Head Handover

I met Colin at the boat ramp at 8 AM and handed over the "spare" head. It had been stowed low under the starboard quarter berth because of its weight but it looked like I had wrapped it in plastic well enough to protect it from bilge water when the boat rolled to starboard.

The first thing that Colin did was to show me the cracked head, and we're not talking about a hairline crack - it was wide and easily visible. The valve stems are about 25 mm apart. The crack ran across that section, including the liners of the valve stem openings. He will give me the head when he has finished with it so that I can photograph the crack for the blog.

The head didn't just crack on its own. Colin says that water must have gotten into the cylinder. Because water does not compress the forces inside that cylinder during compression were too great and something had to give. Sometimes the piston rod bends and sometimes the piston cracks. In this case the head cracked which Colin says was very fortunate.

He thinks that it is unlikely that there is damage in the piston area, but he wants me to inspect the cylinder lining and to measure the piston clearance at TDC by putting a straight edge across the bore and measuring the gap with a feeler gauge. He will compare this with the specifications in my SABB manual, which he has in his possession. The size of this gap will indicate to him whether or not the rod has been bent.

He inspected the "spare" cylinder and was very happy with what he saw. He says that he will treat it with acid to clean it up then inspect it for hairline cracks using acid again, if I got that right. He also talked about polishing the surface.

There has been one slight delay. Colin went to the only work shop that he trusts and uses and they are closed until next Monday, probably due to the Easter season. He asked how much time I had and I told him that I had been hoping to sail out on about 1 May but I would stay as long as I had to, though my big concern was to leave the area before the advent of the hurricane season. He replied that there was no problem, and that he hoped to have me up and running by the end of next week.

We agreed that it was very fortunate that the head had been replaced with a new one in Port Townsend, because it provided me with the spare that I was prudent enough to bring with me. Colin was amazed that the head had been swapped rather than reworked. Here in Mexico they have more of a tendency to fix up and refurbish. In this case it worked to my advantage.

Along those lines, Colin says that they can actually replace the tips on injectors. This came out of a question that I posed on whether it would be a good idea for me to carry a spare injector. He said no, because they rarely fail. (I hope I don't come to rue that advice.)

In Port Townsend we had ordered one new head from SABB and received two. I had been kicking myself for sending the extra one back to Norway instead of having it mounted on the engine or at least carried it as a spare. But who knows, it could have been a new $900 head that cracked instead of the old one, which would have annoyed me big time. This raises a fundamental question of what caused the ingestion of water into that cylinder. Colin is aware of that issue and will focus on that when he puts the engine back together.

Colin, by the way, set up the Moorings maintenance operation here and over the course of 8 years wound up maintaining their 15 boats.

Anyway, I am feeling cautious optimism, as they say. Time will tell whether this roller coaster keeps going up or takes a sudden downward plunge.