D2 5U cylinder ridge reaming

[Toby Nelson]

I am currently overhauling the engine of my D2 #5U7066 and am looking for advice on reaming the cylinder ridges for installation of new piston rings. My reamers will cut the liners without trouble, but leave a portion of the old ridge that's about .001"-.002" tall by my measurements. I believe the reason for this is that the area where the top ring reaches the end of its travel is worn in slightly more than the rest of the liner, and the reamers I have that will cut the very hard Cat liners are designed to cut a straight, vertical line, and the guides don't permit the cutter to enter the full depth of the worn area. I have an older reamer that has an adjustable depth cutter, but the liners are too hard for it to cut. If I can't get any more of the ridge out I may consider using the old top ring over again instead of risking possible damage of a new ring hitting the ridge. Does anyone have any advice on this subject?

Thanks,
Toby Nelson

[Old Magnet]

Not a great idea to leave the ridge or reuse the old rings unless they are near new. Can you locate an adjustable cutter that will handle cutting the liner material. A rebuilt engine with restored clearances will have a slightly different swept surface ring travel and you run the risk of hitting the ridge.

[Toby Nelson]

Thanks for the reply, I agree it isn't good to leave any of the old ridge. I'm looking for a suitable reamer now, but may contact the local machine shop to see if they have the tools to take care of it for me. They've done a good job with the old stuff I've sent them in the past.