Designing Head Gaskets at Federal-Mogul is no Easy Task

For every Payen® head gasket, there are a myriad of factors which must be taken into account when designing the product for each and every application.

Engine architecture, clamp load ratio, combustion pressure limitations, available surface area, thermal stresses and the degree of deformation in the engine at peak operation, all make engineering and constructing head gaskets extremely complicated.

The head gasket sits between the engine block and cylinder head amongst significant pressures and variable surfaces. Thus, it must be specifically designed to provide a compressed seal to ensure that coolant and engine oil do not leak into the cylinders.

Range Overview

The Payen range comprises over 1,725 cylinder head gaskets. Over the last two years, there has been an increase in sales of over 200 newer designs. This is set to rise over the coming months and years for models such as the Audi A3 and the Vauxhall Corsa. Despite these increasing sales figures, the old classics still sell well, although steadily slipping down the Pareto listings as the car parc changes.

Making the Right Choice

Have you ever wondered how major engine manufacturers determine which head gasket technology is the right choice for their latest engines? The process of developing a new head gasket involves hundreds of hours of research and development work, as well as extensive customer input and electronic analysis to identify the engine’s unique characteristics and operating demands. Only then can Federal-Mogul engineers begin to piece together the complex puzzle that ultimately becomes a Payen head gasket.

Paul Saunders, Director of Aftermarket Engineering in Europe explains, “Very few engines are truly alike – each application represents an array of unique operation and design parameters that place corresponding demands on the head gasket”.

Different Engine, Different Gasket

The design process begins with an intense focus on the gasket’s operating environment – the engine’s physical design and architecture.

The following factors are taken into consideration while designing:
• head and block material, displacement, fuel type and injection method, use of a turbo or supercharger, cooling system design, number of head bolts and target clamp loads;
• key operating parameters, such as maximum power and torque, peak firing pressure and temperature, amount of head lift and bore distortion; and
• required gasket thickness and head and block surface finishes – including casting waviness, flatness and porosity.

The margin for error in each of the above is so tiny that the smallest imperfection can have significant effect on the life of both a gasket and an engine.

Layered Steel

A majority of head gaskets for the OE market feature multi-layer-steel construction combined with several design features that address the engine’s precise operating characteristics. Federal-Mogul engineers determine how many functional layers of full-hard stainless steel are needed to provide both the desired compressed thickness (key to ensuring correct compression ratio) as well as the necessary “spring” action to accommodate head lift.

Other key decisions include the configuration and thickness of the combustion “stopper” layer – which prevents gasses from escaping the combustion chamber and/or damaging other areas of the gasket body – and which types of coatings will be used on each gasket layer to ensure trouble-free combustion and fluid sealing.

Testing

Behind each Payen head gasket – regardless of its intended market – is the most extensive testing in the sealing industry. Dedicated technology facilities include dozens of engine dynamometer labs and other highly sophisticated engineering tools necessary to prove that each Payen head gasket “performs under pressure”.

For more information, please contact your local FPS Representative.

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