Why Use Assembly Lube When Building an Engine?

When a new or rebuilt engine is first started, some of its most heavily loaded components must begin moving before normal oil pressure is fully established. Cam lobes, lifters, rocker arms, bearings and other critical surfaces therefore need protection during assembly and through those first moments of operation.

That is where engine assembly lube comes in. AMSOIL Engine Assembly Lube is formulated to cling to parts during the build, provide additional anti-wear protection at startup and remain in place even if the engine sits for weeks or months before it is fired for the first time.

Why Not Just Use Motor Oil?

Engine oil is designed to circulate once the lubrication system is operating. During an engine build, however, oil applied to exposed components can drain away long before the engine is started. Assembly lube is formulated with a high-viscosity base oil and tackifier so it stays on critical surfaces for much longer.

That makes it particularly useful when an engine is assembled gradually, stored between stages of the build or transported before installation.

Why Not Use Ordinary Grease?

Grease can certainly cling to parts, but that does not automatically make it suitable as an internal engine assembly lubricant. AMSOIL specifically formulates its Engine Assembly Lube to dissolve in engine oil after startup. This helps reduce the risk of material remaining in oil passages or contributing to deposits after the engine enters service.

Protection Before Oil Pressure Builds

At initial startup, an engine can operate momentarily with little or no oil pressure at some critical surfaces. AMSOIL Engine Assembly Lube combines its ability to cling to parts with high levels of anti-wear additives to help protect components during this vulnerable period.

It also contains rust and corrosion inhibitors, which can be useful when a newly built or partially assembled engine sits for an extended period before first start.

Where Is Assembly Lube Used?

AMSOIL recommends Engine Assembly Lube for new and rebuilt four-stroke engines, including racing and performance engines, on areas susceptible to initial startup wear. Typical examples include camshaft lobes, lifters, rocker components and bearings.

Assembly Lube Is One Part of the Build

Assembly lube protects the engine while it is being put together and during the first moments of operation, but it is only one stage of the process. Once the engine is assembled, a dedicated break-in oil can be used for the first start and initial running period before changing to the lubricant suited to the finished engine and its intended use.

See the full Performance Engine Build Lubrication Guide for the complete process from storage and assembly through break-in and final oil selection.