Ford extols the virtues of Loctite liquid gasketing
The powerful new Ford engine is small and more highly stressed than old designs. This is a common trend and one to which Henkel gasketing products have responded. To meet the need for a flexible product to accommodate the increased vibration, Henkel recommended its Loctite 5900 silicone for sealing oil pan and front cover joints on the Fox engine, a thixotropic black paste that when cured has excellent performance in engine oils. “The Ford design rules dictate that the walls of an engine block should be a certain thickness”, explains Tsunou Chang, Ford’s Liquid Sealing Specialist. “But progress comes out of challenging traditional ideas, and our designers had proved in studies that thinner walls were do-able. But that meant the RTV process had to seal the engine with reduced wall thickness and that presented Henkel with a challenge.”
Specially developed anaerobic adhesives
Also used on the Fox engine is Loctite 5182, an anaerobic gel adhesive. This has been modified specifically for Ford’s use for sealing cam caps. Sealant beads are small on this engine it is therefore essential that the gel is dispensed accurately and bubble-free to ensure no bead breaks occur, any inconsistencies could compromise engine sealing. As a result this product is now centrifuged during the production process to prevent such an occurrence.
Loctite 5182 was also a contender for the fuel pump cover seal on the Sigma engine manufactured at Ford Bridgend. This is a new Ecoboost engine that is also highly stressed and although Loctite 5182 proved the perfect choice for the small Fox engine, tests confirmed that a flexible anaerobic sealant would be needed for the larger Ecoboost. Swift development and testing processes ensued resulting in Henkel’s introduction of Loctite 5188, its new best-in-class product for anaerobic gasketing.
Loctite RTV and anaerobic products create self-forming gaskets that provide a perfect seal between components, with maximum face-to-face contact, eliminating flange face corrosion. A low pressure seal is formed immediately on assembly, with full cure in 24 hours giving a joint that won’t shrink, crack or relax. These products are ideally suited to automatic dispensing, meeting Ford’s cycle time requirements with maximum repeatability.
Although the automatic application of the Loctite products involves similar capital expenditure to hard gasketing, it is their ongoing flexibility where substantial cost savings are found. “Engine variants have different bolt hole patterns and coolant routes with varying numbers of ports”, says Tsunou Chang. “One major benefit with RTV is that these variations can be easily programmed so that we can process different engines on the same production line. This simply isn’t viable with hard gasketing.”
Another benefit of Loctite liquid gasketing is that it will seal rougher surfaces and higher porosity , meaning that where tolerances allow, no secondary finishing is necessary. And this represents an important production cost saving. Also with the emergence of new aluminium alloys this is an important consideration as with Loctite RTV surface pitting isn’t an issue. By comparison hard gasketing carries a variety of more stringent Ford production rules with regard to surface finish and is therefore a much more demanding technology to use. Another plus point for RTV is reduced inventory over conventional gaskets.
Compression gaskets need high clamp load and tend to relax under dynamic load and decrease in thickness, resulting in loss of bolt tension in the flange joint and the potential for leakage. Loctite gasketing materials require much lower clamping forces, do not relax, and therefore maintain clamp load. This has a positive effect on warranty.
Henkel’s relationship with Ford now spans forty years. It is Ford’s preferred single source supplier of industrial adhesives and sealants for engine production throughout the world. It’s a great accolade for this manufacturer of the Loctite brand and testimony to the performance of its products. But more than that it is the result of Henkel’s characteristic focus on customer support that allows companies such as Ford to continuously push the boundaries of technology and gain competitive edge.