Bukh replacement

[neil_s]

Well, the DV 20 in my Seal 28 is original from 1977 and despite it's long term low oil pressure is still a good goer. The 5 psi is always on my mind, though, and every now and then, I have a little panic. I spotted a DV 24 for sale - same basic engine and a direct plug-in for my DV 20 - or so I thought. My DV 20, however, has the older BW 6 gearbox and the DV 24 has the BW 7. These two gearboxes are completely different designs, The BW 7 is shorter, and has a higher level output shaft. The problem! I would have to reduce the height of my engine bearers to get the engine to line up with the prop shaft. Unfortunately, the after end of the bearers is already touching the inside of the hull. It occurred to me, though, that maybe I could fit the BW 6 gearbox from my old motor to the new one and get back to a direct plug in replacement. I think the mounting flanges are the same, but have no idea about the shaft coupling inside. The DV 24 generates it's 24 hp at 3600 rpm but I would restrict it to 3000 rpm - max rotational speed of the DV 20 - where it gives a very similar 22 hp. Any Bukh experts out there with thoughts of feasibility of this swap?

 

[Boater Sam]

Possible the same number of splines etc., but its only a case of the correct drive plate surely?

 

[neil_s]

Possible the same number of splines etc., but its only a case of the correct drive plate surely?

I am worried by the crankshaft nose. The old DV 20 has a taper with keyway and a clamp nut. I can't find details of the newer engines, though. If it's the same, then you're correct - the old gearbox and drive assembly would just swap over.

 

[LittleSister]

I spotted a DV 24 for sale - same basic engine and a direct plug-in for my DV 20 - or so I thought.

The DV24 (and related DV36 3 cylinder) is actually a somewhat different engine from the DV20 (and related DV10 single cylinder), though they share quite a few parts, and I've read the 'footprint' is the same making it easy to use as a replacement for the DV20 in terms of mounting.

I don't know about the of the compatibility of the DV20 engine and BW7 gearbox shafts' couplings.

There's an active Bukh Marine Diesel Owners Group on Facebook, with both owners/users and vendors of s/h parts and engines regularly posting, and I dare say someone on there would be able to advise. I am sure someone on there would have faced the exact same challenge as you at some point.