Pre-Combustion Chambers

Pre-combustion Chambers
Pre-combustion Chambers

Masterparts offers a range of highly durable pre-combustion chambers.

What does a pre-combustion chamber do in a car?

Pre-combustion chambers are part of the indirect fuel injection system in diesel engines. They’re separate spaces designated to each cylinder inside the cylinder head.

In these types of engines, combustion begins in the pre-combustion chambers. The ignited air-fuel mixture then expands into the main combustion chamber.

Types of pre-combustion chambers

There are two types of pre-combustion chambers – active and passive.

Active pre-combustion chambers contain a fuel injector and a spark plug. Fuel is added to the chamber and then ignited. The resultant explosion ignites a lean air-fuel mixture in the cylinder, which would not normally ignite on its own.

Passive pre-combustion chambers only contain a spark plug. When the spark plug ignites, the flame spreads throughout the cylinder, creating a rapid combustion cycle.

How does a pre-combustion chamber work?

The pre-combustion chamber is connected to the cylinder by a series of small holes.

During the compression stroke, the piston moves up the cylinder, forcing air into the chamber. Fuel is simultaneously injected into the pre-combustion chamber, and combustion begins.

As the pressure increases, the leading edge of the explosion is forced through the holes. This splits the flame front into a number of smaller explosive jets, which ignite at multiple sites in the main combustion chamber.

For more about the different designs of pre-combustion chambers and how they work, try this video by Daily Motion.

Signs of a cracked or damaged pre-combustion chamber

Due to the extreme pressure caused by pre-ignition, pre-combustion chambers are prone to cracking. When the fractures are deep, the chamber may need to be replaced.

Stress relief cracks on a pre-combustion chamber

Stress relief cracks on a pre-combustion chamber. Source:

Grey or white smoke from the exhaust, or water leaking from the expansion tank, can be signs of a cracked pre-combustion chamber.

Unusual noises emanating from the engine, similar to the sound of stones rolling around in a tin can, can also indicate a problem.

A physical examination is required to properly assess the extent of the damage and associated risk to the engine.

High-quality automotive pre-combustion chambers for sale in South Africa

We offer door-to-door delivery. Alternatively, visit any of our branches in South Africa or in Windhoek, Namibia.

Pre-combustion chambers in and around Cape Town:

Pre-combustion chambers in KwaZulu-Natal:

Pre-combustion chambers in Namibia:

In addition to pre-combustion chambers, Masterparts stocks cylinder heads, cylinder head bolts, cylinder sleeves, cylinder knock sensors and other cylinder components – so you can complete a full engine repair with one stop. Contact us if there’s a part you need, and we’ll do our best to assist.


Call us on 021 657 5757 or complete the form below to get a quote.

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