Backstory is I was getting low oil pressure and when I cut open the filter there were a lot of metal shavings, copper colored inside. I finished putting my 5.3 back in this morning and now its time for the teardown of the 408.

All the fun in the pan...


Main caps, front on the right, need to remove the rear cover before I can take the back cap off...


Crank...


Pretty sure I found the issue....but the real question is what caused it? Bearings are clevite mb3591H

Also, its is necessary to tear down the rest since I found the bad bearing?

 

oh man that looks like a bad deal how long was the motor in and running for?

 

Any idea what the bearing clearances are set at?

 

You really should tear it down to the bare block, you need to check the cam bearings too. Also really needs to have all of the oil passages cleaned out by a machine shop. When you put everything back together, it would be wise to check the clearances on everything as you go. I'd have the crank checked also.

 

In the top pic, the bearing is installed backwards in the cap. Not sure if it was installed that way in the engine, or if you just set it down like that. Also, looking at the main caps, they look black. Might just be the camera lighting or something else, but if they are actually black, then they got really hot. I think I see the same thing on the block, but it's hard to tell. If the main caps got hot enough to turn black, then it's usually necessary to line-bore the main journals.

Don't just slap new bearings in it.

 

Motor was run for 1.5 months, 1700 miles.

No idea about clearances. The bearings are indeed black.

 

damn man......just tear it apart and have a machine shop check everything. worse case...just make a 427

 

Did you buy this shortblock used? Or "fresh built"? It appears that it likely was slapped together without checking anything along the way.

Black main caps = death of next rebuild, unless you get it machined.

 

Damn man that sucks bad. I was just talking about this last night and how I will never build a motor, I'd just get a 6.0.

 

How do you get the rod caps off? Having an issue with that...

I bought the shortblock brand new....any shops in AL anyone recommends?