Bukh Oil Consumption

[Guest]

Oil consumption previously minimal but last two years approx 0.1litre per hour consumed when under 2/3 load or above. Minimal oil consumption if under 1/2 throtle (revs not certain). A puff of blue smoke evident when increasing revs. Difficult to detect during running due to white smoke - always been present - previous post on this noted. Thermostat opens at 60*C. No obstructions in suction or feed pipes. Engine temperature feels correct. Engine starts readily. No evidence of oil leakage. No oil in cooling water. No water in oil. Volvo Penta 15/40 oil used. Bukh DV20 circa 1983. Otherwise seems OK. Any thoughts?

 

[vyv_cox]

Bore wear almost certainly. How is starting in cold weather? This is likely to be the next problem. Do you have/need the optional glow plugs?

New rings might help but not in the long term. A rebore and pistons will eventually be the only option, but it would not be worth doing this alone, so new bearings at least, and probably a re-ground crank, will be required. The cost is horrendous, a gasket set is something over 200 pounds! Start saving up, or sell the boat.

 

[BOBBIN]

Try cleaning the vacume valve in the rocker Box.

 

[Footpad]

Didn't know they did glow plugs? When our engine became hard to start in very cold weather we were offered an air intake heater option, it certainly did the trick.

 

[vyv_cox]

You're probably correct, I read "cold starting device" and thought I remembered reading of a glow plug add-on but maybe it was another engine.

The crankcase breather vacuum valve is a possibility, and a lot cheaper than an engine rebuild! My experience is that the engine smokes all through the rev range when this needs cleaning. Plus it's the smoke that makes it clog up, so the implication is that the engine is already well worn anyway.

 

[Guest]

Thanks - I will physically check the vacuum valve. I had tested this by checking if a sheet of paper is held over the oil fill hole rather than being blown off.
I'll also start saving!