Main bearing wear question

[jdblood202]

Well. I bought a "built" shortblock from a member here, I know, I really should have checked this when I bought it. I was short on time and rushing a little though so it's my fault. The block was allegedly used under 8k miles in a 500hp build. Weisco pistons, Eagle rods, ACL bearings.
I was actually about to use it, decided to pop the main caps and take a look at the bearings, (future notice, do this before I buy a motor next time), and I need advice from someone a bit more experienced in motor building than I am. A couple questions I have, is this "normal" wear or is there something wrong that needs to be addressed? What do I need to do to fix it, obviously new bearings, I'm assuming crank will need to be machined? Also, one of the rods had a bit more side to side play than the others, I measured it, and it's right at the service limit. Do I need a new rod? How does that happen? Anyways, I'll post the pics I took, I didn't pop the rod caps off, I'll do that later.

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[jdblood202]

I didn't take alot of pictures of the crank journals, but these are the couple I did take.

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[jdblood202]

Also, this is the rod that I was questioning side to side clearance on.

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[donniekak]

That varnish didn’t build up in a few thousand miles. They probably just dropped in rods and pistons. The bearings are chewed up from dirty assembly.

 

[jdblood202]

Now, on the crank journals, if my finger nail catches on anything it needs to be turned?

 

[donniekak]

Usually.

 

[jdblood202]

Ok, what about that connecting rod side to side play? Is that an issue with the crankshaft or the rod itself?

 

[donniekak]

Measure the big end width of all the rods.

 

[motomattx]

There was alot of dirt in that engine, the side play on the rod I wouldnt worry all that much on, its just poor quality control from the Chinese Eagle rods and shouldnt change much. You dont turn 6 bolt cranks, they are nitrided, so I wouldnt bother turning it to be honest, I would look for a replacement or possibly see if it can be polished out by a machine shop and then if it can buy new good quality bearings and check the clearances with them installed.

 

[ThunderChild]

Honestly I'd have the crank checked and maybe polished, it doesn't look too bad. Those bearings are pretty trashed. Might be able to get away with a new set and polish on the journals, but you're now going to want to tear the whole thing down and check/clean it before reassembly and use.

 

[jdblood202]

Ok. I'll bring the crank to a machine shop and see what they say. What's a good recommendation for clearances? Honestly, this build isn't going to be crazy at all. I'll be sticking with the 14b until I have enough for a 16g, that's probably as big as I'll go. I see alot of guys setting clearance to .002, is that too tight for a stockish build?

 

[jdblood202]

Now, I want to assemble this motor on my own. After seeing those bearings and with the general consensus being the motor was dirty on assembly, how do I avoid making the same mistake? What are some methods/techniques you guys use to make sure the motor is as clean as possible on assembly?

 

[Vegas Smith]

Might as well have the machine shop assemble it for you so it get's done right if you're not familiar with engine assembly.... or not assemble it in a sand storm

 

[motomattx]

Have the block hot tanked and checked for straight on the head mating surface, after you get it back run it through a pressure washer at a car wash to make sure every passage is power washed out, then run a can of brake cleaner through every oil passage, then dry it really good and paint it after 24 hours if you want to, flash rust will happen unless you immediately oil the cylinder walls and head mating surface with at least Wd-40. I would go with .0025 to .003.

 

[Tyeler18]

Along with ensuring the block is thoroughly clean, Id have the machine shop remove the weight balls in the crank and clean all the passages. If this engine was built because it lost a rod/main bearing, chances are the debris that tore up the bearings was material stuck in the crank passages. No amount of cleanliness on the block/exterior of the block would prevent that from happening if so. It's amazing how much garbage gets trapped in that passage and people end up looking past it or not realizing they're cleanable.