Possible placement of the N14B16A head on the N18B16A block.

[developer]

Cylinder 2 of my N14B16A is not experiencing any compression.
Carbon is present on valves. The pistons have a deep black coloration.

The cylinder head has not yet been removed.
The odometer indicates a number of 300,000 miles, although it is uncertain if the engine is original. The cam chain tensioner is an improved variant. Therefore, I believe that the engine was upheld, at least initially. Since the engine has accumulated a minimum of 150,000 km, it is in need of a new lease.
Locating second-hand N14 engines with low mileage is quite difficult.
A low mileage N18B16A with ancillaries was determined to be more cost-effective compared to a short block.
I have heard that compatibility is limited to the changing of the ECU and CAS from the N18. However, I am curious whether it is possible to replace the N14 head and oil pump with the N18 in order to get an almost new engine.
From my observation, the pistons, intake valves, and camshafts differ between the N14 and N18 models. There is no difference between the exhaust valves, crankshaft, and head gasket.
Can the valves not make contact with the pistons?
We appreciate any suggestions.

[DSM10000]

If there is no compression on a single cylinder, it may indicate either a malfunctioning valve or a damaged piston. The damage to the piston cannot be seen until the head is removed. I will provide a photograph of engines without compression.

Regardless, the head must be removed and there is no room for speculation. What is the rationale for substituting a used head from a different vehicle when the damaged valve can be easily replaced or the head can be refreshed? If it is a piston, then a bottom end refresh would be necessary. Personally, I believe it would be less troublesome.
The appearance of your piston is a result of its saturation with gasoline caused by the absence of compression.

[DSM10000]

[developer]

Thank you for your feedback.
I am unwilling to have a head replacement. I want to restore and upgrade it, and then mount it on a N18 cylinder block with a mileage of just 40,000 km.
I am inquiring about the feasibility of achieving interference-free operation between pistons and valves.

[ianwh4]

I have not previously attempted to utilise the bottom end of a N18 on a N14. However, there are a few notable differences. For instance, the N18 is equipped with a UCE guided oil pump. If the bores on the N14 are not damaged, just replace the piston, hone it, and proceed with the same process.
I have successfully converted many N12 engines to N16 engines, with some minor adjustments required. However, I have not yet performed a turbo engine switch, as you have said. It may be feasible to do such a swap. If you decide to do so, please share your results on this platform to assist others. Based on my intuition, it is conceivable.
The n14 oil pump should be used, whereas the n14 crankshaft timing ring should be employed at the end of the crank.
The n14 intake and exhaust sensors are used in conjunction with the throttle body.
4. The crucial factor is the disparity in the head chambers where the valves are located. If the differences align, then it would be deemed acceptable to proceed.
Personally, if I were going to the N18 in a N14 vehicle, I would replace the whole engine, harness, and ECU. Additionally, I would carefully connect the four wires to establish communication between the ECU and the N14 car. However, the person who questioned me about this matter was not trustworthy. Below is a link that is worth examining.

https://www.northamericanmotoring.com/forums/r55-clubman-talk-2008/317021-08-clubman-s-with-12-n18-engine-swap.html

[developer]

We appreciate your assistance. Undoubtedly, if I were in the United Kingdom, I would offer you the job. I really valued all of your messages and guidance.
If I had the N18 harness and ECU, I would undoubtedly use the whole B18 engine. Another consideration is that my gearbox is automatic, so I need the appropriate Electronic Control Unit (ECU), correct?Uncertain

[Mistral]

ianwh4 surpassed me in mentioning the variable oil pump and the solenoid, which are regulated by the dme. Therefore, it is evident that there are certain aspects to address regarding wiring and ecu (including the cas unit for keys, among others).

If the piston is a piston, I have polished the cylinder and inserted a Yenmak piston (77.000mm) to achieve the desired piston clearance within the specified range.

[ianwh4]

i just completely another n12 2008 cooper i fitted a complete n16b16 engine from a 2015 mini cooper , the oil pump fairly easy thing so sort there is a few other things that need to be worked out , i've also honed a damage bore foe times and have welded the the melted part 3 of these cars out there now and still running ok so its possible to repair the bore, as very last resort, i also fit over size rings on a near end of hone bores before, then trim the ring gap to suit, as the rings I use have a good bit of tensile spring to them , and will work on a standard piston , last one i done hone was out to 1mm had to get a tad inventive with ring gaps and rings as you do, this all said i would always rather have a know good block and can trust it when crack it open from the lights lol