Getting ready to resume the rebuild of the mighty F155, but noticed something interesting about the new piston rings... Or is it nothing? (2 Viewers)

[Reeve Kook]

Hello all! After having the naked block sitting in a box trailer for a year or two now, I finally have the time to resume since I am in my senior (final) year of high school.

I was inspecting the new pistons which are 0.20" oversized that I had bought over a year ago and I noticed that the oil control rings, well one of the two that is, are different from what I pulled out of the block. The stock setup had a 1st, and 2nd compression ring, then 2 cast iron oil control rings to follow. But the new rings have 1st and 2nd compression rings just like stock, but a waffle ring for one oil control ring, then a cast iron ring for the next oil control ring. I thought it was odd, but I am sure I am just getting worried over nothing. This is my first *real* engine rebuild though, and I'm sure you know how that is. You're questioning every little thing to make sure it is perfect.

Assuming it isn't an issue though, in what order would the oil control rings go? I am assuming it goes 1st compression ring, 2nd Compression ring, waffle oil ring, and then cast iron oil ring since the bags the rings came in are labeled 1st ring, 2nd ring, 1st oil (waffle), and 2nd oil (cast iron). I have posted a photo with the new rings in that exact order on my hand and the old rings on the piston in case you cannot picture what I have typed.

Ignore the bird, she is just supervising.

 

[middlecalf]

Yup, as you’ve noted. Be careful installing the solid cast oil ring (it gets installed first since it’s the bottom ring), they dislike a lot of out-of-plane flex and can snap. Use a good p-ring install tool.

 

[Reeve Kook]

Yup, as you’ve noted. Be careful installing the solid cast oil ring (it gets installed first since it’s the bottom ring), they dislike a lot of out-of-plane flex and can snap. Use a good p-ring install tool.

I figured as much, definitely seems like very brittle cast iron. I will also be investing in a good pair of piston ring expander pliers. Thanks for the quick reply!

 

[65swb45]

There are two different ring thicknesses on the F engine. I have the variant written down somewhere. One iteration is half a millimeter thicker than the other IIRC.