D16A and D16Y Exhaust Manifolds the same? [Archive]

mrnivlek

24-06-2008, 02:45 PM

Hey,
I asked a few people today about the exhaust manifolds on the D16A8 (DOHC) and the D16Y1/4/8 (SOHC) can be interchanged with the same fitment without modifications between the two.
Reason being is that i'm one step away from purchasing a cast iron turbo manifold made for the D16Y SOHC motors and I've got the D16A.
I've been given no they won't fit or maybe it will fit, but no positive answers.
Can someone give me a positive final conclusion?

Thanks. :)

Munted

30-06-2008, 12:41 PM

According to http://dohc_zc.tripod.com/main.html

"The scoop on the headers, is that while the bolt pattern for the Civic SOHC engines and the ZC engines are identical, the port pattern is not. The ZC engine has the ports shifted almost 3 mm (appx 1/8"). In real terms, this means that when you use the SOHC header, the ports do not align properly. The exiting exhaust gases literally run into one edge of the misaligned header flange. You can see this by holding the steel exhaust gasket from the ZC engine up to the DC header.

The easiest and best solution is to use the ZC gasket as a template and mark the misalignment. Using an air grinder, with a small stone "port" the header to match the ZC port configuration. While you're at it clean up the entry point of the header a little so that the whole port on the header is slightly larger than the ZC port. It is an old, but proven trick that the larger header port decreases the chance of exhaust gas reversing flow and re-entering the still open exhaust valves. It is better to have the port larger than to have them matched identical. Do not under any circumstances grind the port on the head to match the header though. This gives poor results."

I can't vouch for the site's correctness although I have read similar things elsewhere, let us know how you go.