I am currently fitting up an 1.9 AAZ engine with the manifolding off of a 1.6TD (JX vanagon parts).
Having enlarged and re-shaped the ports of the inlet manifold to match the head, I have now been surfacing the exhaust manifold ports (big thick ally plate with 80 or 120 grit paper stuck on with spray-tack).
I've noticed:-
The exhaust ports in the cylinder head are substantially smaller than the gaskets and the exh. manifold ports. If anything, this seems the wrong way around going from 1.9 into a 1.6 manifold!
Anyone else noticed this and is it deliberate, to expand the flow suddenly into the manifold perhaps?
Thanks for any observations on this, even though we're turbocharged, getting the gas in nicely and doing whatever it takes to get it out and drive the turbine best is still important, IMHO.
PS. Surfacing both the inlet and exhaust manifolds has been a bit of an eye opener, any leaks or misfits here and you could be throwing hard earned power away. In fact, one of the original exhaust ports (rear, No4) seemes to have been leaking at the gasket, to some extent. Both outer port flanges sit 0.025"~0.050" below the two inner ones, which I magine the gasket can handle .
Topic: Exhaust manifolds (Read 2881 times)
