Yeah SOHC's drive the inlet and exhaust valves off the same cam. Then again, there are only 12v on those I6's, so 2 valves per cyl isnt hard.
Granted, DOHC makes more sense, Aston Martin and Lotus were using DOHC engines in the 60's, its just taken longer for the 'lower levels' as it were, to catch up. Theres nothing wrong with an SOHC design, its simpler, so theres less to go wrong, potentially, but for pure power, you're not going to beat the DOHC engine design.
The successor to the M20 was the M50, with was even better, had DOHC, VANOS computer control after about 1993/4 and special versions were made into the S50 series for the M3's (US Spec 246hp, RoW Spec 326hp).
They do make a lovely noise as well
Granted, DOHC makes more sense, Aston Martin and Lotus were using DOHC engines in the 60's, its just taken longer for the 'lower levels' as it were, to catch up. Theres nothing wrong with an SOHC design, its simpler, so theres less to go wrong, potentially, but for pure power, you're not going to beat the DOHC engine design.
The successor to the M20 was the M50, with was even better, had DOHC, VANOS computer control after about 1993/4 and special versions were made into the S50 series for the M3's (US Spec 246hp, RoW Spec 326hp).
They do make a lovely noise as well
