Customer 
In any high-performance valve stem engine, there is a small component that takes on a huge task. Engine valve seals serve as gatekeepers of the engine’s cylinder head to manage oil flow to ensure that the engine valve stem gets enough lubrication while not allowing excess oil into the combustion chamber.
When a valve stem seal gets damaged or when worn valve guides allow the valve to move improperly, you will have problems like smoky startup and electrical power loss. Whether you are replacing a worn valve seal or simply changing to high-performance valve guide seals, it’s essential to pick the right valve guide seal if you want your engine to last longer.
In this article, you will find out how to recognize faulty valve seals for the best performance of your engine.
In the cylinder head, intake and exhaust valves open and close thousands of times per minute. It is a long, narrow metal shaft of the valve called the engine valve stem. This stem keeps moving continuously upward and downward through the hollow metal tube, which is fitted into the cylinder head and called valve guides.
The engine valve stem 200 micron boundary layer involves high friction and temperature, requiring continuous lubrication. Oil is sent to the cylinder head to lubricate the camshaft, rocker arm clips and lifters, and it collects on the top of the valve assembly in the process.
This is where the mechanical difficulty starts.
This shows the necessity of a high-quality valve stem seal acting like an accurate measuring device. This valve sealing element does not keep everything dry, but maintains a small layer of oil only.
While looking for proper components, you would soon observe that not all valve guide seals are similar. It is because different cars have different sealing needs.
In the past, manufacturers followed two main types of designs:
In high-performance applications where extreme temperatures are involved, the right material selection becomes very crucial. A standard rubber seal is likely to become brittle and break under these working conditions.
When the engine valve seals become weakened, they do not remain elastic or become fragile anymore. It will now be possible for any oil that has collected to freely go down into the combustion chamber. If you suspect your engine is burning oil, look for these signs:
The most obvious sign that there may be worn valve seals in your car is a distinct cloud of blue-gray smoke exiting the tailpipe immediately after starting a cold engine.
When you turn your engine off, the oil inside the upper part of the cylinder head remains hot. With a worn valve seal, the seated oil finds its way down the stem of the valve overnight and settles on the closed valve or inside the combustion chamber of the cylinder. When the engine is started, and this accumulated oil is burned, it produces a cloud of blue smoke visible for just a short while.
If you see blue smoke while cruising down the slope or when easing up on the accelerator, it’s likely that you have bad intake valve guide seals. The act of deceleration creates a vacuum in the intake-exhaust manifold. Such a high vacuum serves as a syringe, sucking the oil down through the valve guide seal into the cylinders where it is burnt.
When your engine repeatedly uses up oil, and there are no leak spots on the pavement outside your home, your engine may be losing oil internally. An old and degraded valve seal can allow a vehicle to consume oil at the rate of more than one quart of oil between oil changes.
The steady supply of oil into the combustion chamber coats the spark plug electrodes in a greasy, dark crust known as oil fouling. This prevents the plug from generating a good spark, leading to:
It is very rare that valve seal failure occurs within a vacuum, with the majority of wear being accelerated by internal problems within the valve train.
With constant movement of the valve stem for years and many miles, wear occurs within the bronze or cast-iron valve guides.
Such wear leads to increased lateral clearance, which results in the valve moving sideways instead of maintaining its normal pattern of movement.
This side-to-side movement distorts the inner edge of the valve guide seal, making a completely new seal ineffective in a short amount of time.
Clearance measurements are important in an engine rebuild. You may assume that installing top-brand valve seals and 2000 series kits will yield good results, but without checking the valve guides for 400 series, failure may occur soon afterward. As such, it is important to make sure you do everything to install a valve guide seal of the highest quality.
The process of replacing worn seals is tedious, yet possible while the heads are still mounted on the engine block with the right procedure.
Gripping the Valves: Spark plugs are removed. Then the cylinder is pressurized using compressed air through the spark plug adapter, or a length of clean nylon rope is pulled into the spark plug opening and the piston rotated upwards to the position of TDC (Top Dead Center). It prevents the valves from dropping into the cylinder once the springs are taken out.
Spring Compression: An overhead valve spring compressor is used to compress the spring. Then the tiny valve keepers should be removed carefully using a magnetic pick-up tool. Remove the valve spring retainer and the spring assembly.
Old Seal Removal: Specialized pliers that help in the process of valve seal removal are used to grab the body of the old seal. Twisting and pulling it up prevents damage to the previously polished surface of the engine valve stem.
Implanting New Seal: Set a safeguard installation cover over the groove areas of the valve. Apply lubricating grease to the inner side of the new seal, and insert it. Fixate the seal firmly against the valve with the aid of the seal driver.
Reassemble the Valve Train: Replace the valve spring and retainer, and compress the spring. Insert the valve keepers into their casing.
At the end of the day, the engine is an entire ecosystem where little parts determine the fate of big power. If you have a worn set of engine valve seals, it won’t take long for an expensive, high-horsepower build to become a smoke-spewing oil machine.
Don’t let a tiny piece of rubber stand between you and a flawless run. Upgrade to quality sealing, combine it with good hardware, and your engine will stay powerful and clean.