Engine Intake Manifold and Throttle Body Gaskets
|Publication Date:||1 February 2021|
Note: Nothing in this standard supercedes applicable laws and regulations.
Note: In the event of conflict between the English and domestic language, the English language shall take precedence.
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 Tables 5, 7, 9 and Table 13. 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 GMW standards.
Construction usage code letters that apply to this standard are listed in Table 2.
Code letters designate specific tests that apply only to that construction and/or material for detail drawing specifications. See Section 8.
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.
• Fluorocarbon >FKM<.
• If practical, place the part number, the company Rubber Manufacturer's Association (RMA) code, cavity number and mold date (mm/yr.) 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.
• Polyamide with Glass Fibers >PA-GF30<.
See Table 1. Only parts fitting the scope and application may use this specification.
Approved compound properties for each type of elastomer are listed in Tables 4, 6, 8, 10 and 11. 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 Behavior in Fuel Diluted Oil.
For methanol and ethanol fuel diluted oil conditions, fluid resistance improves with fluorine level, regardless of cure type (bisphenol or peroxide). For biodiesel fuel diluted oil conditions, peroxide cured FKM is preferred over bisphenol cured FKM, because the metal oxides needed for bisphenol curing, usually calcium hydroxide and magnesium oxide, can react with biodiesel fuel byproducts. These metal oxides have no significant impact on peroxide cured fluorocarbon. There is no impact on color choice, as either carbon black filler or mineral filler may be used. Other metal oxides, such as ceramic type mineral systems, are used successfully in mobility systems where zinc, calcium or magnesium oxides would not be successful in that application.
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.
Compression Stress Relaxation.
Per GMW17113, deflection is 15% for manual and continuous. Note that only one (1) method, manual or continuous, must be run. Only one (1) method is required not both methods. For manual, there is the option of running 35% deflection in addition to the required 15%. 15% deflection replicates Least Material Conditions (LMC), and 35% replicates Most Material Conditions (MMC).
Thermal Cycle Continuous Compressive Stress Relaxation, 15% deflection, GMW17113 BC6AD0.
Required test for all classes, all types with TR10 at or below -25 °C in addition to testing described in 1.4.4.