I would add that on the J32A1 I had in my '00 Acura 3.2TL, there was a cam lobe for each of the 4 valves/cyl plus the VTEC cam lobe... 5 cam lobes/cyl:
Honda use "antique" jam-nut adjusted rocker arms to accommodate the VTEC action. I might assume the cheap 1.8l follows suit - but I have not researched.
Jam-nut rockers are an easier for home mechanic servicing than Toyota 2.4L/2.5L simple SUB DOHC that require special tools or dissassemby of the cam box to change tappet shims - plus this design can be noisy and demonstated high wear at cold starts. I recall Toyota went to hydraulic camshaft finger followers with 20 grade oil spec
My Nissan Rogue truck spec QR25DE is inverted bucket DOHC also.
Honda loves this setup. The D/F/L/J and some C engines are all 4 valve SOHC, with only a few exceptions (L15B/F20/F22 are DOHC, some early Ds were 3 valve I think). Chrysler did this on the 3.5/4.0. Subaru did this for nearly all non-turbo versions of the EJ. I believe some Mitsubishi engines from the 80s and 90s were too. And don't forget the classic Rolls Royce Merlin from WW2!
The main annoyance with making this setup is the complicated rocker assemblies needed to drive 2 valves from one lobe at the same time. I imagine it also puts stricter limits on valve angles/sizes and port shape when compared to a DOHC. Nice simple timing setup though.
Very common and simple but, didn't allow for individual duration of intake and exhaust valve openings. we do anything to get another 0.1 mpg and 2% hp these days but, at the cost of more complication. Ed