GMW GMW14724 PDF

This standard describes the materials and performance requirements for fuel and oil vapor resistant gaskets, used in automotive engine intake manifold and throttle body applications. The constructional and component features covered by this commodity standard are described in 1.1. Do not use this document for applications outside the Scope and 1.3, of this standard.

Material Description. Materials covered by this specification are divided into Classes and Types of oil and fuel resistant elastomers. Table 1 describes the Class (A, B, etc.,) of elastomers meeting the designated temperature range, and Type 1 and Type 2 meeting the designated application (gasoline or diesel engine). Part performance requirements are in 3.9 and Table 4B, Table 5B, and Table 7. See remarks in 1.4 through 1.4.3.

The following material types were moved to other specifications.

• Ethylene Propylene Diene Monomers (EPDM) in Coolant to GMW14747, Type E and Type F.

• Hydrogenated Nitrile Butadiene Rubber (HNBR) for coolant applications is specified in GMW14751, Type B.

• Production and service parts using these material types for coolant ports shall use the General Motors Worldwide (GMW) standards.

Part Constructions. Construction usage code letters that apply to this standard are listed in Table 2. 1.

Code letters designate specific tests that apply only to that construction and/or material for detail drawing specifications. See Section 8, Coding System.

Symbols. Plastic and rubber parts shall be marked with a symbol to designate the type of material from which the part was fabricated for the purpose of collection and handling of parts for recycling.

Elastomer Marking Symbol. Mark rubber parts weighing more than 200 g per GMW3116.

For Example:

• Fluorocarbon >FKM<.

• If practical, place the part number, the company Rubber Manufacturer's Association (RMA) code, cavity number and mold date (month/year) on the part. Characters shall be visible, and not in a location that adversely affects form, fit, or function.

Plastic Marking Symbol. Mark plastic parts weighting more than 100 g per GMW3116. For Example:

• Polyamide with Glass Fibers >PA-GF30<.

Applicability. See Table 1. Only parts fitting the scope and application may use this specification.

Remarks. Approved compound properties for each type of elastomer are listed in Tables 4A, 4B, 5A, 5B, 6A, 6B, and Table 7. Table values by type are a compilation of data from multiple approved compounds and hardness ranges.

Plastic carrier (Cp) gaskets with coolant ports, require heat and hydrolysis stabilized nylon per GMW16270. Gaskets without coolant ports may use heat stabilized nylon per GMW3038. See Table 2.

Fluorocarbon (FKM/FPM) polymer types, in methanol and ethanol diluted conditions, the percent fluorine level is most important. In biodiesel diluted conditions with oil, the cure type and no metal oxides take precedence over percent fluorine.

This global standard was developed with careful consideration to cost containment, legal considerations, best practices, lessons learned, etc., to establish consensus material quality and performance. Because this is a global standard, the supplier is only required to generate data for the initial approval, avoiding numerous regional and divisional requirements and expense.