Removing Diesel Adding Outboard

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   Thank you Charles.  Couple of things:  I think that the belt tension device is not necessary in the end, especially if using a full A-section belt.  Since the belt wraps all the way around the pulleys and does not go to a third idler pulley or anything, their is plenty of contact friction in those pulleys to drive the pump whose demand is 1/32 of a horsepower without much tention.  Also, there is not much room between the pump pulley and the sliding hatch on the port side, so it is important to keep the entire pump assembly as close to the engine as possible. Anyway, that is a minor detail.

One advantage of the recirculating cooling system is that it will allow us to experiment with hotter running thermostats without the danger of accumulating salt and mineral build-up in the block and head.  Raw water engine thermostats are set pretty cool to reduce that, and engines would prefer to be run hotter if they could.  That's next on my journey with this thing. 

I hope heads for this engine have not gone to $4,000.  I was able to salvage mine, but I think Keith Strutt from Crinmar indicated something in the $1800-$1900 range for a new head which is still not small.

Regarding the lack of oil filter, there is a little internal oil filter on (or in) the Bukh that upon cleaning I did see picked up some small bits.  However I have taken two of these engines apart and was amazed to see how clean everything was inside the crankcase.  Because the oil drain does not really come from the very bottom of the crankcase, and the method of pumping oil out via the dip stick tube from the top, I expected to see some sludge and some amount of "babbit" (small metal particles) accumulated in the bottom cover of the crankcase, but it was perfectly clean.  With relatively frequent oil changes, and periodically removing the little mesh oil filter and cleaning it, I did not get the idea that oil was a problem.  At 25 years old, there was no measurable ridge either at the top or bottom of the cylinder wall.  While I don't have a proper "inside" micrometer, I did use locking telescopic I.D. devices and then measured those with micrometer and would say that if there was measurable wear, it was in the .0005 range (1/2 of 1/1000th") which is nothing and indicates that things must have been pretty clean in there.

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frfletch Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 13 May 2008 Location: Canada Status: Offline Points: 365	Post Options Post Reply Quote frfletch Report Post Thanks(0) Quote Reply Posted: 11 October 2010 at 2:20pm
	Thank you Charles. Couple of things: I think that the belt tension device is not necessary in the end, especially if using a full A-section belt. Since the belt wraps all the way around the pulleys and does not go to a third idler pulley or anything, their is plenty of contact friction in those pulleys to drive the pump whose demand is 1/32 of a horsepower without much tention. Also, there is not much room between the pump pulley and the sliding hatch on the port side, so it is important to keep the entire pump assembly as close to the engine as possible. Anyway, that is a minor detail. One advantage of the recirculating cooling system is that it will allow us to experiment with hotter running thermostats without the danger of accumulating salt and mineral build-up in the block and head. Raw water engine thermostats are set pretty cool to reduce that, and engines would prefer to be run hotter if they could. That's next on my journey with this thing. I hope heads for this engine have not gone to $4,000. I was able to salvage mine, but I think Keith Strutt from Crinmar indicated something in the $1800-$1900 range for a new head which is still not small. Regarding the lack of oil filter, there is a little internal oil filter on (or in) the Bukh that upon cleaning I did see picked up some small bits. However I have taken two of these engines apart and was amazed to see how clean everything was inside the crankcase. Because the oil drain does not really come from the very bottom of the crankcase, and the method of pumping oil out via the dip stick tube from the top, I expected to see some sludge and some amount of "babbit" (small metal particles) accumulated in the bottom cover of the crankcase, but it was perfectly clean. With relatively frequent oil changes, and periodically removing the little mesh oil filter and cleaning it, I did not get the idea that oil was a problem. At 25 years old, there was no measurable ridge either at the top or bottom of the cylinder wall. While I don't have a proper "inside" micrometer, I did use locking telescopic I.D. devices and then measured those with micrometer and would say that if there was measurable wear, it was in the .0005 range (1/2 of 1/1000th") which is nothing and indicates that things must have been pretty clean in there.

WarBird Members Profile Send Private Message Find Members Posts Add to Buddy List Skipper Joined: 25 January 2006 Location: United States Status: Offline Points: 92	Post Options Post Reply Quote WarBird Report Post Thanks(0) Quote Reply Posted: 31 October 2010 at 7:29am
	Can the head gasket be replace while the motor is still in the boat. Rapscallion has a low C/R (very easy to crank ovr). We don't see water in the oil and all other indication are the otor is good, just no compression.

