Can you Fit a Catch Can to a Petrol Vehicle?

Contrary to popular belief, catch cans aren’t just for diesel engines. Whilst crankcase gunk build-up isn’t as of an issue for petrol engines the way it is for their diesel counterparts, petrol engines also benefit from preventing crankcase emissions from entering the engine’s air intake. 

Fitting a catch-can to your engine helps protect against a little thing called “blow-by”. During the engine’s operation, a small amount of combustion gas sneaks its way past the piston rings and into the crankcase. These combustion gases mix with the oil vapour in the crankcase, creating an oil mist that makes its way through the engine’s PCV system and back into the intake. This cocktail of air, fuel, and oil is what we call blow-by. 

When drawn into the engine’s combustion chamber, blow-by can reduce the effective octane of the fuel-air mixture and cause detonation. The oil mist created from blow-by can also coat important air intake components such as an intercooler, reducing efficiency. As oil enters the intake, it also has a habit of sticking to the back of the engine’s intake valves, creating carbon-build up, which can further hurt efficiency. This is especially common on direct-injection engines where there is no injector spraying fuel on the intake valve.  

Engines that use forms of forced induction, such as turbocharging and supercharging, are prone to creating more blow-by due to the added combustion pressure.  

A catch-can fits up to a petrol engine the same way it would to a diesel engine, sitting between the engine’s PCV system and air intake system. The catch-can’s job is to catch the blow-by particles before they reach the intake, keeping your engine clear of blow-by contaminants and protecting it from potential damage.  

All engines produce blow-by, even in small amounts, so it doesn’t hurt to fit one up for the sake of preventative maintenance. Fitting a catch-can can also help you monitor the condition of your engine by allowing you to monitor the amount of blow-by your engine is producing.  

The Ryco RCC351 Catch Can is designed to filter out blow-by and recirculate cleaned air back into the intake. The impurities are trapped in the particulate filter and drip down to the high-capacity 310ml reservoir. The reservoir has an 8mm quick-drain fitting so that oil can be easily disposed of. The Ryco RCC351 Catch Can also comes with an internal relief valve that acts as a by-pass valve to regulate pressure for engine safety. One closes to prevent air rushing back into the crankcase under engine overrun conditions.

The other prevents oil from going back into the engine sump or intake manifold when the reservoir fills up with oil. For easy mounting in the engine bay, the RCC351 comes with a quick connect bracket for easy install and removal for servicing. The Ryco RCC351 Catch Can is suitable for engines up to 350kW, producing up to 200 lpm of blow-by gas flow.