I have no idea what really happend to my motor. That is why I have brought my problems here to Honda tech. Ok here is my setup because I know everyone will ask.
B20 Block
Darton sleeves bored to 84.5mm
Wiseco 84.5 mm pistons 12:1 compression
Eagle rods with arp bolts
Arp head studs
LS crank and all brand new bearings.

I have a built b16 head, but the head was not damaged at all so that shouldnt matter. Basically what happened was I was out one night beating on the car a little and I heard what I thought was a rod knock. So I tore the motor down only to find all my bearings are perfect. I was a little confused so I pulled the head. No problems with the head. Then I looked at the cylinder walls all four cylinders where slightly scored. I thought that was weird. So I look a little closer and my number 3 cylinder is grooved to ****. I pulled the piston and this is what it looked like...



One side



same side no flash



Other side



That side again no flash


Top of piston.

So really I have no idea what happend. The car was always warmed up before driving to avoid extreme piston slap. I never lost oil pressure. There were absolutley no signs of detonation. The motor was tunned properly. So if anyone has any idea what the hell happend please let me know.

 

Were the pistons and rods installed correctly? How long did the motor last?

 

ouch had the same problem with one of ours i dunno what happened but we just bored it over and threw in some new pistons and now its running great.

 

Yes they were installed correctly. The motor lasted about 5,000 miles. I was just thinking that maybe the p/w clearance was to much and the piston finally just started slapping around in there.

 

yeah thats what i was thinkin maybe the bore was alittle off and the piston had to much play.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smileycvc &raquo;</TD></TR><TR><TD CLASS="quote">Yes they were installed correctly. The motor lasted about 5,000 miles. I was just thinking that maybe the p/w clearance was to much and the piston finally just started slapping around in there. </TD></TR></TABLE>

That piston wasn't "slapping around"... It looks more like it got run dry/hot... You had either some tight clearances or oil issues.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hybrid93Eg &raquo;</TD></TR><TR><TD CLASS="quote">

That piston wasn't "slapping around"... It looks more like it got run dry/hot... You had either some tight clearances or oil issues.</TD></TR></TABLE>

Hmm really then I wonder what that knocking sound was. O yeah im pretty sure it was piston slap. My oil was at 80 psi when the knock began to happen, and my oil level was perfect.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smileycvc &raquo;</TD></TR><TR><TD CLASS="quote">

Hmm really then I wonder what that knocking sound was. O yeah im pretty sure it was piston slap. My oil was at 80 psi when the knock began to happen, and my oil level was perfect. </TD></TR></TABLE>

Hey, you clearly know more about engine building then I do. I haven't been doing this for years or anything. I wonder why you even posted to get "help" with such a huge knowledge of the subject?