The 4BE1 is an "interference engine." If you are performing a rebuild, always double-check your on the front timing cover before rotating the crankshaft to avoid internal damage.
Bring Cylinder 1 to Top Dead Center (TDC) on the compression stroke. Isuzu 4be1 Engine Repair Manual
Internal clearances within the oil pump assembly can exceed factory limits, lowering total system pressure. Step-by-Step Engine Overhaul Procedure The 4BE1 is an "interference engine
When performing a top-end or complete bottom-end overhaul, cleanliness is critical. Label all components during removal. Cylinder Head and Valve Train Isuzu 4be1 Engine Repair Manual