I'm starting this tread to provide a central place for information about Bukh
DV20 and DV10 diesel
My 10m Cavalier 32 yacht has a DV20 and I've spend many hours on maintenance
issues, one of which is the raw water cooling
Yes, the Bukh
is very old-fashioned; compared to modern high speed engines its heavy and not super fuel
efficient. However it is a simple and reliable piece of kit designed originally for lifeboat propulsion
, can be hand started, has no expensive ECU electronics
to burn out, and once started will run with no electrical
input (unlike most modern diesels which require constant electrical
input). With proper maintenance
by the owner, these engines will go for 10's of thousands of hours.
To start this thread off I'll mention a recent experience of a friend who had his DV20's high pressure fuel pump
professionally rebuilt. Before my friend installed it back on the engine
, he asked the pump
rebuilder about injection timing (the pump
is timed by adding or subtracting thin brass shims between the pump body and the engine
block). The rebuilder advised him to either 1) reinstall the pump with the original number of shims or 2) follow the official timing procedure described in the engine workshop manual. The choice was his.
My friend opted to use #1, the easy method. The engine started, but within 10 seconds was shaking violently and the very heavy flywheel sheared off all its 6 hardened steel
bolts, dropped off the end of the crankshaft and did quite a lot of damage to the engine space before it finally stopped moving. He's now having to figure out a way to get the sheared off bolts out the crankshaft without destroying the female threads, not a happy camper!
During performing the proper workshop timing procedure, it was discovered that injection was happening AFTER, not before, top dead centre which was the cause of the large vibration.
The Bukh DV20, unlike most 2 cylinder engines, have both pistons raising and falling together, and to balance the rotational mass of the crankshaft and pistons, they have a separate geared a counter-weight system. The stresses imposed by fuel
burning at the wrong time could not be smoothed out by this system and the violent pulses sheared the crankshaft bolts (that heavy flywheel has a lot of inertia!).
Moral of this story is: if you remove the high pressure pump, perform the proper workshop method for re-timing!
I and other Bukh owners would appreciate any tips, experiences, questions you might have for this thread.
Nuku in New Zealand