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-   -   Internal exhaust flapper replacement question and advice please (https://www.offshoreonly.com/forums/do-yourself-boating-budget/322974-internal-exhaust-flapper-replacement-question-advice-please.html)

Diamond Dave 02-11-2015 07:43 PM

Hyfive, what scares me about the ones you have is that since Dana is no longer in business if I ever need replacement parts I am boned... :(


Originally Posted by HyFive578 (Post 4263534)
There is a rubber flap fastened to a steel hinge that lets the flapper open and close. That hinge bangs against the assembly its connected to. Any flapper thats inside the pipe is going to make some noise. Can't see how you can avoid it and still make something that will survive. They're advertised as "silent", I don't think thats true.

I don't think there is a "hinge" per say on these. There are metal "tabs" that hold the flap in between them if you look real close so no noise I would guess.




Originally Posted by dereknkathy (Post 4263596)
that is much like i was picturing. only the one i am designing in my head is the same size as the stainless tip and would sit just in front of the tip instead of sliding over and mounting on the tip. the one problem with the hardin design is it is a little bigger OD so the hose will have a hard time slipping over it. although i like that is is a salisbury style flaps shut instead of a lever style that doesn't seal as well, but is a little less restrictive...

I was wondering about fitting the hose over the Hardin one as well as well.... maybe that's why if you look at the link you can see below it "Customers who bought this item also bought:" and there is this: http://www.cpperformance.com/p-45-4-...aust-hose.aspx

US1 Fountain 02-11-2015 08:21 PM

May just be easier to replace them with what is there. Don't see these going bad that much. Mine are original and still good. (just checked).

I would however suggest you pull the diverters off and look at the condition of the y-pipe flappers. Those seem to go out and the flapper will fall down into the lower cavity of the y-pipe. Have seen pics of some that had done this and were left in long enough the steel bounced around enough to wear the y-pipe thru from the inside. Not a good thing to happen! If you raise your drive fully up, you can look inside the exhaust bellows and see the broken flapper ears laying inside the y-pipe, if you have the boot style bellows, vs the accordion style. Either way, can pretty much guarantee yours are broken/missing if never replaced

dereknkathy 02-11-2015 10:21 PM

i don't think it is wear. it is differential metal underwater corrosion rots the y-pipe. friend of mine dropped a socket down there fresh water boat. 2 years later it almost sank. another problem with add-on flappers in front of the tips; the farther north in the exhaust stream the hotter the stuff the flappers have to survive...there is something to be said for ugly black salisbury steaks hanging off the back of the pipes.

Diamond Dave 02-12-2015 12:34 PM


Originally Posted by US1 Fountain (Post 4263638)
May just be easier to replace them with what is there. Don't see these going bad that much. Mine are original and still good. (just checked).

I would however suggest you pull the diverters off and look at the condition of the y-pipe flappers. Those seem to go out and the flapper will fall down into the lower cavity of the y-pipe. Have seen pics of some that had done this and were left in long enough the steel bounced around enough to wear the y-pipe thru from the inside. Not a good thing to happen! If you raise your drive fully up, you can look inside the exhaust bellows and see the broken flapper ears laying inside the y-pipe, if you have the boot style bellows, vs the accordion style. Either way, can pretty much guarantee yours are broken/missing if never replaced

I was under the impression that they blow out all the time so maybe you are right and I should just replace them with these: http://www.cpperformance.com/p-12576...t-flapper.aspx

I didn't like the idea of leaving the existing "rods" in there anyways but it wouldn't have made any difference I'm sure... As long as the OE ones will last I don't mind replacing them with the same thing, but like I said earlier being a new owner I have no idea how long they should live.

More flappers!! When does it end! LOL! Well I'm pretty sure that since my downstream ones are cooked like they are that the Y pipe ones are as well like you said! Thanks for pointing that out I never knew there was even any in there!

Jfoster 02-12-2015 12:44 PM

1 Attachment(s)
[ATTACH=CONFIG]536936[/ATTACH]I went with Teague's rubber flappers there real nice.

Diamond Dave 02-12-2015 01:14 PM


Originally Posted by Jfoster (Post 4263882)
I went with Teague's rubber flappers there real nice.

You mean these?

http://teaguecustommarine.com/em0011...pper-assy.html

They are cheaper than the ones CP sells too which I like!

Jfoster 02-12-2015 01:35 PM

yea those are them. just added a pic I with them installed

Diamond Dave 02-12-2015 02:16 PM


Originally Posted by Jfoster (Post 4263909)
yea those are them. just added a pic I with them installed

Yes those do look nice, definitely beefier than the shred of one I have left lol!

Does anyone know if the exhaust needs removed such as in the picture (post #15) or can they be changed in the boat without removal?

US1 Fountain 02-12-2015 05:46 PM

Not sure those would work, at least on mine they won't. My tips are not perfectly square to the transom, so that welded on flange may not set flat to transom when the tips are connected inside. Might take a real close look.

Diamond Dave 02-12-2015 06:29 PM


Originally Posted by US1 Fountain (Post 4264032)
Not sure those would work, at least on mine they won't. My tips are not perfectly square to the transom, so that welded on flange may not set flat to transom when the tips are connected inside. Might take a real close look.

I think Jfoster just used the replacement flapper kit they sell in his original exhaust pipes (in that picture) which is what I would be doing as well....unless I destroy them getting the new flaps in lol!


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