Byneset Customs of Norway are now offering timing belt covers for B230 engines which have 16V heads.
The B234 timing gear covers don't fit on the B230 - the B234 covers have a lot of extra space for the balance shaft belt. These two-piece covers are purpose built for 16V conversions.
These covers, made to fit B230 family engines, come in four different versions:
1 – fully closed cover as pictured first. Stock crank pulley
2 – fully closed cover, with cutout for trigger wheel on custom crank pulley.
3 – open cam gear with screw on gear cover, for stock crank pulley
4 – open cam gear with screw on gear cover, for trigger wheel on custom crank pulley.
Priced at 4,500 NOK - about $652 AUD at time of posting - plus shipping, they're not cheap. But neither is replacing a bunch of bent valves, etc, after a rock has flipped up off of one of Australia's potholed goat-tracks and helped the timing belt break or otherwise work its way from the pulleys.
One of these covers is definitely on my shopping list for the 142 project; I figure it's worth it for peace of mind.
More information at the vendor's site, link below.
https://www.bynesetcustoms.com/B23016vdeksel.htm