I have a D16z6 build to handle boost. Bought it used in need of a rebuild. I had it bored .020, 75.5 SRP forged pistons, eagle rods, had crank micropolished, and a professional builder assembeled the bearings & bottom end and did all the machine work. I have been driving it NA to break it in easy. it has 1600 miles, about 400 ago it started to get a little noisy. The noise got worse recently so I stopped driving it. It was definitely rod knock.
I was able to go through the bottom of the engine to check all the bearings so I wouldn't have to pull put the whole motor.
I called the builder and he said to bring in the bearings for him to look at.

Here's the tear down pics...





First lets have a close look at the main bearings and see what you all think...


some signs of wear, but I don't know from experience if that amount is normal or not.

I looked at the crank surfaces for any signs of wear...


main 1


main2


main3


main4


main5

And now on to the rods...
First I took pics of each rod end to look for signs of discoloring due to excessive heat...


rod #1


rod #2


rod #3



rod #4

Look at Rod #2 at the crank... it is a different color than the other pics, and you can see it again in the background of the rod #3 pic. #2 bearing is probably bad and generating a lot of heat, but the rod end looks normal even though the crank looks like it saw some high temperatures.

Now for the Rod Bearings:





Rod #1 Bearings




There's the crank surface for the #1 Rod bearings.






#2 Rod Bearings


There's the crank surface for the #2 Rod bearings. This is the one that got hot and discolored.




#3 Rod Bearings


Crank surface for the #3 Rod bearings.




#4 Rod Bearings




Crank surface for the #4 Rod bearings.

#2 is surely where the knock was coming from. I'm going to bring the bearings to the builder next weekend. I wanted to get some opinions from you guys too.
Do I need to have the crank micropolished, or does the surface look ok?
I've only seen used bearings that were in horrible condition, how do my bearings look (I know #2 rod bearing is bad, what about the others, do they look to have "normal" wear?)




Modified by teal_dx at 11:40 AM 9/7/2007

 

i would polish the crank, ive seen worst but it should clean up, cut and maybe go undersized on the rod bearings but have it measured first

 

looks like all the bearings are hurtin a bit for only 1600 miles n/a

if it were me in your shoes I would pull the motor back out, have the crank re-polished and the have the crank re-nitrated(spell?) to restore the coating that is on the crank if it were factory

can you catch a fingernail on any marks on the crankshaft?
what bearings are you using?

also when this motor was built the first time were the bearing specs checked with plasti-gague or was it done with a micrometer and a dial bore indicator?

my b18c is in ten times worse shape and still fixable...sucks though you only got 1600 n/a miles out of it