In an engine, 7 types of bolts out of approximately 70 are defined as Critical, that is crucial to achieving the engine's own design performance.

Having developed specific and in-depth skills  on engines, Brugola OEB Industriale Spa has specialized, throughout the years, in the production of Critical Bolts, that is those bolts dedicated to assembling an engine's vital components.

The bolt that has made us famous in Italy first and then in the World.

Type of bolt with a compact cylindrical head and hexagon socket, may be combined with a shank formed by a helical spiral which works by distributing loads on the shank itself, thus increasing elasticity.

POLYDRIVE® is the most advanced and revolutionary driving system in fasteners history,
it's the evolution of the cylindrical head bolt with a hexagon socket.

Type of screw with a special dual purpose spline-shaped drive. Given the same applied force, it ensures more compactness and excellent driving using its specific key. Used for assemblies of critical parts in very compact modern engines, particularly for installing heads.

Bolt used for fastening engine heads, they ensure a perfect gasket seal

Bolts used for fastening engine cylinder heads, usually in a number of 2x no. cylinders+2. They must exert an axial load allowing a steady contact pressure to be maintained on the head gasket, such as to ensure that cylinders are perfectly sealed and therefore avoiding pressure losses in the combustion chamber and preventing any pressurized burned gases from leaking to coolant conduits.

Bolts used for fastening bearing caps, they ensure correct operation of the engine crankshaft.

Bolts used for fastening the various components of the lower part of the engine and which constitute half of the main bearings (main bearing caps, half blocks, complete banks).

Bolt used for fastening connecting rod caps

The con rod cap bolts must be subject to at least two screwing operations during the productive cycle of the engine and must therefore be engineered to guarantee a more constant distribution of the axial load.

Bolt used for fastening flywheels or crankshaft flexplates.

Bolts used for tightening single or dual mass flywheels paired with manual transmissions, or automatic gearbox connection plates.

Bolt used for fastening camshaft caps.

Must be able to guarantee a precise axial load to counteract the forces transmitted from the lifters to the camshaft.

Bolt used for fastening camshaft and variable camshaft timing sprockets.

Must be able to guarantee a precise axial load since their purpose is to keep the gears or variable camshaft timing in perfect synchronization in relation to the crankshaft thus ensuring correct engine operation.  

Bolt used for fastening crankshafts.

Bolts used for tightening timing belt pulleys-dampers and FEAD (Front Engine Accessory Drive) accessory components. May be individual bolts ranging from M12-M16, or multiple smaller bolts, usually 4-6 to M8-M10.

Generic bolts for fastening all engine accessories.

Generic bolts, in regular production, they have the the most diverse shapes and 8.8 and 10.9 strength ratings, rarely 12.9.