Sounds like a great project. Saving another one from a scrapper!
The lower oil pan is easy to remove even in the car, those front upper oil pan bolts can vibrate free. That lets the upper oil pan gasket slide out of position. Since that gasket also seals the primary oil passage above the oil pump, you'll lose oil pressure back into the oil pan instead of lubricating the motor. A bit of blue Loctite on those 3-4 bolts will fit the bill nicely. Plus you'll get to see how many bolts are sitting in the pan. They usually engrave scars on the lower pan when they get wedged under the oil pickup.
I'd definitely check the cam chain over very well. That was another weak point on the early M42. If it has the updated plastic style cam guides and some decent flats on the cam gears, I'd leave it as-is.
I'd also strongly consider replacing the water pump, plastic coolant manifold and deleting the vac hose pre-heater mess under the intake. And any motor swap is also a great time to replace the clutch, tranny seals and rear main seal.
As far as cosmetics, I'd also replace the oil filter housing seals - the gasket and o-ring both tend to leak. An OEM gasket with some Hylomar should button that up nicely.
Topic: m42 replacement engine.. questions on what to replace (Read 3382 times)