Originally Posted By: mjoekingz28
Exactly! The belt on an interference engine is what held me back on loving a Honda Civic. Anyone know up to what year they were belt timed?
Also, for some reason, I always thought DOHC = 4 valve and SOHC was 2-3 valves. OHV was always 2
The Civic in particular went to a chain with the new R18 engine in 2006. All of Honda's engine families have been moving to chains (along with "normal" clockwise rotation) as they've been replaced starting in 2001 or so IIRC. Only the V6 remains w/ a belt.
As far as SOHC vs DOHC with 4 valves: Honda, Mitsubishi, and Subaru in particular stand out as manufacturers who have produced SOHC 4 valve heads recently. I'm not sure what the reasons are but I'd guess it has to do with cost and size. I don't know how much of a cost difference it makes but I do know that if you compare this engine with, for instance, a K series or the Mazda MZR series (DOHC) the head is *much* narrower on the SOHC one which is nice for tighter engine bays.
What's really crazy is I think the 6.7 liter diesel V8 in the new Chevy trucks is an OHV motor -- with 32 valves (4 per cylinder)!