Whilst driving the Lika the other day, in forward gear, the ride became increasingly jerky, but it was OK in reverse. I found that steam was not entering the top of the left cylinder in forward, but was in reverse. Mystified, I thought the return crank had slipped (square peg in square hole turning into round peg in square hole). It hadn't, so I opened up the left steam chest and found the top lock nuts had come loose. so the valve rod was somehow driving the valve OK in reverse but not in forward. Apparently lock-nutting is an unreliable method of preventing a nut from rotating on a thread however tightly forced together, and it is too hot in there for Loctite to work reliably. I removed all the stainless locating nuts and drilled and tapped M4 into the side of them, replaced them and reset the valves, and fitted a grub screw into the side of each nut thus pinching the nut to the valve rod, so preventing it from rotating. It seems to have worked. Castellated nuts and split pins in a hole drilled in the rod would work the same, but might weaken the rod.
- Number of posts : 23
Location : Tillingham, Essex
Registration date : 2008-06-20
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