So, I disassembled the top of my Yanmar SB8 engine...
...isn't that how all bad stories start??? The head came off grudgingly but off it came. Turns out that the valves were fine but the water passages were mostly stopped-up. I also learned the value of a powerful magnet on an extension: 1) When you are not paying attention and you drop a pushrod down into the engine case, a magnet on a long extension handle is your best friend... 2) Also when cleaning rust out of water passages it turns out that (thank goodness) rust is actually STILL magnetic! My water passages never looked so good. I couldn't vacuum-out the rust or turn the engine upside down, so the magnet was a real life saver.
The next step is to bring the head to the engine shop to get professionally degreased and then decked/faced to ensure that it is truly flat. Being an old hand with performance cars part of me can't resist perhaps getting a multi-angle valve grind and then maybe port and polish the intake/exhaust passages.... Being just an 8hp, single cylinder diesel that would just be sure madness, but there just might be an extra 1/2 horsepower lurking in there somewhere (right next to the roller-bearing rocker arms, right?)...
I have the new head gasket all ready to go. My only concern is the high-pressure injection pump. I'm not sure it is working and I'm not sure if it can be rebuilt or just purchased new?
...isn't that how all bad stories start??? The head came off grudgingly but off it came. Turns out that the valves were fine but the water passages were mostly stopped-up. I also learned the value of a powerful magnet on an extension: 1) When you are not paying attention and you drop a pushrod down into the engine case, a magnet on a long extension handle is your best friend... 2) Also when cleaning rust out of water passages it turns out that (thank goodness) rust is actually STILL magnetic! My water passages never looked so good. I couldn't vacuum-out the rust or turn the engine upside down, so the magnet was a real life saver.
The next step is to bring the head to the engine shop to get professionally degreased and then decked/faced to ensure that it is truly flat. Being an old hand with performance cars part of me can't resist perhaps getting a multi-angle valve grind and then maybe port and polish the intake/exhaust passages.... Being just an 8hp, single cylinder diesel that would just be sure madness, but there just might be an extra 1/2 horsepower lurking in there somewhere (right next to the roller-bearing rocker arms, right?)...
I have the new head gasket all ready to go. My only concern is the high-pressure injection pump. I'm not sure it is working and I'm not sure if it can be rebuilt or just purchased new?
