No. For higher compression ratios, you just need different pistons and cylinder head design.
On diesels combustion chamber pressures are far higher than an equivalent petrol, so the rest of the engine has to be 'beefed up' to cope with the higher forces. If you used an engine with the same...
As has been said, 500cc is a sweet spot for diesel engines.
But the 1900 did originally come from the fact alot of disels were based around the equivalent 2.0 petrol. To minimise costs, similar tooling was used, which meant that things like boring jigs, which were set-up to machine bore spacing...
