BUKH ENGINE, HOW DOES THIS WORK?

[Guest]

Quote from TW Marine website:

"The two and three cylinder engines meet the requirements of IMO resolution A521part of which specifies that the engine should be able to run upside down for a minimum of ten seconds and run submerged in water up to the middle of the crank. The demand for this last test is five minutes, but after one hour, the Bukh engine was still running steadily !"

 

Howdoes this work, is it a dry sump engine perhaps?

I just wondered, because I rolled a car once and the engine seized after about ten milliseconds when upside down. Ten seconds seems an amazing time for an engine to run when starved of oil.

[Hairy-Neil]

At the annual Austin A35 Club gathering a couple of years back, one of the entertainment events involved draining the oil and water from a scrap Maestro Diesel and driving it round the arena till it self destructed. It lasted a surprisingly long time, around 15 - 20 minutes if I recall correctly....

[Guest]

At the annual Austin A35 Club gathering a couple of years back, one of the entertainment events involved draining the oil and water from a scrap Maestro Diesel and driving it round the arena till it self destructed. It lasted a surprisingly long time, around 15 - 20 minutes if I recall correctly....

That is amazing. I always believed that big end bearings gave up the ghost very quickly without oil pressure. They did in my VW definitely. I remember the Slick 50 advert though where a car was treated and then driven without oil (allegedly) for some time. In another way though, the Maestro thing doesn't surprise me. We had diesel Maestro vans at one company which were thrashed unmercifully for some years by several drivers, and the engines seemed fine. They were falling apart, but ran very well.

[Maverick]

That is amazing. I always believed that big end bearings gave up the ghost very quickly without oil pressure. They did in my VW definitely. I remember the Slick 50 advert though where a car was treated and then driven without oil (allegedly) for some time. In another way though, the Maestro thing doesn't surprise me. We had diesel Maestro vans at one company which were thrashed unmercifully for some years by several drivers, and the engines seemed fine. They were falling apart, but ran very well.

 

Remember fitting a big end shell the wrong way on a mk 1 escort once. without the drainhole lined up to drip the oil to the crank shaft the bearing went within seconds

[RLWP]

the engine should be able to run upside down for a minimum of ten seconds

 

Notice however that it doesn't say "run upside down for a minimum of ten seconds without any damage to the bearings whatsoever, and be able to do this over and over again". As long as it survives once and can then run on long enough to get a ship to safety, that's all that would be required.

 

Think of like a seatbelt. If a seatbelt works once in an accident, then that's what it is supposed to do. No manufacturer would then guarantee that could do that job again.

 

Still, makes you think though....

 

Richard

[John Orentas]

I am not sure this is so surprising, presumably the engine is not under much load and the oil is still in there, virtually atomised and splashing around, though I must say that I have never heard of this upside down test before but many engines have massive reserve of oil my engine my engine requires one gallon of oil to reach the normal level on the dip-stick but it will take another gallon to reach the 'high' level.

 

The semi submerged test is quite standard, you will notice that on true marine engines all electrics and other sensitive bits including starter motors, alternators, breathers etc. are always mounted high on the cylinder block. Most too have single side servicing, all serviceable parts are on one side of the engine which can be installed hard up to a bulkhead.