Fitting a new cylinder head and rebuilding

In part 1 of this article we followed Geoff Higginbottom as he dismantled his Bavaria 39’s 2005 Volvo Penta MD2030 diesel engine to diagnose the reason for its power failure and excessively smoky exhaust.

Geoff discovered a failure in the pre-combustion chamber in the aft-most cylinder, which led him to spend £1,200 on a brand new Perkins head (although Volvo insists its heads are machined differently to Perkins’ the fact remains the engine started out life as a Perkins). The Volvo version would have cost 20% more; only time will tell whether that would have been money well spent…

Geoff also took the opportunity to do a full engine service, changing all fluids, replacing perishable gaskets, seals and installing a new thermostat. As part of that service he sent his three injectors off to be reconditioned for an excellent price.

What we might never find out is what caused the engine failure in the first place. PBO engine expert Stu Davies suggests: “The MD2030 has a bit of a reputation of the No3 cylinder having problems. It is the one nearest the exhaust raw water injection point and if any blockage of the exhaust or failure of the anti-siphon valve occurs sea water gets back to that cylinder and starts to cause problems like Geoff has suffered. I’d suggest that he checks his anti-siphon valve to make sure it hasn’t stuck!”

Geoff confirms: “I believe my anti-siphon is currently operating correctly but will obviously make it a priority to check when I get back on board. I’d noticed when I bought her there were signs of discharge from the leak-off pipe, which I understand is a symptom of a dodgy valve, but these appeared to be old. I have in fact been running with the pipe detoured into a container so I could monitor for discharge, but there has been none. However I was totally unaware of the importance of this valve and the potential impact.”

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