I initially expected this to be straight forward, but hit a snag pretty quickly. The head was already removed from the barrel, so the tappet covers, cam cover and cam removal were all simple.
The issue was with removing the tappets. The service manual suggests using an M6 thread screwed into the tappet pin and using a slide hammer to extract. Unfortunately M6 is not the correct size. The thread is M8, but from the little information on the forum, it appears that many pins have faulty threads. One of my threads was fine. On the intake side the bolt (M8x100mm bolts. Not having a slide hammer, I also bought some nuts and mudflap washers) threaded straight in and using both my framing and dead blow hammer, taped it out with little effort.
The exhaust side was the problem. The thread was not clean and I was concerned about cross threading the tappet pin. As a result, I bought a metric tap and die set (handy anyway as I have a heap of threads with mild corrosion to clean up).
A quick clean up with an M8 x 1.25 tap and the bolt went in fine. The problem was the pin was quite hard to remove. Instead of using brute force, I elected to extract using the nut and washer working against the face of the hole. Once fully against the washer, the pin tapped out as per the other side. I couldn''t see any reason for the difficulty, so I am curious as to whether the exhaust side is hotter and/or dirtier. This pin actually smelt different, much like a diesel locomotive.
I also noticed some damage to this area. The bottom of the mounting face has a big dent on it, in fact it has deformed all the way through to the inside, and had caused the mounting face to rise. Above is after a couple of minutes of light file action to remove this. The slight deformation does encroach the gap around the oil gallery bolt, but not greatly.
I have checked the deck level (really good) and the valves seal I tested with fluid (in my case not water, but pouring degreasing fluid back through the inlet and exhaust ports) and did not leak. Despite the slight damage to one cooling fin, this appears to be a good head. Just need to remove the vales and check the valves and spring tolerances.
The issue was with removing the tappets. The service manual suggests using an M6 thread screwed into the tappet pin and using a slide hammer to extract. Unfortunately M6 is not the correct size. The thread is M8, but from the little information on the forum, it appears that many pins have faulty threads. One of my threads was fine. On the intake side the bolt (M8x100mm bolts. Not having a slide hammer, I also bought some nuts and mudflap washers) threaded straight in and using both my framing and dead blow hammer, taped it out with little effort.
The exhaust side was the problem. The thread was not clean and I was concerned about cross threading the tappet pin. As a result, I bought a metric tap and die set (handy anyway as I have a heap of threads with mild corrosion to clean up).
A quick clean up with an M8 x 1.25 tap and the bolt went in fine. The problem was the pin was quite hard to remove. Instead of using brute force, I elected to extract using the nut and washer working against the face of the hole. Once fully against the washer, the pin tapped out as per the other side. I couldn''t see any reason for the difficulty, so I am curious as to whether the exhaust side is hotter and/or dirtier. This pin actually smelt different, much like a diesel locomotive.
I also noticed some damage to this area. The bottom of the mounting face has a big dent on it, in fact it has deformed all the way through to the inside, and had caused the mounting face to rise. Above is after a couple of minutes of light file action to remove this. The slight deformation does encroach the gap around the oil gallery bolt, but not greatly.
I have checked the deck level (really good) and the valves seal I tested with fluid (in my case not water, but pouring degreasing fluid back through the inlet and exhaust ports) and did not leak. Despite the slight damage to one cooling fin, this appears to be a good head. Just need to remove the vales and check the valves and spring tolerances.
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