View Full Version : Bukh DV20 valve clearance?

11-09-2015, 10:43 PM
Hi all

I am the usually-proud owner of a CO32 with the original Bukh (http://www.cruisersforum.com/forums/tags/bukh.html) DV20 still running. Maybe I should feel lucky that it still runs at all... but I notice some deterioration over the last cruising season so I'm starting to investigate.

I've been tinkering cautiously with the engine (http://www.cruisersforum.com/forums/tags/engine.html), trying to find out why one cylinder starts far more willingly than the other (which joins in 30 or more seconds later). One thing I checked right away was the valve adjustment.

The Workshop Manual calls for .01 inch for the inlet and .012 for the exhaust (http://www.cruisersforum.com/forums/tags/exhaust.html) valves. When I checked them, the clearance was about twice that -- .02 at least, all round.

I thought "Aha, smoking gun!" and corrected the clearances; after reassembly, started the engine (http://www.cruisersforum.com/forums/tags/engine.html). It still started hard, with one cylinder leading by half a minute or more. Worse than that, it was now tremendously noisy with major valve clatter. I killed it quick and sat down to think.

The manual is unambiguous. There is no room for misunderstanding. It says .01 inch and .012 inch. And yet my valve clearances were double that. And yet it's noisier with the clearances corrected.

I am not expert in diesel (http://www.cruisersforum.com/forums/tags/diesel.html) engines -- can you tell? Can anyone tell me whether there is any *reason* why a previous owner or mechanic (http://www.cruisersforum.com/forums/tags/mechanic.html) would have deliberately defied the manual and set such a generous clearance? is there a reason why the correct setting should be noisier than an apparently wrong setting?

To those who say "oh chuck the thing and repower (http://www.cruisersforum.com/forums/tags/repower.html) already," believe me I have been considering that option, but it's awfully expensive :-) for the moment, I'm exploring the "keep it running a few more years" option.

thanks in advance for any light you can shed