Engines & Components

Is your engine stripped down on the bench, or do you just need new valve springs for the cylinder head? In this category we bring together engine parts for projects that demand more than the original parts can handle: pistons, connecting rods, crankshafts, camshafts, bearings, oiling systems and cylinder heads. The parts are aimed at you if you are building for higher boost, more revs or track use.

What the parts in the engine do

An engine consists of systems that have to work together. The rotating assembly – crankshaft, connecting rods and pistons – converts combustion pressure into torque, while the camshaft and valvetrain control when air flows in and out. Bearings and the oiling system keep the moving parts separated by an oil film, and the cylinder head has a major influence on how well the engine breathes. If you increase boost or revs, the load on every part rises, and the weakest link sets the limit. So plan the whole project before you buy individual parts, or take a look at a complete engine kit with rotating assembly.

How to choose pistons and connecting rods

The pistons must match the bore, stroke, rod length and the compression ratio you want. For high-boost engines, lower compression is typically chosen, often via a dish in the piston crown. Also look at the ring pack, wrist pin and any coating. The range includes, for example, Wiseco piston kits and ring sets as well as Manley piston kits for the Chrysler 6.4L Hemi, and JE Pistons and Eagle are also among the brands. The connecting rods must be able to withstand the increased load and have a length that suits the piston and crankshaft – especially in stroker projects where the stroke is changed.

Camshaft and valvetrain must match

A camshaft with more lift and longer duration can move the power band upwards, but the valve springs, retainers and valve locks must be able to keep up. Too little spring pressure can cause valve float at high revs, while unnecessarily high pressure can increase wear on the cam and lifters. So choose based on lift, spring pressure, piston-to-valve clearance and how the engine is used. COMP Cams, for example, offers a beehive spring kit with steel retainers for the Dodge 5.7L Hemi model years 03-08, designed for 0.600 inch lift.

Installation, tolerances and break-in

High-performance engine parts require precise installation. Bearing clearance, piston clearance and ring gap must be measured and adjusted according to the manufacturer's instructions, and the ring gap depends on factors such as bore and application. Check that the parts fit your specific engine and build, including bore, compression height and bearing dimensions. An upgraded oiling system can be relevant at high revs or for track use, where oil pressure can drop in hard corners. After assembly, the engine is typically broken in according to the manufacturer's instructions, and the first oil change is done early to remove wear particles.

Frequently asked questions

Do I need to change pistons if I increase boost?

It depends on the engine, the original pistons and how much the boost is increased. For bigger changes, lower-compression pistons are typically chosen, but the choice should be assessed together with connecting rods, fuel and engine management.

Should the camshaft and valve springs be replaced at the same time?

Often, yes. A camshaft with more lift or a more aggressive profile may require different springs, retainers and valve locks. Check the cam manufacturer's recommended spring pressure and the piston-to-valve clearance before you assemble the engine.

Can I assemble the engine myself with the new parts?

It requires experience, precise measuring tools and the manufacturer's specifications. Bearing clearance, ring gap and torque specs must be checked carefully. If you don't have the equipment, the safest option is to let an engine shop handle the assembly.