exhaust manifolds and risers

[vscgraphics]

Are there any other options other the th stock manifolds and risers.... that weigh a ton? What about headers, can they be used..or will they get too hot


Engine 1986 mercruiser 5.7 with alpha 1. 22" century

Thanks

 

[Brentathon]

Re: exhaust manifolds and risers

Exhaust manifolds and risers (aka elbows) need to have coolant jackets, to cool the exhaust before it proceed through the rest of the exhaust system.
How would headers allow for this?

 

[sea flower]

Re: exhaust manifolds and risers

Gotta keep 'em cool..... Find a diagram for you boat motor. They explain why better than i can. Yea they are heavy, They're made of cast iron. The better ones have a ceramic liner in them.

 

[redjmp]

Re: exhaust manifolds and risers

You can get after market aluminum manifolds. I just saw one at the merc dealer who says they are cheaper than the stock merc ones.

 

[wire2]

Re: exhaust manifolds and risers

Are there any other options other the th stock manifolds and risers.... that weigh a ton? What about headers, can they be used..or will they get too hot

Thanks

An I/O exhaust MUST be cooled or you'll have a fire.

The headers you see on a typical jet boat (open engine) are cooled by spraying water from a nozzle in all 8 pipes just outside the head connection. Unfortunately, it turns to steam, which expands and adds back pressure.

The other way is to make the headers double walled ss, to allow for a water jacket. They're hard to find, and pricey, so I made my own, with thru hull cut-outs.

 

[vscgraphics]

Re: exhaust manifolds and risers

Thats what I am talking about!