4” Exhaust Material

[LuckyDog33]

I’m in the process of removing heads on my crusader 454 due to 1 stuck intake valve. When I removed the exhaust system from the riser/elbow, consisting of a combination of 4” marine wet exhaust hose, cast iron 90s, and a cast iron tee. I’m sure it will be fine, but if I’m doing the work, I want to replace with all new. MY question is should I go back with fiberglass instead of cast iron? My last boat had 5.7mpi’s and had fiberglass, not cast iron. What are the pros and cons of each? Thanks in advance!

 

[missnancy]

No rust to deal with.

 

[makomark]

lighter weight, too. We made custom parts when the engines were overhauled...

 

[LuckyDog33]

That’s what I figured. Just didn’t know why or if there was some odd reason they used cast iron…. Fiberglass it is

 

[390Express]

My 1996 390 Express has fiberglass 90's, they work great. I had to reef on them pretty hard to get them off, and never even heard the fiberglass make a crunching or collapsing sound. They're pretty sturdy. If you ever want to take this thing apart again, do yourself a favor and add a thin film of marine grease on the rubber 4" hose.

 

[Cokebuster]

That’s what I figured. Just didn’t know why or if there was some odd reason they used cast iron…. Fiberglass it is

I'm crossing that bridge now with my twin 454's. Any tips or issues since you made the switch to Fiberglass?

 

[makomark]

Keep the initial 24" of hose, from the elbow outlets straight if your can....and make sure the entire system 'slopes' downhill. AWAB style clamps work the best and don't overtighten them...if you can keep all of the hose sections straight, you don't need the wire reinforced hose...