Smokstak

Controlling Oil Rings


| January/February 2003



Smokstak

Arecent topic on the EnginAds SmokStak bulletin board at http://www.smokstak.com/ involved seating new piston rings in old engines. The thread's head? Expert Advice Needed.

I just rebuilt the engine in my 1914 12-25 Avery. The sleeves are new and I re-grooved the pistons for new, over-width step-cut rings. I also installed new wrist pin bushings, new valve stems and guides, everything. But I have a problem: The rings will not seat, and it's pumping oil like a pig even though it runs like a Swiss watch.

I started with 20/50 weight oil, switched to 10 weight non-detergent, and now straight 50 weight. I don't have the pulley mounted, but when I press a plank against the flywheel it clears right up. I've resigned myself to the fact that it's just going to take a long, heavy load to do the trick. Does anyone know of any shortcuts? - Craig

I have seen this happen in a pressure-fed engine when rod bearings are running excessive clearance, which causes excess oil to be slung from the crank onto the cylinder. I'm not familiar with your engine, and if you don't have pressure feed to your rod bearings then everything I'm saying is hog-wash. But if you do, try tightening your rod bearing clearance.

I don't know what of oil ring you are using, but if it's a simple gapped ring, make sure the gap faces the wall of the cylinder opposite from the wall that gets all the oil. If it's a compound ring, make sure you stagger all of the gaps appropriately. - Harvey

Craig, a friend of mine overhauled a Farmall H and his tractor ran great, but it pumped oil worse than before he overhauled it. I helped him tear it down and found he had put the oil ring in upside down. There were no marks on the rings, so he just put them in the way they came out of the package. It turned out the rings had a groove on the inside that had to face towards the top of the piston. After we did this it cleared right up. - Justin