Pistons

Are you rebuilding your engine after wear, or does it need to handle more boost in a turbo project? We have pistons in standard and oversize, forged or cast, for both car and motorcycle engines, so you can match bore and compression to your specific engine.

Forged or cast pistons

The type of piston should depend on what the engine will be used for. Forged pistons are typically stronger and handle higher boost, high revs and track days better, but they often expand more when hot and therefore typically require greater clearance to the cylinder wall. Cast pistons can be a sensible choice for an engine built close to stock.

How to choose the right piston

• Engine code: The piston must fit the specific engine, e.g. Honda D16Z6, Nissan SR20DE or Mitsubishi 4G63T, which several pistons from CP Pistons are made for.
• Bore and oversize: Choose STD or e.g. +0.5 mm and +1.0 mm based on the cylinder dimensions after machining.
• Compression ratio: Turbo engines often use lower compression, e.g. 8.5:1, than naturally aspirated engines. The shape of the piston crown and its volume in cc affect the compression.

Brands in this category include Wiseco, JE Pistons, CP Pistons, Mahle and S&S Cycle.

Rings, wrist pins and installation

Many pistons are sold individually, and some come with rings. Check the product description, or otherwise find piston rings, wrist pins or a complete piston set. During installation, clearance and ring gap should be measured according to the manufacturer's instructions, as incorrect measurements can cause wear, loss of compression or engine damage.

Frequently asked questions

Why are many pistons sold individually?

Many pistons, e.g. several from CP Pistons, are sold as a single piston, so you can replace one damaged piston or put together exactly the number your engine requires. If all cylinders need new ones, a piston set may be more practical.

How do I find the right oversize?

It depends on the cylinder dimensions after boring or honing. Have an engine shop measure the bore and choose the piston accordingly. The manufacturer's recommended clearance determines the final size the cylinder must be machined to.

Can I use pistons for a naturally aspirated engine in a turbo engine?

This is typically not recommended. Pistons for turbo engines often have a lower compression ratio and a dish in the piston crown. A high compression ratio combined with boost can increase the risk of knock and overheating.