do not guess timing on any engines, or risk valve damage.
the service manual covers all this.
no year car told or country , (an Iisuzu FASTER class truck)
KB350 , is in Africa or Down Under? guess it is
3.5L V6 (gm?)
Just so you know, the books are by country , maker ,model , year and chapters on the engine option there.
we have no KB in the USA ,not one.
it broke the the cam belt or stripped it out my guess.
seems too you bent over valves.
which engine is there or "wiki isuzu engines" and find it and tell it first.
or buy the shop manual from Isuzu.
The 2006 up is GM and is Interference engine and now damaged,
is this post a bingo,, ?????? there are 2 types 3.5L,
may be wrong there is no African wiki for KB350 or for any Australian bakkie ether, so facts super hard to find, not living there.
just this but I think is 1999 ISUZU TROOPER
https://www.fixya.com/cars/t15182528-isuzu_kb_350_v6_cam_timing_settings
I bet a by hand , keys in pocket only fails a leak down test.
cylinder leak down tool (common and nails here)
cranked by hand only, gently. (no need to bend valves more)
i think your 3.5L is SOHC or DOHC cam with belt drive cams.
KB was sold in AUSTRIALIA BUT NO 3.5l
SO AFRICA KB , 2013?
OUR OLD TROOPER HAD 3.5 SOHC.
6VD1 SOLD SOHC AND DOHC VERSIONS BOTH.
OR
6VE1-W 3.5L
DOHC 24V V6 was introduced in 1998
AND SOME TO
AFRICA ARE GM ENGINES.
SORRY CAN'T GUESS YOURS THE WIKI IS (VACUUM HERE)