Engine parts suppliers

Hi all.
Forgive the long absence. I lost all on the PC and its taken me a while to get up and running.
I have a J63D Espace 2. THe engine suddenly cracked a liner (number 2 cyl) for no reason. When I removed the cylinder head i noticed that its due to under use of correct coolant over the years. This is before my ownership.

To the point, I would like to hear from anyone that could offer part suppliers in Europe (on line catalogues if possible) that I could possibly contact to get the replacement parts. Renault original parts are very expensive. There must be suppliers out there willing to supply these items. For example: pistons/ liners/ oil pump/ camshaft.

regards.
Espaceman