Paul,
The liners do not creep by themselves, they would have been in place when the head was removed. The interferance fit is quite generous, to the order of around 0.06-0.08mm. I have bored barrels for over-size liners, but can't remember exact numbers, would need to check my notes. The massive contact area assures that the liner will not move without a considerable amount of heat being introduced to the casting. They should not move simply by placing the barrel assembly with the liner bottoms on a workbench.
Either the interferance fit was not ample to begin with (which I seriously doubt), or the barrel casting has suffered from the fire, compromising the fit.
Two definite problems may arise from this. Assuming the interferance fit is OK, simply shifting the liner back may distort the bore. Removing said liner completely to check the fit will almost certainly cause distortion! If the liner is too loose, heat transfer from liner to casting will be drastically compromised with possible piston seizure resulting. With the engine running, the barrel will undergo similar conditions as in an oven. Clearance between liner and casting will increase, allowing oil to ingress, which will eventually bake in place, further reducing heat transfer.
Transferring the liners to another barrel casting is also problem-prone. The bores will surely be distorted.
Nothing is as simple as it first looks...
@ Greg, the head is always flat, save for the recess for the liner spigot that fits into the circumference of the combustion chamber. While the height of the spigot is rarely critical, skimming the head excessively can change that. In stock form, there is a gap of about 0.5mm between the upper edge of the liner spigot and the combustion chamber. The liner recess in the barrel gasket surface is filled by the flame ring of the (correct-type) gasket. Besides, in Pauls pic, the 3 liners are clearly all at different heights.
piet
