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Why Exhaust Valves Are More Likely to Fail in Bi-Fuel Cars

Model: (Various brands) Various
Part: Engine

Video tutorial

This video explains why LPG and methane engines are more likely to have damaged exhaust valves. In the cylinder head, the smaller valves are the exhaust valves, while the larger ones are the intake valves, which ensure a tight seal during compression and combustion phases.

But why do exhaust valves fail in bi-fuel engines? The intake valves come into contact with fresh air, while the exhaust valves, when opened, encounter very hot air due to the end of the combustion process. In these types of engines, combustion occurs at significantly higher temperatures, and the combustion duration is longer compared to petrol cars.

Therefore, the exhaust valve will also impact combustion residues, which can easily damage it, failing to maintain cylinder sealing and causing gas leaks from the valves. This can be remedied by sintering the valve seats, a typical characteristic of bi-fuel engines.


Updated on 22 September 2026 by ScegliAuto


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