The piston rings in your car's engine are responsible for controlling oil pressure and regulating engine oil consumption. Worn or damaged engine rings will usually lead to a myriad of problems, and will require an engine repair. Here are some of the warning signs that could mean your vehicle has fried piston rings.
Common Symptoms of Damaged Piston Rings
Problems with your car engine's piston rings often display symptoms or signs that are similar to other problems with low compression in a vehicle. While the following symptoms are not always attributed to faulty piston rings, they are a good indicator that you should check the rings for wear and to see if they need to be replaced. Here is a list of the most common symptoms for bad piston rings:
- White or gray exhaust smoke
- Excessive oil consumption
- Low power for acceleration
- Overall loss of power or poor performance
If you believe your vehicle has faulty piston rings, or if your vehicle is displaying any of the above mentioned symptoms, you will need to have a compression test run on your car's engine. A compression test involves removing one of the spark plugs from your engine and trying to start the engine with a compression gauge attached to the cylinder where the plug has been removed. You can purchase a compression gauge and do the test yourself, or you can take the vehicle to a certified mechanic for an engine diagnosis.
Related Questions and Answers
What's the Difference Between a Valve Seal and Piston Ring Leak?
Each cylinder consists of three major parts: the intake and exhaust valve seals; the cylinder and piston which contains the seal piston rings and the wrist pins; and connectors to the crankshaft. When you notice performance fall away, you must have a pressure test done to the engine to determine whether the leak is at one of the valve stems, (they are constantly opening and closing and eventually wear out) or at the piston rings. The test will reveal where the leak is occurring. A seal piston rings leak is a lot more complicated to handle because you not only have to take the valve covers off, you then have to take the valve and manifold assembly off. As well as unbolt the top half of the block so you can expose the pistons and, using the right tool. (It looks something like a big set of tongs with a torque increasing handle.) You remove the piston ring or rings, (try using Gapless) and then put things back together. If everything looks promising, re-torque the upper cylinder block, reset any valves and their lash, re-gasket the valve covers, re-torque, and you are all set.
Are Cast Iron Piston Rings Less Likely to Have Issues?
If your engine's manual calls for stainless or a different metal as cast iron piston rings, it pays to follow the engine's manual, because they are the ones who have tested rings at various loads. Because today's engines run at such high temperatures, cast iron piston rings will become brittle more quickly. That's never a good idea, as they can easily deform, score the cylinder wall or break entirely. Also, their heat transference rate is different than what might be called for in your engine. So while it may work for a while, in the long run it's not a good idea.
Can You Replace One Ring, or Do you Always Need to Replace a Full Set of Engine Piston Rings?
If you notice your car's performance falling away, and suspect that you have problems related to engine piston rings, you will have to run a pressure test on each cylinder to see if there's a valve or ring leaking, since both interact. Let's say your car is a four-cylinder and that a pressure test shows three pistons are about 225 (just as an example), but the fourth cylinder is a 135. Right away, you know you have an engine problem. If you want to try something a little daring, you can try replacing the piston rings in valve four. If this is the way you go and then a new pressure test reveals that the first three pistons suddenly shoot up to 275, and the fourth stays at 225, it would indicate that you have to replace all of the pistons rings in the engine; which is the correct answer anyway.
What are Gapless Piston Rings for?
Gapless piston rings, trademarked by Total Seal, are double action piston rings. Piston rings seal the piston to the cylinder wall so that an airtight bond is formed for the fuel/air mix to be fired and power the car with no combustion escaping by the seal. Normal pistons consist of a single ring that slides into a gallery near the piston crown where it becomes a solid mass for a time. The ring is actually a round of piece of metal with a slight slit so it can fit into the gallery. Over time, the slit opens. Gapless rings are built in two parts; one, the normal ring; the second, a locking mechanism with a flange. They keep their shape no matter how much wear you put on them. Normally wear is about two percent before performance starts to fall off due to blow-by. Blow-by is a combustion product that gets by the rings and can foul the oil. The flange on half of the ring helps keep the piston ring circular and keeps blow-by down. It retains the roundness and keeps performance up. Usually, gapless rings are used in racing where engine tuning is important. In standard use, this will actually help your engine work better longer.
Do You Have to Use Matching Piston Rings in a Set?
Well, it is quite possible a piston rings set will work, if you use the same sized piston rings, even though two different manufacturers may make them. It is also true that you will have to not only increase the size of the cylinder, but also the rings - which provide the cylinder with the seal needed to make sure your engine works correctly - when you bore the engine. However, for safety sake, while you can use it the same, say 6-inch ring size, in your car's engine, you may find that rings made by two different manufacturers are slightly different and may present wear problems.