Water jacketed pipes??

[bverd]

Okay, do I need water jacketed pipes all the way out the transom. On the old motor I had the big Rubber hose that came off the risors, obviously not water jacketed.

I am curious what the pros and cons are of having just polished pipes going from the risors out the transom or water jacketed ones.

--Brad

[MOP]

Hi quick question, did your hoses burn out? If so more than likely the risers need either cleaning or replacing. Even in fresh water they will eventualy give you trouble with rust deposits building up in the water outlets that cool the out going exhaust.

Phil / Long Island

[bverd]

No, no... nothing like that. I need to replace the "rubber hoses" because of the new angle of things with the new headers and motor, the old "rubber ones" just aren't going to work.

But the hoses weren't "water jacketed" so I don't think I will have a problem with a non-water jacketed pipes. That is my initial thought. I am eagerly waiting for others. --Brad

[CDMA]

The length of the pipes necessary depends on the cam you are running. If you are running a radical cam with short risers then you will have reversion, or the sucking of water back through the exhaust valave. If you are running a stock cam pipes out the transom are not necessary. But they do look cool....


Chris

[GEOO]

Brad,
Chris is correct.
Your exhaust manifolds dump the water into the exhaust right at the end of the elbow.
Two things: First the exhaust needs to be cooled. By water mixing with the exhaust or water outside the exhaust, ie. water jacketed pipe.
Second, If you have a larger cam you run the risk or reversion. Larger cams have the intake and exhaust valve open at the same time and can form a vacuum in the exhaust and suck water up the exhaust into your engine.
If you are changing engine with a larger cam you may need to change exhaust manifolds and pipes. My pipes mixed the water into the exhaust two inches from the transom. This worked fine with a hot cam, but with my new motor with a radical cam water was being sucked up the pipes and I needed to go with completly dry exhaust.
Reversion (water being sucked up the exhaust) can be a mild case; when your valves get salt and rust on the back side too a bad case when your oil pan fills up with water. Reversion happens at slow idle. The faster the idle the less reversion.
The best way to check is to idle your engine, then pull off the rubber hose and see if water is in the manifold. Honest I'm trying to make sense here!!!GEOO

[bverd]

Okay... Here is what I am thinking. What you see in PVC in the picture be just polished 4" stainless pipes (not water jacketed) replacing the original 4" rubber hoses. This is a new motor, yes, but not radical by any means with Stainless marine exhaust. This all started because I didn't want to move or recut any holes in the transom so I am looking into options.
http://www.verd.com/photos/donzi/p0003223.jpg

[Greg]

There was a post a while back where BROWNIE stated the maximum cam shaft lift and duration you can use and still maintain the exhaust system that you have. I would check with Stainless Marine about that.

[GEOO]

Brad, Have Stainless Marine make you a new Tail pipe. It would go from your manifold to the transom, (the elbow would be a part of the new pipe, custom to fit your transom.) At the same time you could have them dump the water into the exhaust farther back for safety. GEOO

[bverd]

Geoo... that is a great idea. I will contact them and send them my template and see what they can do. What are your thoughts in the mean time if I put in a custom cut set of pipes as you see it in the picture? --Brad

[RickR]

Brad
If the funds allow a custom riser is the way to go.
Next best would be a custom made tail pipe.
A less expensive way would be to use two of Stainless Marine's angle pipes (45s?) (on each side) with exhaust hose.
Beware; the "flexible type exhaust" hose does not bend much. I have not used the "corrigated type" but it should bend more.

