothbrushes, picks, and other misc tools to pry the hard deposits off. Helps to have a compressor to blow out the crud from the port keeping a paper towel around the nozzle so it won't go all over your engine bay.

 

It's a good weekend job, but it really is a good idea to have a manual.

 

There's a write up here on doing a manual clean of the intake side. The process will be similar.

 

Do you have pics of the exhaust valves?
They shouldn't suffer the same fate as the intake valves. Not sure why you need to clean them. The intake valves - another story.

 

Get your compression checked. Bore
Scope the cylinder. Just did this for a friend and he's lost compression by 50 percent on two holes. If yours tests low on that cylinder and the bore scope shows a wet cylinder, you have further diagnosis to do. These engines can crack pistons when knocking. First sign is rough running and misfire that won't move when coil is swapped.

 

Dots anyone know if injectors can be swapped from one cylinder to another on the same car to check if the issue follows a particular injector? If theybare not the issue can they be kept in that order or will they need re-coding or returning to their original locations?

 

Eventually everything fouls up.

 

Cleaning exhaust. The ports and valves were full of hard crusted residue. It's nine years use. They are not going to remain clean. The pictures actually look cleaner than it was. Spraying carb cleaner and brushing and you get a bunch of crud out. There's enough there to interfere with the function of the valves. I cleaned the valves as much as I could. While I don't think the exhaust needs cleaning as often as the intakes, they do need cleaning.


Almost clean...

 

Thank you for sharing!

 

Don't even think about swapping injectors! Yes, it can be done, but you need a special tool for the seals when playing with FI.

 

What kind of special tool? Something I can get on eBay?

 

Should always include model year as there are engine differences 2011 and up. Mileage too.....many wearable parts have a typical life expectancy aiding in diagnosis.

If an earlier R56-S with N14 engine, could be carbon buildup on valves requiring walnut blasting.

 

The BMW (Mini) part number is 83 30 0 495 756. This is for the '07MCS. I don't know what other model years it fits. Mine came from a dealer, but they might be available elsewhere. Check with some of the NAM vendors. I wouldn't try switching injectors without replacing the seals first. And even then, I haven't heard / read about anyone having a failed injector --- too many other causes for your problem.

 

Any signs of oil leaks?