This old Skoda engine I'm rebuilding has wet cylinder liners, and uses thin copper shims in their seats. The manual talks about liners protrusion between 0.14 to 0.32 mm above the block, and available shims between 0.10 to 0.14 mm. When I inserted and homed the new liners I will install, I realized they already protrude above the block WITHOUT any shim on their seats. The old liners do have the shims, and even with them, they protrusion was almost in-existent. All the old liners got also silicone gasket maker in there as well.
I think I will use silicone gasket maker for the new liners too, since I guess the seats and the liners may not get a perfect fit. But my question is, well, if I get the liners protruding without shims...do I still need them? I'm concerned about the height shims + silicone gasket may add.
Edit: I found this in a Volvo trucks manual: "If the cylinder liner is installed without a shim, an even strand of jointing compound, approximately 0.8 mm thick, should be applied to the underside of the cylinder liner collar."
Edit: So I measured everything carefully today. The old liners:
- The overall height is the same
- The outside diameters are the same
- The height between the top and the seat bevel are different:
- Old is 94.6 mm and the new is 95 mm
So 0.4 mm is the difference. Curiously, the new liners protrusion against the block at top without shim is 0.4 mm. The manual says 0.15 to 0.2. Photo showing old and "new" liners.
The old shims are homemade.
The manual says right length between top and seat to be 95 mm, so the new ones are good. I wonder if the block got rectified its top surface...