It has 250k on it. A valve spring broke in March and a new head was put on. All was well until last week, great gas mileage, etc. Last week it started making a knocking noise from the bottom end. At low idle there is no noise, but once you give it a little throttle it starts knocking pretty good. No CEL, it's responsive and drives normal. There is also a lot of blow by coming out of the filler cap. Much more than normal. PCV was changed and made no difference.

What does it sound like? Wrist pin...rod bearing, etc? In the 2nd video you can hear the normal valve slap at first then the louder knock comes in.

 

Sounds just like how my engine sounds right now. Any one have any suggestions?

 

Honestly it sounds like a rod bearing knock. How many miles are on your engine rest? Was it always abused? Revved high? Ran low on oil? Or it could simply just be age-wear.

If you google more videos on Honda rod bearing knock it sounds alike.

 

Honestly, I think the engine was abused, can it be fixed?