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Valve stem seals have been used for the various valve stem application of automotive engines by establishing the certain lubricating status between valve stems and valve guides. It is necessary that valve stem seals have stable controlled oil leakage characteristics relative to variables such as oil viscosity, shaft speed and shaft surface roughness. The practical aspect of the characteristics of the controlled oil leakage on valve stem seals for engine application in small size U.S. and Japanese passenger cars have been discussed in this paper.

According to the 1982 Japanese Engine Data Book, 249 automobile engine models are used, including gasoline and diesel engines. Among them, 87 models (approximately 60% of all 4-cycle gasoline engine models), are designed for small passenger car applications, with displacements between 1.51 and 2.00. This paper will highlight the area such as Seals for Automobile Engine Applications, Present Automotive Engine Seal Situation in Japan and Countermeasure Activity for Field Claims.

It is clear that excessive lip wear is one of the origin of oil seal leakage in the market. In this paper, follows are discussed; Oil seals used for the rear side of automotive mission gear case have excessive lip wear as typical failure mode, and the sealing characteristics of oil seals is influenced by reciprocating motion of rotational shaft with rough surface.

Types of boot seals for rack and pinion gear of automotive steering and their characteristics are given, and necessary items for designing seals are clarified based on experiments and experiences upon required performances of products.

In order to improve the reliability of oil seals in practical use, it is considered that further basic investigation for maintaining good sealing characteristics of seals are necessary. However, the result of analysing phenomena in oil seals which has caused the oil leakage in the market shows that about 60 % of oil leakage is caused by the seal installation to housing bore or shaft, about 30 % thereof by unsuitable operating condition and remaining 10 % by the design of oil seals. From the point, oil leakage troubles and their countermeasures on oil seals for automotive application are discussed.

A new SAE Recommended Practice for automotive water pump seals has been proposed through committee work. The existing standards, specifications and other publications have been reviewed to find practical information on the design and use of water pump face seals. The paper presents the committee's recommendations on types of seals and materials, design data, and qualification and inspection information. The paper also describes test methods, equipment and system orientations for evaluating seal performance.

It becomes clear that the suction coefficient of oil, K, and the sealing characteristic constant, Φ (=fG-1/3), are closely connected with the rubbing surface state of oil seals. And, investigations have done on K-, Φ-value, etc. in oil seals after the practical use in automobiles and the results have been compared with the test results in the laboratory.

From the analysis of observational results of the many dust cover seals to be used on passenger cars, it has become clear that the control of the seal design functions such as the working envelope (space available for seal side-wall), the contact face load of the sealing lip, the axial rebound load by the side-wall component, and the anti-ozone property of side-wall materials are necessary to maintain the sealing performance, and that the present dust cover seals satisfy needs requested by the costomers. Therefore, these characteristics should be sufficient when considering the designing of the seal.

It is well known that the low-temperature test is successful for rating sealing characteristics of oil seals. Therefore, a compound with good thermal resistance to an ambient temperature range from -40 to +150°C is needed by the oil seal industry and should be developed. On the other hand, it is indicated that low temperature affects the sealing characteristics and the lip abrasion of oil seals. This paper examines the relation between temperature and the sealing characteristics of oil seals. It is clear that the condition of the rubbing surface is closely related to the sealing characteristics of oil seals, and that the lower the ambient temperature falls, the rougher their rubbing surfaces become. Moreover, the roughening condition of the rubbing surface is intimately related with the environmental temperature, the rubbing period, the lubricating condition, the lip design, and compounds.