Ideally, you would have access to a R-1830 overhaul manual or something similar, as that would provide the best information on how to take one apart (
this place could help. I haven't tried them myself though). That being said.... engines that have not been looked after for a while may not respond as you would like to regular disassemble practices. I too think you could try the Tech Log or E&T section. Other options are the
WIX forum or the
Historic section on UKAR as you may well find several spanner wielders in those places. The original Flypast forums were always a good place too, before Key butchered it.
Edit:
some manuals here as well, but not the overhaul one.