Someone trying to sell me used twin turbos of his rx7 told me its normal to have a crack on the mianifold where the gasket would be placed for the downpipe. His other pair had the same crack and he said every rx7 has that is this true? My shop said a crack in the manifold can only grow and is a problem and not usable

 

The cast iron piece that fits between the turbos cracks and is typically not a problem. The cracks can grow to appear HUGE and still not be a problem. It usually cracks on the side that mates with the exhaust manifold that bolts to the block. The DP side doesn't crack.

I've never seen the exhaust manifold that bolts to the block crack.

Post pics!

 

I'd be questioning the condition of everything if that is cracked.

 

manifold shouldn't be cracked bolting to the block. As stated above, it's normal to have fisures on the opposite side.

 

I second that!. DP side manifold cracks are A-Typical. I've never seen that occur or mentioned on this forum. Heat cracks usually occur on the Turbo manifold to Engine Manifold connection as turbojeff stated. Although, I have a set of Twins with 28K miles in pristine condition

DP/manifold side crack is probably associated with a bad exhaust gasket leak that was never attended too(?).