I am in the process of rebuilding my engine and I have run into a problem. I ordered Mahle piston rings, P/N 11 25 7 566 479 , and I am running into an issue with the oil ring not fitting. It is the 5-ring set (I believe that is all you can get now) and the piston rings are 1.20mm (top), 1.50mm (middle), and 2.00 (bottom). When I put in the two scraper rings, the separator(?) ring will not fit between them. I have checked for other ring sizes and I cannot find them at the moment. I checked RealOEM and the part number is correct and there is no other P/N or ring size listed for my engine. Build date is 01/2009. Am I missing something or doing something wrong? I didn't have this issue with my M54 rebuild in my e46, but that's a different car/engine. Has anyone else run into this issue?

Thanks!

 

I could be wrong, as I haven't installed Mahle rings before, but I believe the center ring goes on first, then the two top and bottom scraper rings.

So they get stacked up like this:

 

That’s exactly how they install. I went back out to the garage after posting, inspected the rings, and noticed the raised portion on the inside of the middle piece. I then deduced that it needed to go on first so that the scraper rings hold it in place.

I like the diagrams and thanks for the excellent reply!

Now that that’s out of the way, I have another question: what’s the best way to install all of said rings? I saw a thread on this but the explanations were a little muddy. I believe they were trying to explain it like this:

1st/Top ring is oriented at 10:30 with the split facing 45 degrees off of the front of the engine/direction of the arrow on the piston.

2nd/Middle ring is oriented at 1:30 with the split facing 45 degrees off of the front of the engine, or 90 degrees from the 1st ring.

3rd/Top Scraper ring is oriented at 7:30, with the split 45 degrees off of the back of the engine.

4th/Spacer ring is oriented at 6:00, with the split facing the rear of the engine.

5th/Bottom ring is oriented at 4:30, with the split facing 45 degrees of of the back of the engine, or degrees from the top scraper ring.

Is this correct?

 

I’ve always heard that you want rings gaps to be 180° out of alignment. Not sure if overall orientation to the connecting rod or engine matter as much…

 

I had heard that as well. I did that on my e46 engine without issue, but that only had 3 rings. The info I have above I got from Summit Racing and it mostly matches what I found on the Mini2 forum (where the info was a little muddy).

Just wanted to see what other people’s experiences were, especially those who are more experience in rebuilding these engines.

 

Okay, now the fun of getting the pistons in is taking place! What ring compression tool is a good one to use? I have a band-clamp style from when I did my e46 engine rebuild and had no issues, but am having issues with the Mini piston rings. The following occurs:

The tool isn’t able to evenly compress the rings, so it’s not able to compress the rings enough to get into the bore. The other issue I see is that the scraper rings are thin and “pop” out in the transition from the tool to the bore, preventing any further insertion.

I was looking at the conical style, which seem to have good ratings, but unsure as to exactly which one I need. Some places I see bore size at 77.0mm, others say 77.5mm. Should I just go with the 77.0mm? What do others use?