Engine looks good! :D

[Scott Pearson]

I would leave the PVC there and just wrap it with FunFur....Red if you can get it :D


(NJ)Scott

[bverd]

Scott,

Do you think I could just cut up my jacket and use it? Remember I am on a budget here, or do you think "Nino" can skin me something? --Brad

[Dr. Dan]

Fun Fur? And a Skining Nino? Sounds like a punk band, I'd mold some out the left over silly string Pearson used to decorate his "Air Scoop!" ... :D Wow! I posted before your pic loaded, what are you guys? Somebody Stop Me!... Great Outfits, I'm afraid LIz might want one, hope she doesn't see Amys'.
;)

[GEOO]

Brownie can make anything you want. From the manifold to the transom, including the elbow. I gave him three or four measurements, ie. engine height, transom hole height etc.. The pipes would be one agle from the elbow top to the transom. I think there are some pics of my
GEOO

[bverd]

Geoo & Madpoodle,
Thanks for the advice... not sure which way I am going to go yet. I know I am probably going to get the pipe (no-water jackets) welded next week. No cost to me, so why not. I would like to use those until I can get some custom ones from Stainless or the like.

I will have to watch for the reversion. Do you think I am that much at risk with the drop of the elbow from the risor to the transom? --Brad

[RickR]

Hey madpoodle
Are you battening down the hatches? I am headed south Sunday, could you move Michelle out of the way for me :rolleyes:

[Scott Pearson]

You guys are weird....


(NJ)Scott

[BERTRAM BOY]

Fun Fur?.....What, no genuine woodchuck fur?
And how about some pink flamingo's?
BERTRAM BOY :D :D :D

[clayman]

Hey Guys,
all this talk about exhaust is my question for the day. I am still shaking down my new (for me) 86 Donzi . When I bought it the kid said he thought it needed new manifolds, because it was over heating. Well, I put the rubber hoses for the exhaust back together and ran the boat. it ran pretty good. no overheating. That turned out to be a faulty temp sender. so after about 10-15 times out on the lake, it quit on me yesterday and I was towed in. I fussed with it for a while and discovered the starboard side rear spark plug wire was off. I little bit excited about the possiblity of more power and speed, I checked the plug, hooked it up and the engine fired right up. It sounded better than ever. I took it for a ride, and boy what a difference. BUt, within 2 mins, I smelled burning rubber, and saw lots of smoke. I made it back to the dock, but the entire starboard side exhaust burnt itself to death. it blew holes in all three pieces. Is this a plugged riser, or manifold not getting the water to cool it? IF I need a replacment, are the Emi thunder, or stainless marine headers worth the $1000? Also, the s-pipe system form eddie marine is listed at $1200, that seems like alot for a couple pipes? how much are the custom systems? Anyway, any advise is appreciated,
James

[BigGrizzly]

Let me jump on this one. The only things that are as bad as the old log type manifolds are the stock manifolds on a merc. I have never heard of someone who didn't bennifit from a GOOD set of Aftermarket ones. I have two Oreferences. ! CMI and the other is Stainles Marine.

Randy

[Tom Davis]

One thing you guys have to keep in mind when you attach the "Vibration Isolated" motor (via rubber motor mounts) to the transom via the exhaust system without using rubber hose, the vibration from the motor has no where to go. Depending on how much engine vibration you have this could cause problems. Thats why on some race boats that run solid exhaust systems, they run straight out through the hull through an oversized hole or slot (also so they can lift the motors out with the exhaust system intact). Just a thought...

[Ed Donnelly]

I have a Stainless Marine Gen 111 Where the 4" exhaust goes through the transom, there is an oversized stainless steel beauty ring with a rubber seal. It allows for the vibration

[RP21]

Brad,
I have the same set up as your pvc, but in Stainless. Its in a 21 with a blown sbc and I have not had any problems. The flappers in the tips were changed to stainless and I used rubber hose(4") with double hose clamps to connect. I changed the tips to 4" so its all 4" from the risers out the transom.
Hope this helps Rob.

[bverd]

RP21... can you share pics with me of you setup. You can email them to me at brad@verd.com

Thanks --Brad

[Last Tango]

Just installed EMI Thunder polished exhaust on my MX6.2EFI. I'll let you know after Palatka what I think of the new system. Uses rubber hoses to connect with the stock Corsa tips (with baffles). Looks totally awesome, we'll see if it is.
Mark :cool:

[Scott Pearson]

Brad,
Just leave the PVC! Paint it a nice silver...And just install some old coffee can lids as flappers :D :D .


(NJ)Scott :D