British and Japanese shared engine families

It's fairly common knowledge that Datsun built A-series powerplants under licence to Austin. However, I just discovered last night that Isuzu built Hillman Minxes under license to Rootes until the early 1960s.

homepage.ntlworld.com/andymurkin/Hillman/Hillinfo/IsuzuMinx.html

So I did a bit of googling and discovered some photos of the engine from an Isuzu Bellet.



Which looks very similar to a Rootes 4 cylinder as found in Sceptres, Alpines, Hunters, Minxes etc.




Except that the Isuzu engines appear to have been continually developed and improved to include:

Better flowing inlet ports



Single Overhead Cams



And Double Overhead Cams



Isuzu also made other improvements such as doing away with the removable pushrod cover, thus strengthening the engine block. Interestingly, the top end versions of the Isuzu engines appear to have higher horsepower ratings than anything Rootes bolted together.


Likewise Datsun continually redesigned their A-series engines to include improvements such as 8 port cylinder heads




This of course is leading up the all important questions.

1. What other Japanese manufacturers based their engine designs closely on those of foreign manufacturers?

2. Is there much parts interchange between Japanese and foreign engines, particularly with respect to cylinder heads where the Japanese continued to develop and improve their engines?


Personally I would expect that cylinder heads should be adaptable, because even though the Japanese did redesign the various engines they inherited from BMC and Rootes, it appears that initially they kept the same basic block architecture, which would suggest that the key factors such as head bolt location and bore spacing shouldn't be an issue.