Exhaust Manifold!!!

[coyotekk]

I own a 81 280zx 2+2 and while racing my friend home something flew off my exhaust manifold!:confused:. At the next light I took off and noticed a very loud leak from under the hood. When I got home I noticed about a 1 1/2 in hole in the exhaust manifold where it comes of the head. I have no idea what was there. I have looked for pics of this part but have had no luck finding any. If anyone has any clue as to what this part is i would greatly apprieciate it.

Thanks, Kurt

[sblake01]

EGR valve?
http://i37.tinypic.com/13yhu8o.jpg

[coyotekk]

no thats not it. It's on the exhaust manifold above where it connects to the pipe.

[sblake01]

The only other thing I can think of is the exhaust gas sensor which is what Nissan called the front O2 sensor. Try an auto parts store because the OEM sensor is somewhat pricey from Nissan (if it's still available). About $35-$40 vs. about $115-$140.
http://i36.tinypic.com/2e1xes3.jpg

[coyotekk]

the O2 sensor is still there. it's on the manifold itself before it connectd to the pipe. Thanks for your help.

[sblake01]

Okay, I'll take one last attempt since I'm only guessing at this point. Could it be the metal tube that goes from the base of the EGR housing on the intake to the bung on the back of the exhaust manifold? If not, without a picture, I'm out of guesses.
http://i35.tinypic.com/295z49j.jpg

[coyotekk]

I found out what it was. apparently someone relocated the o2 sensor to the pipe and pluged where it went on the exhaust manifold. I thank you so much for all your help. One more question, There are several manifolds for the 81 280zx. how do i know which one will fit my car?