deboatmon

Overhauled pair of 502 EFI's and apparently rings on one motor did not seat for squat ! Starboard motor has vapor out breather and is leaking several places. Motors are built pretty much to 500 EFI specs regarding parts and with all good parts from top to bottom. They have run well for several years. Recent overhaul has been disaster though. One motor fine, one leaking (puking) oil everywhere.

I did the recommended, typical procedure for seating rings and used non synthetic oil. Motors have about 35 hrs now on last rebuild.

It's been suggested that I try a non synthetic, 20-40 diesel motor oil that contains zinc and it's been said that there is a small chance that this might help to possibly seat the rings. I typically run Allysin 20-50 synthetic oil and have for 10 years with zero problems. Motors have a total of about 1050 hrs since new. Bored + .0030 right now.

Anyone have any wise suggestions they would care to share with me about this ?

deboatmon

NOPUN

when I was a kid we broke the motors in with straight 10wt motor oil. Ran it for 500mi then changed it to what ever we intended to run for life. never had anything not seat rings, worth a shot anyway
The zink thing is more for breaking in flat tappet camshaft more than ring seating. After the cam has gone thru it heat cycle and hardend you can run motor oil that has a light zinc/or no zinc content.

Griff

If they didn't seat in the first hour they are not going to. The cylinders are probably polished.

Donzinator

I'd say Griff's right, if they didn't seat right away they're not going to.
What I have used for break-in oil is any mineral oil. Regular motor oil (excluding synthetic) is ashless-dispersant and has chemicals to keep deposits from forming inside the engine, unfortunately this also keeps the rings from seating. Straight mineral oil doesn't have these chemicals and allows the rings to seat.

Panther

What stone did you use to hone the cylinders? Cross-hatched? What Rings? What's piston-wall clearance now? did you run new pistons? What ring gaps did you use?

Puking oil, where and how? You saying you have blow-by?

ezstriper

most all new rings are very specific on cyl wall finish, had a 509 that did the same thing last year, don't know what the builder did not do right, engine ran fine, saw no issues, till I pulled the heads to mill them...saw it then...

CSCinc

Stop wasting time and jus pull the motor and check whats going on. Its not going to fix itself. If the rings werent seated in 15 minutes there not going to seat.