Whilst agreeing with most of the comments above, I'm a little skeptical about the supposed G20/19 diesel-irrespective of whether it is standard or RC. G20/19 and G20/23 glows certainly-but I note that the rods on the 'oversized' versions tend to be 'shaved' at the bottom end to cope with the increased crank throw yet still achieve clearance within the case. I suspect that a diesel version, with its higher running stresses and rod loadings, might be too much for a 'shaved' conrod to cope with. This is based on observations of my own G15/19s-and an early (1950s) G20/19 glow like the one sold by brokenenglish above. I agree that the 19 glows are very thin on the ground-whether G20 or G15.......and I'm not yet convinced that a G20/19D exists..........
ChrisM
'ffkiwi'