Heads and People

Yesterday afternoon I checked the seal of the four valves in the two heads by pouring solvent above the valves through the inlet and exhaust ports and seeing if any of the liquid got past the valves to the cylinder area below. Three of the four valves failed the leak test, even after I opened and flushed them out with solvent. Both of the valves in the #1 head, the one that had been recently machined, failed.

Stephen did some quick research and set me up with all of the information that I needed in order to do the valve lapping myself using grinding paste.

This morning I received an email from Colin to meet him at the boat ramp at 3 PM with one of my injector bolts and he would replace the two missing ones as well as the injector seal. He doubted that the injector bolt was made of stainless steel and he asked me to test one with a magnet and let him know the result as soon as possible. I don't have a magnet on board but soon figured out that the small compass at my navigation station would serve the purpose. Sure enough the bolt deflected the magnate indicating that it was not made of stainless steel.

I telephone Mark and he said that it would be a no. 8 grade nickel plated bolt, but he still needed to see the thread. I had sent him photos of my work with the #2 head the night before and he agreed to take the head and its injector out for checking and remedial work. I told him that I appreciated what he was doing and that I would pay him for his time and materials. He said that it was OK because he now had less of a work load and the doctors had sorted out his medication.

I ran into Bob at the marina and told him that Colin was back. "The good Colin or the bad one?" he asked. I told him that it was the good one.

Shortly after 3 PM Colin showed up and I told him about the valve leak failures, in particular the two valves of the #1 head whose valves had already been ground. Colin didn't question my finding and said that this has happened before. Before I knew it we were heading in his car across town to the shop where he gets the heads done.

A small hairline crack was noted in the #1 head and out came the fact that I had had the head skimmed. Colin never has diesel heads skimmed and told me that the important zone above the piston area had been OK. The outer areas had been rough but were not so important. Anyway, he figured that what was done was done and I had been doing my best. The hairline crack was maybe 10 mm long near the injector port. Colin had a good look at it and concluded that it must be some casting defect because he had never seen a crack in this area. No crack had been detected before the skimming and the head had never given a sign of this kind of failure so I tended to agree. Besides, I told him, I had no choice in the matter. I was not going to order another new head. I picked up one of the valves and asked if any of them were bent or warped. Colin replied that they were OK and they did look OK to me. So we left the heads for a valve grinding and Bob will pick them up tomorrow. He will take the injector to another place. I asked him to email me when all was ready.

During our drive we discussed my engine. He is now pretty convinced that the antisiphon valve failed and water backed into the cylinder heads, causing the #1 cylinder to crack. I never saw evidence of this when I removed the mixer and hosing, but it is conceivable that I had started the engine which forced the water out cracking the head along the way. I told him that I am accustomed to seeing steam in the engine exhaust and in his opinion steam should never come out of the exhaust, and its presence indicates insufficient cooling water.

... But wait a minute, a week or so ago I was given the idea that the engine was running too cool and I should use the water inlet thru hull valve to choke back the sea water supply to the engine. I really get confused at times.

He told me some horror war stories of cooling system failures. One guy raised his water line 2 inches and painted across two openings on each side of his hull. What he didn't notice was that between each pair of these openings were tiny holes which were somehow related to the antisiphon system, and he had blocked them up with paint. Both of his engines got flooded with water. Colin managed to save them, saving the owner a $35k repower bill. Apparently a lot of engines are ruined by this kind of flooding.

So tomorrow I will have a good look at the antisiphon setup and make sure that there is no blockage. I'll revisit the water pump and make sure that the check valve is functioning OK.

When I get the heads and injector back I'll reassemble the engine and try to start it. It will either run or not run. My guess is that it will run, although perhaps not very well. I'm also guessing that it will be extremely unreliable and should be nursed through the final weeks of its life.