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The Mini R56 N14 JCW is experiencing excessive oil consumption.


Grundysp

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Greetings to all members of our community.
I am seeking assistance for the problem I am now experiencing.
Previously, I had issues with burning oil while accelerating from (A) traffic signals and (B) after descending a slope and then accelerating again. This occurrence was more frequent after the automobile had been in operation for an extended period of time. I have just had my automobile examined by a local mechanic, and they determined that the issue lies with the valve stem oil seals, which have become worn.
After procrastinating for a year owing to the expense and complexity of the task, I finally replaced the valve seals and valves, as well as installed a reconditioned head. All other seals were modified correspondingly to ensure certainty. I am experiencing a little emission of oil while accelerating from traffic lights, but not at the first startup.
The turbo was replaced 500 miles ago with a brand new turbo. I have installed a catch can on the CCV (Crankcase Ventilation) system, but I have not installed one on the PCV (Positive Crankcase Ventilation) system. The automobile operates flawlessly, devoid of any malfunctions or error codes, and accelerates as expected, with the exception of the smoke, of course.
I conducted a compression test (without any lubrication) and obtained pressure readings of 140, 135, 140, and 135 pounds per square inch (PSI) throughout the cylinders. The automobile has accumulated a mileage of 142,000 kilometres and has received diligent maintenance and care from its previous owners.
I will clean the intercooler to remove any remaining oil. Uncertain about any other details I could have overlooked? I am seeking guidance to resolve this problem. Some individuals have suggested that I only need to operate the vehicle in order to eliminate any remaining oil in the exhaust or turbo before replacing the cylinder head. Apologies for the lengthy explanation, but I believe that providing more detail would enhance the quality of the content. I appreciate any assistance and guidance you can provide me with in advance. Sincerely.

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I would like to note that the rocker cover was recently changed with an authentic small cover in order to exclude the possibility of a faulty PCV in the cover. However, this replacement did not provide any improvement.

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In addition, the smoke emitted from the vehicle appears blue while accelerating from a stationary position, but returns to normal during regular drive.

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It is quite probable that the issue lies with the valve stem oil seals and the low-quality plastic rings utilised by BMW on the pistons. Upon visual examination, it seems that the chain is stretched, however it may be hard to ascertain with certainty. Inspect the pipes and turbo for any potential leaks while examining the turbo setup.

I recommend doing a comprehensive update by examining his writings as a reference. If the vehicle is also using coolant, it is advisable to replace the water pump with a Pierburg brand, the rear link pipe with a BMW brand, and the thermo housing with a Febi brand.

When replacing any item, it is advisable to exclusively utilise authentic, commercially available parts. Generic, internet-sourced components are of inferior quality.

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It seems that the engine requires an overhaul, including the replacement of the piston rings and stem seals. Additionally, it would be beneficial to consider replacing the turbo's CHRA (centre housing rotating assembly) while the engine is being worked on.

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I appreciate the responses.
I would like to inform you that the valve stem oil seals were recently replaced with authentic micro seals, along with the installation of new valves, less than a week ago. The chain has accumulated less than 500 miles since it was last replaced one year ago. Fortunately, I replaced all of the turbo oil feeds when I installed the new turbo less than a year ago. Essentially, all the necessary replacements have been made, with the exception of the piston rings. Fortunately, it is not using any coolant.

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The N14 Cooper S engine is known for a recurring problem of piston breakage on skirts number 3 or 4. This issue is typically accompanied by heavy smoke, a slight or significant misfire, and excessive blowby. When customers approach me for repairs, many of them request a quote for stem seal replacement, as they have been informed by their previous mechanics that this is the root cause. However, I decline to solely address the stem seals because, in most cases, the problem is a combination of faulty rings and stem seals. Therefore, it is more efficient to address all the potential issues while the engine is being worked on, including replacing the head bolts and head gasket. This approach ensures that the problem is fully resolved, preventing any further smoking issues. Consequently, my current recommendation is to refresh the engine and address all the potential issues at once to ensure a successful repair.

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In addition, it should be noted that the use of a decat or sports cat may lead to a low fuel mixture, resulting in excessive heat in the rings and valves. This can cause the stem seals to melt and the factory rings to lose their tensile strength over time.

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The vehicle was equipped with a Miltek sports catalytic converter when I bought it. I will shortly do a wet compression test to get accurate data.
The head has undergone a full replacement and all seals have been replaced.

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