Head is off. Dropped valve seat 😕
 

The background: I am new to the forum. I never had a mini before and purchased this car for my daughter’s 16th birthday in December. Unfortunately I got royaly screwed. I did my research and knew these cars had timing chain issues. We went and looked at the car, it was a mess but not one drop of rust. Never driven in the northern NE winters. 117k miles. I take the car for a test ride and plug in my BimmerCode/BimmerLink scanner and no pending codes. CEL not reset in a while. All seems well. I purchase the car for $2800 with brand new tires and brakes. I am thrilled. My wife drives the car home following me for 2.5hrs. I order the timing chain set and valve cover gasket in preparation to fix this before anything bad happens! This is where all the bad starts.

The bad: I am checking the car over to make it perfect. Making my shopping list. Everything from android 13 9” screen with b/u camera to new clams headlights, black grill…the list goes on. But nothing mechanical or major. Yet! I take the valve cover off to replace the gasket and I notice one of the rocker arms not attached, sitting in the bottom of the head. I pop it back on and I can tell something is not right. The valve is not returning high enough. So I figure it’s bent, but why only one? Not the other. My $20 endoscope on my iPhone reveals the valve seat has dropped! Fkkkkk! Now I know exactly what I am in for. The good thing is I was a GM for a few years. Built many engines from 3cyl brp supercharged, 4cyl 11sec drag cars to SBF SBC. But I am bummed that I have to do all this work and now I have more invested than this car will ever be worth.

Where I am at: I have completely compounded the car out with my buffer. Full detail. I have the 2k page Bentley manual I have read top to bottom regarding the timing. Watched YouTube videos as well to make sure I get it right. But here is where I am scared and worried. This cylinder head does not one bit show the age of 117k miles. The combustion chamber cleaned like new to easy. The intake ports are like brand new. So I am wondering what went on here. What caused this one valve to fail? Did someone rebuild or replace this head and do it wrong?

pics
https://cimg4.ibsrv.net/gimg/minicoo...62aecd6a5.jpeg
https://cimg6.ibsrv.net/gimg/minicoo...cfd37be01.jpeg
https://cimg7.ibsrv.net/gimg/minicoo...803bdf2e3.jpeg
This should had concerned me why this last cylinders plug is so bad. This is the #4 with bad valve seat.
https://cimg8.ibsrv.net/gimg/minicoo...83609513c.jpeg
https://cimg9.ibsrv.net/gimg/minicoo...a1cf195ce.jpeg
https://cimg0.ibsrv.net/gimg/minicoo...e82d926c3.jpeg
https://cimg1.ibsrv.net/gimg/minicoo...a7a00f5e6.jpeg
https://cimg3.ibsrv.net/gimg/minicoo...7fdc17755.jpeg
https://cimg5.ibsrv.net/gimg/minicoo...ebf671960.jpeg
https://cimg6.ibsrv.net/gimg/minicoo...318c1aba8.jpeg
Endoscope pic showing valve seat drop
https://cimg7.ibsrv.net/gimg/minicoo...c10bf6154.jpeg
https://cimg8.ibsrv.net/gimg/minicoo...ee4b72e89.jpeg
https://cimg9.ibsrv.net/gimg/minicoo...a3eba548d.jpeg
https://cimg0.ibsrv.net/gimg/minicoo...fba467a4e.jpeg
https://cimg1.ibsrv.net/gimg/minicoo...e6e7c7a59.jpeg
https://cimg4.ibsrv.net/gimg/minicoo...134e1b8db.jpeg
https://cimg5.ibsrv.net/gimg/minicoo...15bf1ce6b.jpeg

I am hoping my local machine shop can replace this valve seat and guide and fit the new valve. I have about $1500 in parts coming from FCP euro and ECS tuning but it all hinges on my machine shop being able to cut the valve seat. I do not want to disassemble the head anymore than it is. I will replace all exhaust valve seals but not the intake. To much work.

Question: Now that it’s apart if I pull the oil pan can I rering and hone it while in the car? Can I easily get to the rods while in the car?