hellspare

Hey guys. So a while ago my engine spun a bearing due to low oil, and I had to rebuild the shortblock. So all that was done, and after break in I took it above 6k for the first time. Right after I got off the freeway I start hearing this light knocking sound. I tried replacing the TCT, pulled apart the vtec solenoid, examined the valves, nothing changed the sound.

As for the sound, I can only hear it during cold startups,(it rattles for a second or two then calms down) during idle(a light tick tick tick sound, about 4 times a second), and under light throttle from 2.5-4k. Under load or above that rpm I can't hear it at all. I do have a pretty loud exhaust, but the drone goes away after 6k, and I just don't hear the sound up that high.

Any idea what it could be? Keep in mind I only hear it in certain rpms, it doesn't continue to get louder past 4kish. I read about the 4th cylinder failure that these cars sometimes have, could it be that?

fatjoe10

Sounds like piston slap, but I'll let the experts chime in... do you have any info on how the engine was put together, particularly regarding piston/cylinder wall reconditioning if any?

hellspare

My crank was crowned, and new aftermarket bearings were put in for the new clearances. I don't know anything about the piston/cylinder wall. What errors in that process could have caused this?

fatjoe10

For example, if the shop rehoned the block without following Honda's recommendation for FRM cyl walls, they can get scored by the piston and thus increasing the clearance enough to make the piston rattle in the bore. These blocks are very picky when it comes to honing/boring over. In fact, it is difficult to find a shop that will properly deal with them.

Not saying this is your problem, but this is one scenario. A vid would be helpful

nicks2k2000

i know i may sound stupid but it may have nothing to do with you engine it could be a heat sheild on your exhaust may have broken loose after you took it up yo speed and made an unrelated noise to your engine. cause i would imagine that your car was siting for a while, while your engine was out or your car and it rusted you heat sheild just enough

hellspare

I will take a video when I get the chance.

hellspare

How much roughly would it be to rebuild? Would this be cheaper than buying a new engine? Because my tranny is still good, and I'm assuming many parts in my engine are still good also. When rebuilding they'd only have to replace the parts that are bad right?

hellspare

So I uploaded a video of the sound. I know the quality is bad, as it was recorded with my phone.

http://tinypic.com/player.php?v=33lj81s&s=6

Let me know what you guys think.

RedY2KS2k

Sounds expensive to me.

bgoetz

That almost sounded like the TCT, until you reved it. hmmm, this is a difficult situation, have you talked with the people who built your engine?