Exhaust issue/moification on '80 AS

[brandon]

I knew Ron would chime in with his knowledge.  My only advice is to make sure the exhaust pipe he (the muffler shop guy) gets you is true stainless steel and not a ss plated pipe.  The plated pipe will rot out very soon.  Other than that, you got a good plan.

[56mulberry]

WEll in that case I think the best route would be to make a full stainless "H-pipe" that is attached to the manifold with a 8" piect of USCG exhaust rubber hose and has the crossover (in 2" "spuds" or spouts)  halfway between the manifolds and the bend at the floor--and the bend could be welded right onto the end then just run rubber/re-inforced all the way back (which is only actually about 4' +/-) and attach to thru-hull at rear.  I could then attach a 6-8" section of 3.5" plastic conduit (gray kind) along the stringer with hangers(the gray plastic kind) and stainless screws for a mount and run the flat part of exhhaust through it--since it rubber it should be abled to flex a little with boat movement and still be safely anchored there--maybe that is overkill but aseems tidy that way....

Added a couple rough sketches I did in Paint--make sense?  Anyone see any problems doing it this way?  Seems like it would be solid and durable as well as taking care of the crossover pipe issue all at once and relatively inexpensive since I can get the 2" and 3" stainless pipe from my muffler guy for free and have him weld it cheaply--I have the PVC for the sleeve/brackets laying here and the only real cost then would be about 8' (4 per side) of rubber /re-inforced marine grade exhuast hose to get from my "h-pipe" to the thru-hull exits out back.....

ANy problems foreseen here? thanks DOUG

[Mike Harry]

I like it. And I always like horsepower...... so when I pull the motor again Im gonna do the same thing (next winter). I got her built and running good, but never did anything about the way it looks. Wanna pull and paint it after the summer!

Thanks for all the info!!!

[brandon]

Sounds good.  I think the mfgs or maybe dealers used to wrap pieces of scrap carpet around them.  I don't know if is was for sound deadening, abraision resistance, or just to get rid of scraps of carpet.  It will look a lot cleaner the way you are suggesting.

[Joel]

Be sure to take lots of pics and post on here...  The cross-over pipe modification is something I'd like to do as well.   

[RonT]

To keep the system "legal" you need to double clamp each and every exhaust joint. I've never heard of anyone using pvc pipe, my concern would be the pipe collapsing when at full temperature under the hose clamps.

[RonT]

I knew I forgot something, the reason you see various things wrapped around the exhaust pipes under the center floors is for vibration, they tend to vibrate against the hull bottom unless suspended or insulated with something.

[56mulberry]

Yes--hence my using the PVC only as a short 12" "sleeve" or bracket to suspend the pipe off the floor against the stringer--the PVC would not be exposed to any more heat then the rubber exhaust produces externally to the touch---look at my diagrams again.  thanks DOUG