Originally Posted by
OddDuck
Fitting pistons to cylinders, fitting base gaskets to engine.
The base gaskets are there to seal against oil leaks, they don't deal with gas pressure. Ducati use Loctite 510 as a sealant, that's the bright pink beads visible in the photograph. I've kept the assembly stock, with 0.4 mm gaskets used on both horizontal and vertical heads. It's possible to modify squish and marginally increase compression by omitting these gaskets or DIY'ing something out of thinner metal, but the price paid for that is vulnerability to impacting heads and pistons, if the engine has any coking due to running rich. Best restricted to race engines which are torn down frequently.
Getting the pistons into the cylinders was a bit fiddly, until I learned the trick: slightly misalign the cheap Stanley piston ring compressor's leaves. This has to be done because Ducati left a generous 45 degree chamfer on entry to the cylinder bore. The rings like to pop out of the compressor and bind up on this chamfer during the push... it'd be very easy to try to force it and break a ring, carve up the cylinder, damage a piston ring land, or some horrible combination of all three.
If it jams during assembly, just pull it, get it back into the compressor, take the time and set it up right. It'll go in once it's lined up, with those compressor leaves actually in the 45 degree chamfer but stopping short of the gentler taper leading into the main bore. Cylinder and compressor were wiped down and oiled before assembly, with ring gaps set at 120 degrees to each other in their lands, as per the workshop manual.
It's not really possible to put pistons onto conrods and then lower the barrels over them, unless some kind of split-half ring compressor is available - something that can go in past the studs and come out again between them.
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