4.3 V6 conversion from RWC to FWC - riser/manifold plate still needed?

Hi,

I've converted my engine from RWC to FWC with a San Juan kit. The original RWC had water routed to the bottom of the exhaust manifolds and to the risers. The FWC kit has the water routed to the bottom of the exhaust manifold only, the riser inlets are plugged by design of the kit.

My question is about the stainless plate between the riser and manifold, it defintely plays a role in the cooling, is it still needed if the the water is only coming in from the bottom of the manifold?

Thanks in advance,
A.V.

Re: 4.3 V6 conversion from RWC to FWC - riser/manifold plate still needed?

You have installed what's referred to as a Half System meaning Engine only.
The Volvo Penta AQ series manifolds were never intended to be closed system cooled. The ports are too small.
You have risers with ports in them. Probably Sierra or HGE.
The ss block off plates must be removed so that sea water can leave the manifolds and exit through the risers. That plate is not a block off btw.
Another option [if you did have a block off] would be to feed the manifolds as you are, and exit the rear of the manifolds and feed the risers.

If you notice a temperature difference between manifolds, check that splitter fitting to see if it's diverting sea water equally.

Keep an eye on the heat exchanger so that rust scale doesn't build up around the tube bundle and cause overheating.

Re: 4.3 V6 conversion from RWC to FWC - riser/manifold plate still needed?

Yes, you are correct it's a half cooling system. The reason I'm concerned is that the FWC kit never mentioned removing the plate and all the diagrams I've seen don't mention removing it.