I'm in the process of replacing the rings in my Gen2 N12 R56 2007 mini cooper (non-turbo). Rings P# 11-25-566-479-BOE

My problem is that I'm not able to get the oil ring (or oil scraper ring) to compress down enough for the piston to drop into the cylinder. I've had replacement rings sent because they appear to be oversized at 3 1/8th inch versus the 3 inch diameter of the cylinder.
When I put the oil ring into the cylinder, just like you do the regular ring to check the gap, it will not fit "level" or it has to sit offset within the cylinder or literally overlapped.

Is the problem with me or the oil ring? I'm using the ratcheting tool with the 2 5/8" to 3 1/8" sized compression attachment.

Thank you for your time!
Mike

 

The problem is with the way you try to insert the piston into the block. I check realoem and this is the correct part number.

The rings are slightly bigger so when they expand they provide a tighter seal.

When i did mine, it was frustration and time consuming...there is no easy way to do it other than to be patient and make sure the ring compressor is actually compressing all the way around.

im pretty sure you watched YT. just watch again and take your time.

 

Best of luck ---

 

Sounds like you have some file-fit rings that need the gap set as Michael2007Mini says.

 

I was finally able to get the piston to drop into place. Boy what a pain in the butt. Since I could not get the ring compressor to fully collapse the oil ring I had to install in manually. I had to tilt the piston a bit to get one side to hold while manually pushing the oil ring into position. Once the oil ring was completely pushed into the piston and cylinder I was able to use the ring compressor to finish compressing the top two rings and the piston dropped right into place.
Not sure if this will help anyone but I sure would like to know what ring compressor others had used and if they had the same issues that I had with the oil ring.
btw, I did check out the ring grooves and made sure they were clean before this last try.

Thanks to all who replied, greatly appreciated.

 

Thanks for posting your outcome @michael2007mini. I'm currently in exactly the same situation and just walked away from it to clear my head. Can you confirm everything worked out OK for you? Did you only replace one piston or did you have the same issue with all of them? I'm on my first and it's pissing me off. Youtube makes it look oh so simple but the oil ring keeps popping out on me. It's my first time doing this, but it looks so much simpler than what I'm currently experiencing....

 

It ended up being technique for me. I used the spring steel ring compressor that you see everywhere. Got mine from HF. Piston in, with the ratchet nut facing up. Everything nice and oily. Tighten it as tight as it can get and slide it down until the piston skirt is 1" clear of the steel sleeve. Put the sleeve in the cylinder and tap the top of the steel sleeve with the rubber handle of a hammer to ensure everything is perfectly straight, and the bottom part of the sleeve is in complete contact with the block. Try to tighten it another click. then lightly tap the piston and then tap all around the top of the sleeve again. Rinse and repeat rotating between the top of the sleeve and the piston using the rubber handle. I ended up tapping the edges of the piston on a couple to get them to go.

 

Good to hear CantComplain. Sorry for the late response but glad you finally got it figured out. Between all the posts on this issue hopefully the next person shouldn't have any problems. If you could, post a picture of your ring compression tool if you don't mind.