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
An old tractor engine man told me he would quick seat a difficult engine by putting a fair amount of Bon Ami in a cloth and dusting it in front of the carb. He claimed just enough abrasive going in would seat the rings and not hurt the engine. I have never done this, but found it an interesting idea. - Randy
You guys are right on the ball. As to the oiling system, two solid streams of oil delivered through a 3/8-inch pipe are shot out over the connecting rods. Talk about overkill. That's probably why all the journals are nearly perfect. And that's not the first time I've heard of using Bon Ami, or baking soda, delivered through the carb. - Craig
Please go easy with the Bon Ami stuff, guys. While this used to be an accepted way of quickly seating in an engine, it is also a very quick way to destroy an engine and should only be used as a last resort. In older engines with low piston speeds it was marginally workable. The abrasives were typically used to resolve compression issues, not oil consumption issues. It sounds like you have plenty of compression - oil wiping is the prevailing issue. Remember that abrasives counteract the lubricants in the engine. If you have never done the Bon Ami thing, try it first on an engine you don't care about. - Harvey
I have seen an engine ruined beyond repair with the Bon Ami trick. - Dan
Caterpillar used to have some stuff they called 'Break in Powder' that was used to seat rings in the manner described here. I tried the Ajax thing on my 16-30 Rumely, but the results were inconclusive. Now, with more time on it, it seems a lot better.
I wonder if there wasn't something special about the original Avery bottom rings. What type of rings did you put in the bottom groove? I did a little checking in a reprint catalog and would think with five rings there wouldn't be much oil getting by. If my 25-45 has too much oil in the crankcase everything within 50 feet is covered with black spots - including the operator. - Ken
These are five ring pistons: three compression, one that holds the wrist pin to keep it from damaging the cylinder should it get loose and a fifth ring below that. Immediately below that ring is a chamfered groove with drill holes for oil escapement, sort of a substitute for a real oil ring. A friend said he has heard some rings are harder than normal and very difficult to run in. Could this be my problem? - Craig
Craig, because of the rotation of the Averys and their oiling system, all the oil goes to the front cylinders. Averys smoked when new because of what they called their oil control ring, the holes drilled in the piston next to the last ring - it never worked. I have seen bushings put in the oil lines to help with this, but that's not a good idea. Put a real oil control ring in the fifth and third land on the front cylinder and in just the fifth on the rear - and don't forget to drill the pistons under the rings. - Ed
I think Ed has the answer. These old engines were made to work with a wide open butterfly, so there wouldn't be much suction drawing oil past the rings. The first Model T's had no oil rings, but that soon changed. Break in powder probably wouldn't get to the bottom rings, where it is needed most, and I don't think a regular ring will ever control oil as well as a scraper or oil ring. Some people recommend putting an oil ring in Rumelys, but most seem to control their oil level well enough without them. - Ken
It could be the rings never seated. A long time ago I rebuilt the engine in my 1954 Ford. I put in a set of chrome rings, and after 500 miles of carefully breaking the engine in, it was smoking like crazy. The shop that did the boring job told me to really stand on it a few times to get the rings to seat. They said if I was lucky the bores hadn't glazed and this would work.
I was going to Kentucky from California the next week, so I drove over Donner Pass with my foot in it. Remarkably, going down the other side there was no more smoke. Maybe you need to hook up to a Baker fan and just load the heck out of it. Be sure to vary the engine speed and give it a rest every minute or so. - Elden
I still think I've got hard rings. Ed's rotation note makes sense. If you could see the stream of oil pouring over the rods you would not believe it! But I don't think there's an oil ring made that would cure the problem. I might lift the timing cover again and put a shield inside the crankcase to reduce the amount of oil getting thrown onto the front piston, or modify the oil delivery elbow to shoot a wider, less concentrated oil stream. - Craig
Craig, let's straighten this out. Ed and Ken hit it square on the head - until you put an oil ring in a closed crankcase multi-cylinder engine it will smoke and burn oil, period. You are looking at a prime example of early technology before they knew what oil rings were. Ever watch a silent movie and see the cloud of smoke following the old cars? They didn't have oil rings in most cases.
Rumelys without oil rings are sloppy pigs. You need an oil ring in the bottom groove and holes through the bottom of the groove to let the oil through. Do not use Bon Ami or dirt or any other abrasive unless you want to ruin the engine. There is no substitute for break-in running time. My assumption from reading the thread is that your compression is acceptable and the oil slobbers everywhere. Is this correct? I consider the lack of oil rings in closed crankcase, four-cycle, multi-cylinder engines to be a design defect. You can live with it, or fix it -.Dave
Ed is correct regarding the rotation of the engine. I had the timing cover off today and modified the oil feed to the front piston connecting rod and things have improved considerably. As I explained before, just below the bottom ring is another groove with numerous holes through the skirt. In my humble opinion an oil ring above that would be superfluous. It's strictly a matter of too much oil all the time. The rings will break in eventually when I can get it on a constant load for a while. It has great compression. - Craig
Even with the oil groove, if you want it to be dry you need an oil ring in the bottom groove with holes at the bottom of the groove, at least on the front cylinders. As I stated before, these early engines were lacking in oil ring technology. You wouldn't dream of using such a lame system as a groove with holes in it below the bottom compression ring and no oil ring in a modern engine. It does not work, period. If it did, those cost-cutting car makers would all be doing it to save 15 cents per car. You need a wide, double scraping edge that scrapes both ways.
Look at flathead Fords -same problem, but caused by too narrow an oil ring. Henry Ford insisted that 5/32-inch was wide enough for an oil ring. Well, he was wrong. When Henry got out of the shop Ford started using 3/16 inch oil rings, and they still do to this day. If you want to stop the oil burning, oil rings are the only way unless you mess with the oil flow inside the engine. Be careful that you don't cut the oil down so much that you cause damage.
Talk to Rumely owners. Without oil rings a Rumely slobbers and spits unless run full bore and under load. This despite the cylinders being angled down at the back. Early John Deere engines had the same problems. Deere had a scraper compression ring that actually came out of the cylinder a little at the back. They insisted this would scrape the oil down. It did not. I have piles of useless new-old-stock oil scrapers that will not do the job. Rumely never did wise up, and there aren't enough Averys around to make a decision on them. I think that they were doing the best that they could with what they knew at the time. - Dave
SmokStak is an engine conversation bulletin board with over 39,000 messages on file and is part of the Old Engine series of web sites that started in 1995 as 'Harry's Old Engine.' Harry Matthews is a retired electronic engineer and gas engine collector from Oswego, N.Y., now residing in Sarasota, Fla.
'Do not use Bon Ami dirt or any other abrasive unless you want to ruin the engine.'