Genuine Mazda MX-5 Miata Valve Stem Oil Seal

Mazda MX-5 Miata Valve Stem Oil Seal Parts and Q&A

• Valve Seals
  L807-10-155
  Q: Can broken Valve Spring, Valve Spring Retainer and Valve Stem Oil Seal be replaced without removing the cylinder head on Mazda MX-5 Miata?

  A:

  Defective valve stem seals and broken valve springs can be changed without having to remove the Cylinder Head and only with a few special tools and a source of compressed air. In case of the absence of compressed air, a nylon rope of a certain length could be used to ensure the valves do not fall into the cylinder. Start with the removal of the Valve Lifters of the faulty valves, and make sure that they are placed back in their correct positions. Disconnect the spark plug of the affected cylinder, and in case all the valve stem seals are to be replaced, remove all the spark plugs. Spin the crankshaft until the piston in the affected cylinder reaches Top Dead Center on the compression stroke, do one cylinder at a time as per the firing order. Install an adapter into the spark plug hole and hook an air hose to a source of compressed air and spray the compressed air into the engine to maintain the position of the valves. When it is nylon rope, it is necessary that the piston be positioned about 45 degrees, before TDC, feed the rope up the combustion chamber, and make sure that the end is exposed to be removed. Turn the crankshaft until a slight resistance is met, and insert clean shop rags in any holes of the cylinder head to enable the parts not to fall into the engine. Compress the spring with a valve spring compressor, dislodge the keepers then the spring retainer and the valve spring then mark the highest point of the valve spring which will be lined up later. Measure the depth of the valve stem oil seal to the upper side and remove it. The cylinder head might require removal in order to carry out additional repairs in case the air pressure is not able to maintain the valve close. Tie a rubber band or a piece of tape to the upper part of the valve stem so it does not fall and remove the pressure of air. Check the spring of the valve and stem; and, when there is no binding in the guide, check it again. Once again apply air pressure to hold the valve in the closed position, lubricate the valve stem and fit a new oil seal to the given depth. Install the spring on top of the valve making sure that it is installed properly, followed by installing the valve spring retainer and putting the keepers in place carefully. Take the pressure out of the spring tool, unscrew the air hose, and take the adapter out. Lastly, it is possible to install the Camshafts and the remaining parts in a reverse order, start the engine, and make sure that there are no oil leaks and that there are no strange sounds.