Piston Ring Supplier

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James and All,

No apologies necessary I appreciate all the information, never to much.

Here is an overview to all of what I have going on. I am confident the rings are not original because they appear to be Chrome, Numbers 1,2,4,5,and 6 have two part oil and compression rings but #3 has a 4 part oil ring.

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Here is a photo of the typical oil ring setup. The Depth of the oil rings and compression or top rings are all are about .012. I measured earlier with a different tool and thought they were closer to .010 so I apologize but the new micrometer I am using is more accurate.

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another view of the oil ring.

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The depth of the groove into the piston is .0156.

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Here is the gauge close up after measuring the groove depth.

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The oil ring groove height is .0188

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Here is a picture of the 4 part oil ring.

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Oops actually here it is.

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I put the oil ring with its spacers together and got .0183

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or .0181

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The Compression or upper rings were exactly the same. The groove measured .0126 to .0128

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Okay that looks a lot better. Standard 1/8″ thick compression rings are .150 thick, so a .156 ring depth indicates the pistons were designed for standard ring wall. There just needs to be a small clearance between the inside surface of the ring and the piston groove so the ring floats in the groove as the piston cocks slightly in the bore. Your pistons look like they are in very good shape, presumably pretty fresh.

As I mentioned in my email, I have 16 unused 3.5″ standard bore plain compression rings that would fit if you want them. I also have 8 chrome taper face top rings if you want them. I bought them and didn’t use them in my Pierce.

I have been running chrome taper face top rings, Type 70 scrapers in #2 and #3, and chrome face 3 segment oil rings in my ’36 Packard for 20,000+ miles now. The antique piston ring suppliers often supply plain compressions and oil rings because they are easy, available, and have no issues with seating and quick break in. They have no issues with break-in because they wear easily and wear out quickly, so the rebuilder won’t come back at them with seating issues on fresh rebuilds.

Years ago Egge supplied all plain compressions for my Packard even though the original configuration was plain #1, type 70 scrapers in #2 and #3. 1930’s Pierce used the same. The rings they were supplying were stock for Allis Chalmers tractors that had a choice of plain or chrome.

I mentioned Grant because I wanted to go to an “inside bevel” chrome top ring on my Pierce and they had them long after the other suppliers ran out of stock. That is why I have left over chrome taper face. The other suppliers still have chrome taper face which is better than plain but not as good as inside bevel at oil control.

Type 70’s for the #2 groove and 3 segment oil rings should be easily found if desired.

Since the engine appears to not have many miles on it since rebuild I fully understand the desire to only replace what’s broken – my usual philosophy, but just to make life more complicated it looks like you have some alternatives if you want.

Jim

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