R55 Valve Job and New Piston Rings- Notebook

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Sep 15, 2024 | 03:19 PM

GoFastJimmy

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Joined: Nov 2023

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From: Memphis, TN

Valve Job and New Piston Rings- Notebook

So I just finished a 9 month task of repairing my R55 after burning a valve at 147,000 miles. Car is back on the road for several weeks, got about 1,000 miles done, runs perfectly. Got the car at 140,000 and had no idea of the maintenance history. At about 142,000 I replaced the timing gear, turbo oil supply and return, oil filter gaskets, vac pump gaskets, and valve cover gasket. It used oil, about a quart every 1,000 miles and I knew valve seals were probably why. Dropped the valve on Cyl 2 during a long trip, nursed it home, got up the courage to pull the head. I have done lots of car things, the most complex being timing belt changes, but I knew from this forum that I could do it. Here are my learnings:

Get used to being uncomfortable- This job was beyond my current skill level, but I read and watched all I could about how others did it, and when I came to questions I could not answer (Stone-hone or ball-hone better? Hone with the crank in and try to catch and clean debris or go ahead and remove the crank? Self-clean the injectors the best I can or send to a professional? Do I need new injectors? Are these piston bearings good?) I had to balance cost with risk and my doubts, many of these services are expensive and I really did not know the right answers. I was very uncomfortable at times but I just kept moving forward. I had never honed a cylinder before and I really doubted if I could do it, but it was not that hard in the end. Same with removing the pistons, installing rings (the order and orientation is so critical, I had to be very careful), and removing/reinstalling the oil pump. Hard at first but then it’s done and you did it!
Get ready to read/hear about how bad your Mini is- Mini hate is everywhere, especially on Youtube. Ignore it. Those resources are needed to see methods I just could not understand just by reading. Loads of opinions out there, and everything will break if not maintained, but when you put the wrenches to something you get to see for yourself what is what, and I think my Mini is great, well made, engineered in a logical way, and fun to work on and drive. Ignore the haters.
Be patient- My 1st assembly was undone by my having plugged the injectors in wrong, so the car would not start even though it was cranking. I panicked and disassembled to pull the head again, a mistake. New head gasket, new stretch bolts, lots of time later I reassembled again and I am convinced it was fine the first time, but I did learn. The one job that took the longest was reinstalling the downpipe exhaust ring, it just did not want to go back on, until it did and I have no idea what I did differently that 51st time.
Be resourceful- My town (Memphis) does not have a lot of Cylinder Head Service shops, most are race-related here, and a couple more said they don’t touch Mini heads. I needed to look outside of Memphis. Atlanta is about 6 hours drive and has several that work on Mini heads and quoted me just under $1,000 plus shipping for a full service and maybe more depending on what they find. Considering I really don’t know what I am doing and wanting to spend less I kept looking and found a guy near where my family lives in Oklahoma (also a 6 hour drive) with a shop, been in business for a long time doing heads and just happened to have done a Mini head recently, charged me $425 and I brought it to him and picked it up. I already had the valve seal set, and he only had to replace the one valve, and all the guides. All else checked out good.
Be prepared for all the tools- Compression gauges, leak down tester, timing tools, torx sockets/bits, engine support bracket, torque wrenches, honing tools, ring compressor, Bentley Manual, and injector ring tools. Plus I had a pretty good variety of tools but if not I would have had to buy them. In the middle of the job I got a digital torque wrench that does lbs/newton meters and angle. The angle feature was so nice to have.
Expect some problems- When I was all done and celebrating the engine running again I was hit with an overheating problem. I tried over and over several times shutting it off when it got to 235. I was sure it was air in the system so I concentrated on burping as the solution, there were no leaks anywhere. As I was thinking about how to check if coolant was flowing through the system I could not remember if I released the tab on the water pump friction wheel. I got under the car and immediately saw that it was still disengaged. Re-engaged it and the cooling problem disappeared. Another lucky break was that when I finally got it started it would sputter and die. I had taken the intake tube off and unplugged the MAF sensor, and I told my wife at least you can see it run for a few seconds. To my surprise it started and ran pretty smooth. I realized the MAF was unplugged and plugged it back in and it died. Thoroughly cleaned the MAF and it was fixed, but it was just luck I had it unplugged when I did.
Get Organized- I bagged and labeled everything like has been suggested here, there are so many parts and pieces. Get a label maker and mark each plug as you go and especially as you disconnect, save yourself trouble later. When I plugged my unlabeled injectors in using the wrong order the first time I caused doubt that resulted in me pulling the head again unnecessarily. Big time waster.
Have fun- Learn what you can, celebrate the wins, go easy on yourself when you hit problems.