Engine Internals

Engine internals are the parts inside the block and head that turn combustion into rotation and keep the engine sealed. They include pistons, connecting rods, bearings, valves, springs, camshafts, gaskets, and the studs and bolts that hold it all together. They are usually changed as part of a rebuild, often to prepare an engine for boost, higher revs or long track sessions.

The section is split by job:

• Pistons & Rods: forged pistons, ring sets, gudgeon pins and connecting rods.
• Gaskets & Seals: head gaskets and complete gasket sets.
• Valvetrain: valves, springs and retainers.
• Engine Bearings: main and rod shells.
• Cams & Sprockets and Oil Management: the timing and lubrication side.
• ARP: head studs, main studs, rod bolts and fasteners for the rest of the engine.

Listings give the details an engine builder needs, such as bore and oversize, compression ratio, material and gasket thickness.

An engine build is a system, so plan it as one. Decide the target first (boost, revs, fuel), then choose pistons, rods, gasket and fasteners that suit it together. Book the machine work as well: boring and honing, decking, and balancing the rotating assembly. Measure rather than assume, from bearing and piston clearances to ring gaps and the head gasket’s effect on compression. Parts designed to be used once, such as stretch bolts, bearings and gaskets, should be new, and the engine calibration must be updated for the new specification.