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Piston Ring Set – Fits Yanmar 1GM10, 2GM20, 3GM30 Marine Engines (Replaces 721575-22500)

$52.95

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Delivery and Shipping

Orders are typically processed within 1–2 business days.

U.S. orders usually arrive within 6–15 days, depending on stock location and destination.

International delivery times may vary due to customs processing.

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If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This aftermarket Piston Ring Set provides a complete solution for servicing single pistons in Yanmar Marine Diesel Engines, including the 1GM10, 2GM20, and 3GM30 series (8–30 HP, 4-Stroke) from 1982 and later. Designed to meet OEM specifications, this set ensures reliable compression and oil control for restored engine performance.

It serves as a direct replacement for Yanmar part numbers 721575-22500 and the older, superseded part number 705311-22500.

Includes a complete ring set for one piston: one compression, one wiper, and one oil control ring.
Designed for a standard (STD) 75 mm cylinder bore.
Engineered for internal installation in compatible marine diesel engines.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number	Superseded By	Notes
Yanmar	705311-22500	721575-22500	Older part number

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This component is compatible with the following Yanmar marine diesel engines.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Yanmar	1GM10	8	4-Stroke	1982 and later	721575-22500	Replaces 705311-22500
Yanmar	1GM10-YMI	8	4-Stroke	1982 and later	721575-22500
Yanmar	1GM10C	8	4-Stroke	1982 and later	721575-22500
Yanmar	1GM10L	8	4-Stroke	1982 and later	721575-22500
Yanmar	1GM10VE	8	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20	18	4-Stroke	1982 and later	721575-22500	Replaces 705311-22500
Yanmar	2GM20-YEU	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20B	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20C	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20C-YEU	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20F	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20F-YEU	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20FC-YEU	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20FVE	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GM20VE	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GMLP	18	4-Stroke	1982 and later	721575-22500
Yanmar	2GMLP-C	18	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30	27	4-Stroke	1982 and later	721575-22500	Replaces 705311-22500
Yanmar	3GM30-YEU	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30B	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30C	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30C-YEU	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30F	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30F-YEU	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30FC-YEU	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30FVE	27	4-Stroke	1982 and later	721575-22500
Yanmar	3GM30VE	27	4-Stroke	1982 and later	721575-22500
Yanmar	3HM	30	4-Stroke	1982 and later	721575-22500
Yanmar	3HMF	30	4-Stroke	1982 and later	721575-22500

Technical Specs

Product Type: Piston Ring Set
Installation: Engine Internal Component
Fuel Type: Diesel
Material: Steel/Cast Iron
Bore Diameter: 75 mm
Ring Size: Standard (STD)
Product Dimensions: 18.0" L x 14.5" W x 1.0" H

What’s in the Box

1 x Compression Ring
1 x Wiper Ring
1 x Oil Control Ring

Installation Notes

Ensure the engine is off, cool, and disconnected from its power source before starting.
Drain the engine oil and coolant completely.
Disassemble the engine to access the pistons, which typically requires removing the cylinder head and oil pan.
Carefully remove the old piston rings using a dedicated ring expander tool to prevent scoring the piston.
Thoroughly clean the piston ring grooves to remove all carbon buildup and residue.
Install the new rings in the correct order (oil control, wiper, then compression) and orientation as per the engine's service manual.
Use a ring expander tool for installation to avoid distorting the rings.
Stagger the ring end gaps according to the manufacturer's specifications to ensure a proper seal.
Generously lubricate the new rings, piston, and cylinder wall with fresh engine oil.
Reassemble the engine, tightening all fasteners to the specified torque values.
Refill the engine with the correct grade of oil and coolant.
Start the engine and check carefully for any leaks, unusual noises, or performance issues.

Troubleshooting & FAQ

How do I know if this ring set fits my engine?

This set is specifically for a 75 mm standard bore size. Check your engine model against our compatibility table and verify the required bore size in your engine's service manual. It is designed for Yanmar models like the 1GM10, 2GM20, and 3GM30 series.

What are the signs of failing piston rings?

Common symptoms include excessive blue or white smoke from the exhaust, abnormally high oil consumption, noticeable loss of engine power, and poor results from a cylinder compression test.

Is this a standard size (STD) ring set?

Yes, this is a standard (STD) size piston ring set for a 75 mm cylinder bore. It is not an oversized set intended for cylinders that have been bored out.

Can I reuse my old piston rings during a rebuild?

No. Piston rings wear down and lose their elastic properties with use. They are considered a single-use component and must be replaced with a new set during any piston service or engine overhaul to ensure proper function.

How often should piston rings be replaced?

There is no fixed service interval for piston rings. They are replaced as needed during a major engine overhaul, which is typically indicated by high engine hours, significant performance loss, or specific symptoms of ring failure.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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Piston Ring Set – Fits Yanmar 1GM10, 2GM20, 3GM30 Marine Engines (Replaces 721575-22500)

Worry-free returns

Delivery and Shipping