Guests Members Profile Send Private Message Find Members Posts Add to Buddy List Guest	Post Options Post Reply Quote Guests Thanks(0) Quote Reply Posted: 02 November 2010 at 5:28pm
	I have successfully removed the head and replaced the gasket a couple of times (before I removed the entire engine and went for an outboard). Its fairly easy - although I tell people its sort of like performing brain surgery thru the rectum. Ensure that you note which is the intake and exhaust valve rod for replacement. In order to hold the rods in their proper place when reattaching the head, I used small pieces of stiff foam which I tied to a string so that I could pull them out when the head was in-place. It was either that or stand the boat on its nose. This is also a good time to check the valve lash if you want.

frfletch Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 13 May 2008 Location: Canada Status: Offline Points: 365	Post Options Post Reply Quote frfletch Report Post Thanks(0) Quote Reply Posted: 02 November 2010 at 6:04pm
	I had the same thing happen recently, but unfortunately I had more to do than replace a head gasket. What had happened was: The head gasket became compromised when rust particles from the head broke loose and plugged the cooling water exit at the point where it joins the exhaust elbow causing over heating. After the event,the engine ran, but a small amount of moisture got into the cylinder via the head gasket. This froze the piston rings down into the grooves in which they are situated, preventing their outward spring action to engage the cylinder walls.....hence, no compression, and engine would no longer function. This required more work leading to my pulling the engine, going through everything, and while doing so I honed the cylinder walls and installed new rings. However, compression can also be compromised if the valves are not seating. This may require valve grinding, but first pull off the valve cover and check the clearance on the rocker arms to see if there is .20mm on the intake and .25mm on the exhaust side. If there is no clearance at all, then the valves will not come own and seat. I doubt this is your problem. Also check to torque on the injector hold-down bolts/nuts. Also, before starting anything, you should just check the tension on the head hold-down nuts which also hold the cylinder block in place. The workshop manual suggest these be checked periodically. When you go to remove the head in-situ, after the nuts are removed, do not go at the gap between the head and the cylinder block with a screw driver and hammer to pull them apart. You could try an aluminum wedge and hammer, but if none of that works, then: 1. Remove the injector nozzle. 2. Stick something down the hole to find the top of the piston and then rotate the flywheel until the piston is in the bottom position. 3. Fill the cylinder with gear oilvia the injector nozzle hole. 4. Replace the injector nozzle. 5. Loosen the hold-down bolts retaining the head a few turns. 6. Crank the engine over with the battery and key. This will pop the head off without you scaring the faces of the cylinder wall and the head on the first turn. 7. Clean up the spilt oil. To reduce mess, one may not have to fill the entire area with oil, but I have not tried it that way. The piston actually raises at the top just above the actual top of the cylinder, into the gap created by the head gasket, so there is not much volume when the piston is at the top. I should think that maybe only an inch of oil on top of the piston will do. Of course, if all the rings are siezed down, then this may not work, or will require more oil. I suggest using 90 weight gear oil for this to better your chances if any of the rings are compromised. If you don't have one, download a copy of the workshop manual for this engine before starting. It is much more comprehensive than the owner's manual. You can find it if you Google around a little. If you can't find it, contact me and I will send it to you in pdf. When the head has been pulled, you can also remove the cylinder block to see the condition of the rings. If they are all a mess, but no scoring or grooves are evident, you could just at that point remove the piston, clean the ring grooves, and replace the rings, however by this time a lot of work has been done and it may pay to remove the engine and go through it on the bench. I chose the latter as at 63, and with no discs remaining in any of my lumbar area and all lumbar vertebra degenerating, I have limited ability to work in those spaces for very long. If you elect to remove the engine, and if you have two windows in your cockpit (a Laser option, contact me for an easy procedure I've worked out to get the engine out without much effort or pain. Good luck.

Chris Ross Members Profile Send Private Message Find Members Posts Add to Buddy List Skipper Joined: 16 November 2005 Location: United States Status: Offline Points: 70	Post Options Post Reply Quote Chris Ross Report Post Thanks(0) Quote Reply Posted: 15 September 2011 at 7:19am
	How much is a rebuilt Bukh DV8 going for?

WarBird Members Profile Send Private Message Find Members Posts Add to Buddy List Skipper Joined: 25 January 2006 Location: United States Status: Offline Points: 92	Post Options Post Reply Quote WarBird Report Post Thanks(0) Quote Reply Posted: 04 October 2011 at 12:47pm
	Is the cylinder block seperate from the crankcase? Can I reassemble the pistonand rings into the liner with out removing the engine? Thanks.

Bill Layton Members Profile Send Private Message Find Members Posts Add to Buddy List Commodore Joined: 15 September 2002 Location: Canada Status: Offline Points: 551	Post Options Post Reply Quote Bill Layton Report Post Thanks(0) Quote Reply Posted: 04 October 2011 at 1:16pm
	yes you can but its gets complicated in that you need to find a way to support the crankcase while removing/installing the cylinder.... as the engine frame support attaches to the cylinder. Some people at this stage just yank the complete engine and do all the gaskets

WarBird Members Profile Send Private Message Find Members Posts Add to Buddy List Skipper Joined: 25 January 2006 Location: United States Status: Offline Points: 92	Post Options Post Reply Quote WarBird Report Post Thanks(0) Quote Reply Posted: 04 October 2011 at 2:23pm
	Thanks Bill