228 mercruiser through hull exhaust on old thunder craft

[The nut]

Hey guys
So my brothers got a older thundercraft with the 228 mercruiser
Thinking of mb installing through hull exhaust
Has anybody done this on this engine?
Or a similar boat?
Thinking prob put tips through hull a good shot above waterline
But then would still like to b able to switch it to through prop
If anybody has pictures would b great
Thanks

 

[Scott Danforth]

if you want a captains call exhaust or similar switching exhaust. break out your wallet. OEM pricing is about $2500 for the diverters, actuators, mufflers, tips, etc. aftermarket pricing is about $5k.

here is one of the more prominent manufacturers. https://corsamarine.com/pages/performance-exhaust-types

Other than noise, there is nothing to be gained on the 5 liter 228

there are some surplus sites that have partial kits for about $1500

does the old thundercraft still have the log manifolds, or have they been updated to the newer manifolds?

 

[The nut]

Hey sorry for dum question but I don’t have a whole lot of experience with inboards yet

What’s difference between log manifolds and the newer ones?

 

[Scott Danforth]

log manifold.

center rise manifold.

 

[The nut]

Ok it’s the log manifold

 

[Scott Danforth]

most of the diverters on the market today will require you to upgrade the exhaust manifolds prior to using their kit.

as stated, that is a lot of money to spend on making the motor loud. there is no performance gains on your 5 liter.

 

[The nut]

Right yup ok

Would it not b possible to do a bit more of a redneck job?
Like Would it work to find a universal diverter of some sort to attach to circled part there on pic and just some pipes straight out the back?

 

[alldodge]

Right yup ok

Would it not b possible to do a bit more of a redneck job?
Like Would it work to find a universal diverter of some sort to attach to circled part there on pic and just some pipes straight out the back?

Anything is possible but I seriously doubt it will work.
There is a rubber boot that connects the elbow with the Y pipe and just not enough room

 

[The nut]

Ok yup
That is where I would go off of tho to go through hull?

Does that pipe exhaust water as well?
Or just engine exhaust?

Just wondering cause for winterizing I know there’s a plug on bottom of manifold there to drain water?

Sorrry again for dum questions!
Still new to it all

 

[alldodge]

No dumb questions yet

Yes, man's need to be drained for winter.

Yes, exhaust also has water coming out

 

[The nut]

Oh ok so if I would have exhaust above water it would look kinda dumb cause water peeing out the whole time?
Or is there a way to have just engine exhaust coming out?

 

[alldodge]

Every marine motor running prior and today with thru prop or thru hull all have water coming out with the exhaust (2hp to 2000hp). This is how and why the exhaust stays cool and doesn't burn the hull up

 

[The nut]

Oh ok makes sense!
So if I would get around to experimenting then mb it would b cooler to have pipes come out 1/2 inch below water line?

 

[alldodge]

Oh ok makes sense!
So if I would get around to experimenting then mb it would b cooler to have pipes come out 1/2 inch below water line?

I would strongly suggest not doing that.

While the exhaust would come out of the water when boat is on plane, coming off plane the water wave would hit the stern and could force water up and into the man's and can hydro lock the motor

You should get elbows higher to try and stop this

 

[alldodge]

Note, thru hull exhaust doesn't look like it's peeing, it's puffs of exhaust with burst of water

 

[The nut]

Ok..
So a boat like this would have a bit of water coming out?

So if I find a diverter then elbow up from man’s and then through hull a good piece above waterline would b safest?

 

[alldodge]

yes

 

[The nut]

OK thanks man!
See what and if we do anything