Questions about Crankshaft Bearing

I am currently going to replace my Crankshaft bearings.

When I go to order the part from Toyota, whether online or in person. They ask me Mark 1, Mark 2, Mark 3 or Mark 4. The only other information I can get on differentiating the difference is “Refer to Repair Manual.”

Thank you for your time, and have a wonderful day!

Also, I apologize if this was posted in the wrong spot!

 

Hey sorry about the 5 months of blackout from my end. It’s been a long rough winter here in South Dakota. But, I am here to provide an update..

My 2005 Prius has roughly 350,000 miles on it.

I thank you guys for the insight I truly do.


Now, as for what happened. I was driving up a Rather steep hill out of cell service. As I created the hill, dash board lit up and you could hear the sound of metal crashing. I slowed down and pulled off the side of the road. Grabbed the OBDII from under my seat and plugged it in; I got a code for the camshaft position being off. I cleared the code, turned the vehicle off. Let it sit for a bit, letting the weight of the situation set in. I start it up again, the ICE fired up.. nothing. No noise! Phew! I gave it a little gas, still parked and still nothing. I get back on the road and take it slow. About a mile down the road, the dash lit up again, metal on metal banging. I pull off shut it off and I’m now in cell service. I phone roadside and get towed home at 4am.

The next morning, I pull the valve cover off and holy guacamole, there’s metal everywhere! I drain the oil, there’s not a whole lot of metal in the bottom and but it’s present. So I take the opportunity, and start to pull it apart. After surprisingly very little work, the timing cover (oil pump housing as Toyota calls it) comes off. The inside is just riddled with metal. The auto adjusted for the timing chain fully extended, and the chain is pretty limp. The chain guides have obvious wear in them. Each individual chain link shredded/excessively worn. I pull the head off, every single valve now bent. Yeehaw. Minimal damage to the top of the piston head. After complete disassembly of the head, dropped it off at the machine shop. It all checked out. new valves, springs, and retainers. I had to replace like 9 of the buckets?

The head now has optimal clearances. And the valves passed the water hold test.

I then removed the upper oil pain. To check the low end bearings. Connecting rod ones bearing is extremely worn. I take the opportunity to change em all. All the bearing clearances check out. Slap it together, torque it down and fill it. She runs like a dream.

I take it out for a test drive, two miles down the road. An audible crunch. And then some rod smacking.

Upon one more tear down, I find the first connecting rod Bearing housing to be ovaled by just a hair. But, now the crankshaft journal is beyond jacked. Now each and every bearing is completely screwed. The journal for piston 1, is now spec’d outside the realm of an undersized bearing available for the Prius or scion. And now one here or nearby does crankshaft repair. So I picked up a new crankshaft, all new set of bearings, pistons and oil seal.

All of the clearances check out. And the engine is almost back together.

The only things that I have not replaced are: Flywheel and Damper, camshafts, and the bulky block parts of the engine. I’ll drop one more update by Saturday as it will be done by then.

Again thank you for all the info, sorry about the length of the post and that the background for the question came five months later.