About 500 miles on a fully rebuilt lower end and freshened head. New pistons, con rods, honed bores, reconditioned crank, bearings/rings, new TCT. This noise is reminiscent of when I spun a con rod bearing in the original motor, but it's not nearly as loud. The noise comes in above 3K when free revving in neutral, and comes in lower rpm under load. Listen to the clip and let me know what you think.

This is a noise that recently developed. Car is down on power, VTEC doesn't engage. Car was running great until a week ago. Please share your thoughts after listening to the clip.

 

That's knock, I guess vtec doesn't engage because oil pressure is too low.

 

all oem components in rebuild?

 

I'm not sure where to begin, but I'm guessing to start with removing the valve cover and inspect, check valve adjustment. All OEM parts purchased for the rebuild.

 

Maybe wrong bearing size used, did you go from the crank codes,as would be incorrect if its been machined.
Did you use plastigauge

 

I don't know if plastigauge was used. I can ask the tech that did the build. All parts were given to the machine shop. They selected bearings according to the tolerances in my understanding. I'm using ARP rod bolts, and the shop tightened and check for spec using them too. So what I'm hearing is most likely a con rod bearing issue is what the knocking is coming from. I'm going to drain the oil and pull the VTEC solenoid and look for metal bits. After the time and money spent on this build, kinda wishing I threw in a used motor and rolled the dice that way.

 

UPDATE: I drained the oil through a strainer today and there were zero metal bits or fragments. I shined a flashlight into the oil and there was no "night sky" appearance. I carefully poured the oil from the catch pan into another container to see if any metal particles would remain on the bottom of the pan. There were no metal particles whatsoever. So the motor is making the sound of rod knock, but I have yet to see any evidence of bearing degradation. I'm taking the car back to the tech (via flatbed truck). He will run many tests, remove the oil pan, check valve gaps, and pull the head if needed. I used ARP head bolts so they can be reused. I'll update this post and the diagnosis continues.

 

since vtec is not engaging I'd check the oil pressure, and/or check the vtec solenoid screen. Simple check.

 

 

The oil light isn't coming on. How do you check oil pressure? I'm sure my tech knows, but thought I could diagnose before sending the car back to him. I'll pull the VTEC solenoid and check the screen for debris. I would think if there's debris up there, I would also find some in the oil when drained.