At LS Fest back in September, I developed a knock after a pull where I let out due to some noise I though was detonation. Upon inspection, I found #2 plug's ground strap a little melted and lots of metal in the oil and filter. Being that the metal flakes were both steel and aluminum, discussion with the guys at SAM thinking I may have had the King tri-metal main bearings on one/some were spun even though my oil pressure hadn't changed. I get the truck home, start tearing it down and this is what I find...
Odd bank (7,5,3,1)


Even bank (2,4,6,8)


Bad 1&2


#2 bottom


#1 bottom


#1 top


#2 top

 

Now on to the cylinders....

#1










#2









Most of the marks are material transfer from the pistons and they cylinders don't seem to be scored. I picked up some muratic acid I am going to use to get the aluminum off without abrasives to get a better idea of what shape the cylinders are actually in.

 

So what do you think the caused this?

 

man thats heart breaking trust me i know the feeling, wish ya better luck on the total rebuild !

 

Looks like a clearence issue

 

It could be a combination of things. Looking at the scuffing on 3-8, it could have been a really close bore clearance. Combine that with the way the KB manifold feeds directly over 1&2, running a heat range too hot plug (BR6EF), a set of hand ported heads which may be inconsistent between runners and spraying it with a 50 shot on that last pass probably all contributed to the perfect piston swelling storm that allow the pistons to make contact with the wall.

 

2618 or 4032?

 

I believe they are 2618. They are Wiseco -11cc 4.030 bore turbo pistons. PN on piston is 6444H3.

 

I got the crank out and the bores cleaned up today.

Main bearings have some wear. I believe the pitting in #1 is from the piston debris in the oil.


Crank looks ok to me. I cannot feel anything with my nail on #1.


Block side bearings. I didn't get a pic but the thrust bearing had hardly any wear.


#2 top side after cleaning


#1 bottom side before cleaning


#1 bottom after cleaning


#2 bottom before


#2 bottom after


#1 top before


#1 top after.


I can feel a little texture in #2 bottom and #1 top sides. I think it may be a little more than just a hone can get. Hopefully I can get it with a .005 overbore as Wiseco has an off the shelf 4.035 bore -11cc piston. Regardless, it needs to go to the machine shop.

 

That sucks man , so crank and cam are ok ?

I just don't trust anyone other than GM built long blocks , too many I've seen have problems. I'd just find a stock long block and go have fun again for not much money . I'm not saying there aren't good shops that can build them though.