Want to make sure to get quality parts?
* Make sure the bearings are Datsun-spec F77 tri-metal and not cheap alumninum bearings
* Don't get fel-pro printoseal (ps) head gasket. Other Fel-Pro lines are top-notch

Your best bets are genuine Japanese brands, but american suppliers are usually good like Clevite 77 for bearings, Beck/Arnley is almost always packages Japan brands, Moog usually repackages Japanese parts ... in other words most stuff that RockAuto sells is OK, and the less expensive closeout parts are usually best. The cheap chinese stuff is becoming the new normal "regular stock"

Ok DD....you got me thinking about aftermarket bearings. I checked the tolerances for the main and rod bearings and they are all within specifications .038mm to .051mm which are the two closest measurements on the plastigage scale (Haynes manual has a maximum of .060mm for the rod clearance and tech wiki shows a maximum of 0.50mm ???). They all look in real good shape unless you see something out of the ordinary. No significant scratches that I can see. I dont mind spending money on a rebuild but if these bearings truly do last 500K miles and they are OEM Nissan parts, I may just put them back in the motor. I will have the machine shop polish them along with the crankshaft. The cam bearing closest to the timing chain has a couple grooves. Is this normal and some sort of oil passageway? this same bearing has a slight scratch which I hope can be polished out. Also all of the pistons has a slight yellowish color as pictured. Any concerns here? Everything goes to the machine shop tomorrow. Will have them mic the crankshaft and cylinder bores and get everything cleaned up including the GX and H89 head. And turn the flywheel. Will report back later.

Attach file:

---

  main.caps.jpg (58.53 KB)


  block.bearings.jpg (13.77 KB)


  crank.jpg (108.31 KB)


  cam.bearing.jpg (84.59 KB)


  piston.jpg (45.82 KB)

The wiki lists new bearing specs. The full service manual additionally lists service specs (maximum worn clearance which are still OK to run).

If yours are in the new bearing specs, why replace them? A lot of guys will say, for cheap insurance. But why fix what ain't broken?

I agree with you. Will see what the machine shop says. Are the grooves in the Cam bearing ok? And is the yellowish color on the pistons normal? When I disassembled the motor, I noticed a couple of the coolant passageways in the H89 head were clogged with a white substance and the water pump was seized. This motor likely overheated and dont know the extent of any damage, if any. After removing the valve springs, I had to tap out several of the intake valves from the valve guides. All the others came out good and felt snug. Will replace all valve stem seals.

Yes, the cam bearing need the grooves. They are not normally replaced during an overhaul

Yes, those look fairly typical for used pistons. Brown or black oil heat marks are common

Valves not coming right out usually mean previous owner did not regularly adjust the valve lash, and the tips of the valves got hammered

Be sure to measure (and probably will need to replace) the valve guides, which is the #1 wear spot in the A-series engine

Water pump seizing could be caused by rust. The most tell-tale of overheating is if the head is warped. To check for overheating damage do this:


When my engine massively overheated the head was warped 0.020 inch -- 10x the standard! Coolant ran out of the spark plug holes