Hi all,
I have been slowly rebuilding a 3.4 that I am going to swap into my 92 4Runner. The donor engine is from a 97 4Runner. The donor block was completely machined, with a .020 piston overbore, and crank connecting rods had a .010 overbore. I think I am using the correct terms here. Anyways, when placing each piston, I made sure I had the correct clearance for connecting rod bearings using plastic-gauge, and they were all within spec, at .024 clearance, ish. Plastic-gauge is not an exact tool as far as I can tell. Additional, the main bearings were all within clearance spec as well. I went through the rebuilding process following the FSM as one does, finally got all of the swap stuff figured out, got the new engine installed. I ran the starter motor until I had oil pressure indicated on the dash, I'm not sure I had enough oil pressure in hindsight, and started the motor for real. I had a single cylinder fire before the engine promptly seized and couldn't break loose.

Sad day.

So I popped the engine out and tore it down, because that is a fun way to spend my weekends now, and got to the point where the pistons come out. The crank was locked up all the way until I removed pistons 1&2, before it loosened up, though it started to wiggle free after removing 3&4. So, easy enough, I checked for bearing damage on all bearings, and couldn't find any. No scratches, no hot marks , nothing. Plasti gauge clearance for 1&2 is still at .024. I was at a loss, until I saw the thrust washer. Photo is in the next comment, but it looks pretty thrashed. Have any of you ever seen a messed up thrust washer like this? Now when I try to put the crank in with the thrust washer, it just doesn't go in.

 

 

Update in case anyone is interested: I found where the binding is happening. The #4 cylinder bearing cap is pinched between the crankshaft counter weights, so it can't even fit onto the connecting rod. Bummer.