Lower face of 2YWM Head showing valves and cooling ports
2YWM cylinder head
After 20 years in the boat, and just over 3,000 hours running, I decided that it was time that Albert’s engine had a professional decoke. I have decoked the exhaust manifold and the exit to the ports on a couple of occasions and each time has brought an improvement in performance. However, I was concerned about areas of the cylinder heads I couldn't reach because over the years the engine has become “less bright” when close to tick-over. I therefore decided that it was time to entrust the engine to Phil Lizius of Longboat Engineering at Blisworth who has all the necessary experience and spares to carry out rebuilds.
We decided that moving the boat to Sandling Wharf on Blisworth Arm where Phil lives and works would be the best approach, so we moved the boat on February 6th. It turned out to be the last day we had half-decent weather. Geoff & Shirley Emmins volunteered to help us up Stoke Bruerne Locks. Geoff, being a civil engineer wanted a trip through Blisworth Tunnel. The weather was fine as we left Yardley Gobion but as we got to the top lock at Stoke the rain started (and it then continued for several days). We were almost the only boat moving and the trip through the tunnel was very easy but very wet. The roof of the "wet end" of the tunnel (northern) was really flowing and we couldn't avoid going through some of the substantial waterfalls.
Phil took off the heads last week. He initially discovered very little by the way of carbon deposits, but when fully stripping the heads he found a sizable deposit just behind one of the exhaust valves in a location inaccessible via the exhaust ports. This is encouraging since it might indicate a reason for a performance drop-off. We are now waiting for the valves to be machine lapped before the heads are reassembled.
The impressive thing about the heads, to me, is there size and weight. Being brought up repairing 1930s Austin Seven heads in the mid 1960s these are quite different. No thought of weight saving – they are built for endurance.
We now have a short delay because the winds have brought power cuts to the area and the machining is delayed until the power goes back on! :Luckily our home has not been affected.