Fuel problem

[RichardS]

When you took the head off and inspected the gasket, the valves and seats, was there any obvious issue which would cause loss of compression? If not, can you see any movement in the piston as it moves up and down the cylinder or any obvious pitting or scoring in the bore?

If it all looks good, use some thin oil in the bore to see if it drains down past the rings. If the oil vanishes within a few seconds then you probably need a rebore and new pistons. You can use diesel for this test but you will need to change the oil before running the engine.

You definitely need to identify the source of the compression loss before you reassemble the engine.

Richard

 

[Thedigger]

If you have the head off, reseat the valves using Valve grinding paste and a suction cup stick.
Google how to grind in valves if you don't know how.
If the valve is causing the lack of compression, that should sort it out. A wire brush on an electric drill will help clean out the chambers.

Okay you saying drill out the carbon or use drill to clean out water chambers ?

 

[Thedigger]

When you took the head off and inspected the gasket, the valves and seats, was there any obvious issue which would cause loss of compression? If not, can you see any movement in the piston as it moves up and down the cylinder or any obvious pitting or scoring in the bore?

If it all looks good, use some thin oil in the bore to see if it drains down past the rings. If the oil vanishes within a few seconds then you probably need a rebore and new pistons. You can use diesel for this test but you will need to change the oil before running the engine.

You definitely need to identify the source of the compression loss before you reassemble the engine.

Richard

 

[Thedigger]

Can't see anything that stands out as a combustion issue but I'm not expert

 

[Caraway]

I’m wondering if the fuel is blocked at the jet point just before it enters the cylinder. If no fuel is getting through then that would cause low compression? I can see fuel at the injection pump and there was signs of air so primed that out. Is it possible the fuel is blocked at the atomiser? So no fuel entering the chamber would result in low compression?

I suggest you sell the boat.

 

[179580]

You need to do as previously advised, piston half way down, pour just enough diesel in the pot to about 1mm over the top of piston. If it immediately disappears then you have a ring problem. Secondly you need to strip the valves out and inspect the seats and faces. Get them recut if necessary.

 

[RichardS]

Can't see anything that stands out as a combustion issue but I'm not expert

You need to turn the engine with spanner or just turn one of the pulleys by hand and move the piston down to the bottom to check the bores.

I also can't evidence that the valves were stuck or burned out. There might be a lot of carbon deposit on the head outside of the head gasket or it could just be dirt from another source. Check the metal lip around the bore on both sides of the gasket and see if there is any sign of combustion gases passing across that metal lip.

Are you sure that it wasn't just a jammed compression lifter which was holding the valve open?

Richard

 

[179580]

On closer examination of the cylinder head shot. Is that corrosion into the jacket bottom right? Also, the sealing witness looks as it has been compromised at about 1100 to 1300. Would be better if you cleaned it and posted another shot.

 

[Thedigger]

If you have the head off, reseat the valves using Valve grinding paste and a suction cup stick.
Google how to grind in valves if you don't know how.
If the valve is causing the lack of compression, that should sort it out. A wire brush on an electric drill will help clean out the chambers.

I've managed to get an engineer to look at the cylinder head and the valves and will give them a clean up.

 

[Thedigger]

You need to turn the engine with spanner or just turn one of the pulleys by hand and move the piston down to the bottom to check the bores.

I also can't evidence that the valves were stuck or burned out. There might be a lot of carbon deposit on the head outside of the head gasket or it could just be dirt from another source. Check the metal lip around the bore on both sides of the gasket and see if there is any sign of combustion gases passing across that metal lip.

Are you sure that it wasn't just a jammed compression lifter which was holding the valve open?

Richard

I'm handing over the head to an engineer next week so he can give it a survey