If that is not rod knock I'll eat my hat, sorry mate but that sounds grim

 

It may not be rod knock, had the exact same sound on my subaru 3 months ago, vid for proof.
https://youtu.be/ZmyepZdHDJ4
Everyone thought it was rod knock so I decided to rebuild the engine.
Took it all apart to find the crank and bearings in perfect condition, turned out to be the valve guides being messed up and the valves hitting the pistons possibly due to the timing belt skipping a tooth.
So i got the heads reworked and what not, replaced all gaskets, piston rings, water pump, oil pump and timing belt, so I buttoned everything back up and it runs just fine now.
I think you may need to, either, start taking stuff off to get a look inside or take it to a shop and have them look if you're not comfortable doing it yourself but I'm thinking it may also be the tensioner as well.
Best of luck mate, hope you don't need a new engine.

 

Thanks guys,
I will tow it to the shop next week and have them look at it. I don't have the time and space to take the engine block apart.
Will let you know what they find.

 

None of you was even close! Well, FZXtreme was kinda' close.
Turned out to be a few broken cam gear teeth. Big ups to Mark at One6(onesixmotorsports.com). They put new gears in - engine humming like new.

Thanks all!

 

What the heck caused that? What was the condition of the timing chain?

 

I have no Idea how that happened. When we replaced the valve retainers we put the shafts back in very carefully making sure all lines were lined up to TDC. Torqued everything to specs and turned the engine by hand making sure everything was smooth. I drove the car like I stole it for several days - everything was fine, running like a champ. Then one day all the sudden this noise came. I am thinking my torque wrench sucks and a possibility of over torque, but I am just speculating. I am very particular and careful when I work on my cars.

 

Can i ask how much did you got it fix for. And where. I live in san diego california i my s2k has a very similar engine noise. It drives fine but it does have that problem thats why i parked it. They told me i need a rebuild or a new used engine.

 

I'm really surprised that isn't rod knock. I guess rod knock is a little more intermittent than what you are hearing. Good job finding out the issue.