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Dana exhaust reversion?

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Old 04-13-2011, 10:39 PM
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Default Dana exhaust reversion?

Has anyone experienced water reversion problems with the Dana Marine Flow Torque exhaust?

Iím having this problem with my mercruiser 454 magnum after they were installed.

Any suggestions?
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Old 04-14-2011, 12:17 PM
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Wink Devil' in the Details Lets have some Details?

If your engine is a stock MPI engine, reversion in the exhaust with any exhaust upgrade should be a non-happening item. How have you seen reversion issues and what is telling you that reversion is occuring? How is your full exhaust system configured from engine to tips?? I would like to see and hear about your use, camshaft size and type, exhaust system routing and plumbing as I suspect that something else is causing water to back up in the exhaust , not the header manifolds from Dana. Dana has sold I am sure hundreds of these header manifolds with a lot used on Merc EFI and MPI big blocks and you do not hear of them reverting water from the header itself in an engine application such as this appears to be. . Lets see if we can find your problem?

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Old 04-14-2011, 08:31 PM
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Taint so. If you have the short risers, I would expect reversion.
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Old 04-14-2011, 08:37 PM
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Originally Posted by BROWNIE View Post
Taint so. If you have the short risers, I would expect reversion.

Hi Brownie. How goes it?

Craig
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Old 04-15-2011, 12:55 AM
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I know of 4 other users who have contacted me to ask the same thing.

Unfortunately, there does seem to be something to this but I never figured it out. I even went to Dana and had them add quite a bit of length to my risers (elbows).

It did not help but did not make it worse either. The moisture makes its way between the manifold and riser right where the gaskets are. I monitored my situation and was able to rest knowing that the water does not go down into the manifold much but does like to suspend where the two pieces meet and in the bend of the riser itself.

It's happened on several engines with different setups than what I have as well. We've all pressure tested the parts separately etc but mine are not leaking.

Mixing water and exhaust gas is a weird thing. Most people really would be surprised to see what goes on and how it works. I had a chance to watch it once through a make-shift transparent exhaust setup on a stock engine. Even with a mild, stock cam the engine acted as a vacuum when coming off the throttle suddenly like you do when running in rough water.

For some, the setup is making their issue worse. For others, it's par for the course. Either way, that exhaust kit does like to stay wet on a variety of applications.

FYI - That's 5 guys (including me) with 5 different engines and 5 of them have water coming out of the gasket after it soaks it.

That does NOT mean the kit is junk. There are far too many variables for me to be sure what causes it and I believe that kit was made for a stock engine so installing it on a modified engine will only aggravate the problem. Just keep an eye on it and run your engine as often as possible. You should do that anyway.

Best thing you can do is dry fire the engine(s) 2 or 3 times when you're all done playing so you don't leave any moisture near the valves and seats.

Last edited by SDFever; 04-15-2011 at 12:57 AM.
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Old 04-15-2011, 07:20 AM
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[QUOTE=SDFever;3377284 Best thing you can do is dry fire the engine(s) 2 or 3 times when you're all done playing so you don't leave any moisture near the valves and seats.[/QUOTE]

How do you do that and not burn the raw water pump impeller?
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Old 04-15-2011, 10:44 AM
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How do you do that and not burn the raw water pump impeller?
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You just do one second fires. You don't let it sit there and run. It runs dry a lot longer than that when the boat has been on a trailer you you fire it on the hose for repairs and testing...

One full second doesn't create any friction. I've done it for a long time. No pump problems. As soon as you hear it hit just bump the key.

I got the idea from Westcoast. It's a great way to help insure you don't have water sitting somewhere that it shouldn't.

Really a good idea for those who have to winterize.
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Old 04-15-2011, 11:33 AM
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Wink Exhaust moisture versus Reversion?

I agree on some of the items brought up by SD Fever here and I can also say that we must carefully qualify and quantify the description "reversion". When you have a high performance engine (one with a moderate size camshaft) on a normally aspirated engine or a boosted engine at lower rpms there is camshaft overlap. This overlap with both an intake and exhaust open at the same time for a few degrees of engine rotation you will have exhaust gases traveling back into the engine. and in a reverse direction in the exhaust path. In any marine wet exhaust system where water enters the exhaust manifolds or tips somewhere past the riser elbow bend you will have water vapor and mist in the exhaust path where its mixing with the exhaust gases in the exhaust. during the overlap period this vapor will kinda move back and forth in the exhaust manifold, usually close to the riser area and it will generally be blown out the exhaust and evaporated somewhat by exhaust heat. this is why if you where to look into a view port inside the exhaust system at the riser you would see this vapor and water particle mix in the gas stream. Usually this moisture does not get pulled in any larger quantities into the actual cylinders and valve areas but precipitates out and burns off before it accumulates in the valve and cylinder area. "Reversion" is generally meant to describe the condition when actual water from the exhaust is being drawn back into the engine in large quantities where the exhaust heat and pressures cannot keep it in the exhaust system and forced out the tips or exits. With larger duration camshafts in most BBC engines the size of the overlap can get to big and the water in the exhaust is traveling much farther and longer back into the engine where "reversion" can really occur.
As for the Dana exhaust, I cannot speak to all users and their individual issues with this water or moisture in the exhaust but in some cases I am sure the particular engine build, ie: cam duration size, items like switchable exhaust, tip length,exhaust pipe routing and exhaust drop measurements and such are probably creating some of the issues that some are experiencing and not necessarily the Dana header.
I will say that when we install the Dana risers on our Dana installs we seal the connection joint between the riser and the base manifold at the four runner passages to make a complete four tube seal between the runners and make sure the exhaust pulses only work in that individual passage and do not pull on the three others in the manifold.
I would like to see some more input from the thread starter here "TopChoice" who appears a a new poster here on OSO.

Best Regards,
Ray @ Raylar
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Old 04-15-2011, 03:17 PM
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Hi guys,

Thanks for your responses thus far.

Raylar I really appreciate your interest in this matter and eagerness to help.

I am sorry for not responding, but have decided it best to hold off. Without getting into great detail, I can say this matter is being addressed by the manufacture in a positive way.

Thank you.
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Old 01-20-2015, 11:18 AM
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Does anyone have any information on anything in addition to that described previously herein as to what can be done to improve/correct the reversion issue with the Dana EX2000 exhaust manifolds? I have exactly what SDFever described going on with mine.
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