I purchased this 2010 JCW six months ago - knowing it had some type of engine problem. Beautiful car - low miles, spotless interior, not so much as a door ding. N14 engine with mods.

When I received the car, truth be told I did not know if was a JCW - by the VIN number, it was an S model. Upon closer inspection, however, it has every dealer JCW upgrade applied - engine (injectors, cat+exhaust, DME JCW tune), suspension - cross bar, sway bar, brake kit front & back, gauge kit.

In any event, the car started - but ran very rough. Threw a misfire cylinder #2 code. Checked compression: 125 -25 - 150 - 145. Figured cracked valve - since the tensioner was fine and timing was spot on.

So begins the tear down, and I will spare you the boring details of pulling the engine apart, just a few pictures! I decided to pull the head, assuming either cracked valve or bent valve, since putting a boroscope in cylinder #2 / #1 showed nothing but a clean piston.


Service Position with the valve cover removed

Closeup of the top of the cylinder head. PO definitely used synth oil and changed it regularly!



Block after cylinder head removed:


First look at the bottom of the head, ew



And a closeup of the valves in cylinder 2:


Despite the crud on both sides of the valve, no cracks - but I noticed the valve didnt seat fully...




So - fired up the sand blaster, actually walnut shell blaster, and started cleaning. Now the head looks like:






Now all 4 cylinders are holding pressure - just for a serious cleaning.
Since this head was so bad - not sure walnut blasting through the intake manifold alone would do it - too far gone.
I am adding a catch can, and doing a few more upgrades while the head is off.
I will update with final compression numbers after the head is back on.

 

Moral of this story-
Clean your intake valves!! Install a catch can!!

 

nice...looks good...share pix of the JCW