Your car's engine burns a balanced mixture of air and fuel to produce power. But before the mixture is ignited, it needs to be compressed to make combustion easier. Compression is the main responsibility of the engine's pistons. The rings around each piston make sure no combustion materials escape the engine's cylinders.Likewise, these rings also keep oil in the crankcase from contaminating the mixture. A compression test would reveal a worn-out piston ring set by measuring the amount of compression produced in each cylinder. You'll need new piston rings if compression ratios fall below engine specifications.A piston usually has at least two compression rings and one oil ring. The compression rings, which are located at the top part of the piston, ensure maximum compression of the air-fuel mixture, while the oil ring prevents engine oil from seeping into the engine's combustion chambers.Keep your car's power at its optimum by maintaining its piston ring set. Carparts has complete sets readily available.
• Our piston ring sets can withstand high temperatures and pressure.
• They come complete with compression and oil rings.
• Carparts guarantees their high quality and excellent performance.
A Simple Introduction on Piston Rings
Piston rings are circular metal bands inserted near the piston heads. They are composed of two parts: oil control rings and compression rings. Oil control rings are mostly responsible for cleaning the cylinder walls off excess oil. Compression rings on the other hand mostly keep the seal between the combustion chamber and the rest of the cylinder, and it transfers heat from the piston to the cylinder wall. It is important to take note of some elements when replacing the compression springs. Picking the wrong set can greatly affect engine performance.
Assuming you are picking a set of identical rings that fit the engine bore, here are a few things to consider to filter your options.
Iron vs. steel
Compression springs can be made of either cast iron or steel. Here's a quick overview.
- Cast Iron: Old stock engines usually come fitted with cast iron piston rings. As the lowest grade of rings, these are suitable for low power engines that don't heat up as much as turbocharged engines. This is also the least expensive, so cast iron is perfect when on a tight budget.
- Steel: These rings can either be in chrome or molybdenum (moly). Steel rings are fit for powerful engines because of its high heat tolerance. It is also more durable and wear resistant compared to cast iron. Chrome or moly rings are usually used for dirt vehicles.
As a general rule, only fit cast iron rings on engines that require them as a minimum. Never downgrade from a higher level ring to a lower level ring.
Size and thickness
Remember to balance the size and thickness of the ring between the ring insert's gaps, and the optimum performance of the engine. Piston rings expand when heated. A larger ring is good in terms of sealing the combustion chamber to avoid blow-by. More metal also means faster heat transfer from piston to the engine. However, install a ring too large and it might cause extra friction and wear to the cylinder wall, shortening ring life.
Grooves and edges
The little grooves at the edge of the rings play a role in both engine compression and engine oil control. Different cuts also have varying effects on a piston's vertical uplift and heat transfer. There are styles like L-shaped, rectangular, keystone, taper, and faced, depending on the availability and compatibility to your engine. Pick the right style that fits your needs. A bad design can damage the seal and effectiveness of the engine.
Piston Rings Tune-Up
A good set of piston rings not only ensures compression in the engine, but also the cleanliness of the walls from oil. Replacing or upgrading piston rings should always be a part of any engine rebuilding process. Once the pistons are removed from the cylinders and the old rings are removed, inserting new rings is a simple process in the whole engine repair job.
Difficulty Level: Moderate
- Piston ring kit
- Expander tool
- Feeler Gauge
- Paper towel
- Engine oil
Step 1: Assuming that the engine is disassembled, remove the old piston rings from the piston. Clean the groves of the ring inserts with paper towel.
Step 2: Place the rings on the engine bore to check the rings' fit on the hole. Use a feeler gauge to see if the rings are tight enough against the bore. You can also try pushing the rings through with a piston to see the fit. Make adjustments on the ring if necessary by widening the gaps using a file if the rings are too big for the bore.
Step 3: Once the rings are ensured fit, lightly lube them with motor oil. Using a ring expander tool, place the rings on the piston inserts one at a time. Start by inserting the oil control rings on the slot closest to the bottom. Next, insert the compression rings on the middle slot, and finish by placing the top compression ring on the top gap. The rings should be labeled by the manufacturer for your guidance.
Step 4: Tighten the rings so that they won't scratch the cylinder walls.
Step 5: Use paper towel to clean the cylinder wall and the piston. Lightly grease both with engine oil before inserting the pistons to the cylinders.
Depending on whether rings needed to be adjusted, the whole process can take between 30 minutes to 1 hour.
- Do the repair along with a complete engine rebuild. It is impractical to overhaul an engine only to replace piston rings.
- When filing the rings to widen the gaps, take off small parts only to avoid overcutting. It is better to do this tedious process than end up with rings larger than the bore.