BMC A-Series and NIssan C18DET - blood brothers!
Even having read cover to cover countless times, David Vizard's masterpiece on the BMC A-Series engine, I did not know that it was related to the much later Nissan C18DET (Of early 200SX fame).
Well the things you learn late on a Saturday night surfing the net. I was originally searching for stats on FIAT's legendary SOHC engine and somehow I ended up reading about that teenage obsession - the stalwart BMC A-Series.
In the words of Wikipedia "The A-series design was licensed by Nissan of Japan, along with other Austin designs. Improvements were rapid. An early change was to incorporate a 5 main bearing crank. The cylinder head was modified for the first of the E series by swapping plugs and ports, plugs fitted between pushrods and 8 ports eliminated the Siamesed inlet and exhaust ports. Nissan modified the design into the later Nissan A engine that was launched in 1966 with an aluminium head and wedge combustion chambers. It became the basis for many of their following engines notably the later OHC Nissan E engine, was scaled up into Nissan CA engine and ultimately the DOHC 170 bhp (127 kW) CA18DET. All these engines show their lineage by the characteristic un-skirted crankcase block of the BMC A series, "
I hope that was as interesting for you as it was for me ! They do share some characteristics, no matter how different on paper, the C18DET was a revvy thing and the A-Series was to, perhaps courtesy of the involvement of Weslake on the combustion chambers. If you don't have a good burn, you'll struggle to make a great engine. This is one of the reasons the BMC A-Series and FIAT SOHC can make such high HP per litre, for on paper both look old fashioned.