Another reversion thread.
 

OK, so I finally got my LS motor in the boat and fired up today. Motor fired right up and sounds great. But I ran into a problem, you guessed it, reversion. Here are the specs

408ci LS2
cam: 242/250 621.5/613 112ls. Cam came from Bob Madera
Exhaust: Lightning Headers with extended collector

Everything is brand new on the engine and headers. The motor ran perfect on the dyno.

After firing it up and getting the idle set, I let the motor run and warm up. After it was good and warm, my buddy noticed a drip out of the 2nd to back header primary on the port side. Upon closer inspection, it was coming from between the head and header flange. I instantly killed the motor. We pulled the header and there was probably a teaspoon of water in the back two primaries. I then pulled the other side, and it was the same way. So I pulled the plugs and cranked the motor over to get any remaining water out, then fogged the cylinders. Checked the oil, and it was slightly milky, so it has been drained.

Here is a pic of how my headers are made showing the extended collector
http://s25.postimg.org/58pq3nubj/image.jpg

http://s25.postimg.org/fwth2i4an/image.jpg

When the header is installed that extension is only 1-2" away from the back of my exhaust tip where the flappers are. I just put in new flappers and was wondering if maybe the water is coming out and hitting the flapper and bouncing back into the collector? If it just reversion from the cam being a little to aggressive, my only options are having new dry headers made or taking the flappers out and extending the collector well into the tip, but then I risk the chance of having a wave hit the transom and swamping the exhaust.

Just looking for some input on whether it would be worth trying to take the flappers out and firing it up or not? I really don't want to hurt the motor by getting more water into it. Any help is greatly appreciated!!!

Are the rear two cylinders primaries both on the bottom of the collectors ?

Also, a water drip at the flange would tell me there is a gasket leak there...which can cause reversion in of itself.

Yes, the rear two cylinders are on the bottom of the collector. And I agree, the drip shows little exhaust leak, but I really don't think that's the cause of the water since the other side had the same problem but no drip. In all actuality, I'm happy there was a drip. If there wasn't, my buddy would have never seen it and I wouldn't have known there was a problem till it was too late.

Needs a dam on the bottom between dry and wet section.

Cmi and revolution marine does this. Eddie marine just started as an option. Lightning should too as some others have run into this too.

What do you mean by a dam? I've never heard of that. Thanks for the input!!!

Here's one in a basic exhaust manifold:

http://www.michiganmotorz.net/images...et/diagram.jpg

Gotcha. Thanks. That looks like something that would have to be put in the collector since it actually sticks out farther than where the water is introduced.

Yes, in collector, but no, it is before the water enters the exhaust stream. This way, when water is sucked back, it hits this instead.

Cup your hand halfway, tilt at a 45* angle, and you'll see what it will basically look like put into a header collector.

If you look at how my headers are built, the exhaust part of the collector is necked down to 3" and extended out past the end of the larger collector where the water is introduced. So the water actually enters the 4" exhaust hose that connects it to the tip before it ever comes in contact with the exhaust. So to put a dam in, it would have to go into the smaller exhaust part of the collector.

Yes, exactly..... In the 3" dry part. I would put it further back towards, but not right at, the primaries because if you out it towards end of collector, water from top of collector can and will fall back into dry part as it runs over and some is sucked back. CAll Lighting and see if they have ever done this. If not, they should. Like I said, some of the other exh companies have learned this and do it standard or optional..depending on the company.

Yeah, my first call Monday morning will be to Lightning. Thanks again!!!

I had Eddie Marine extend my tails..
They necked the extension pipe down some then added a flare help throw the water against the exhaust hose and to prevent it from running back up the pipe...


http://i130.photobucket.com/albums/p...pscvxbozph.jpg

Lightening very good company. My first set came from them in 1992. They've come a long way since then. With price also. I paid just over 1k a set back then. Regardless they will work with you and get your problem solved.

They were great to work with when I initially ordered these as well. He talked me into the extended collector to help fight reversion. I have no doubt he will be able to help me through this. I know I can weld the collector even longer if I have to, but then I will no longer have flappers to protect from a wave hitting the transom.

Thanks again for all the help and input guys!!

If you extend all the way through the transom, you could install some Shotgun muffler tips to prevent wave intrusion.

I think I have all but talked myself into just buying dry exhaust. I have a slight case of OCD so I know unless I go dry, I'll always be worried about it. Plus the thought of putting mufflers on exhaust that is wet makes me cringe, lol. If its to loud dry, then I'll look into a set of mufflers.

Well, there you go.

You solved your own issue.

I just pulled my EMIs number 6 had little gasket contact and appears perhaps exhaust leak caused some reversion. Next set of gaskets direct from EMI to better match manifold opening. I tested manifold and no leaks internal. Now I now cause of demise. Lucky no water to oil.

Yeah, I think so. I had just gotten home from the initial fire up when I made this thread, I wanted some other input. But after sleeping on it, I knew the only way I was going to feel good about it was to eliminate the chance of water getting in all together.

Thanks again for all the replies guys!!! It's great having a place to bounce ideas off of folks with a lot more knowledge than I have!!

This design is what is used a lot now in circle track racing....I think would be great in wet exhaust too, but with a few design changes.....

http://www.grumpysperformance.com/archamber.jpg

Talked to Lightning and even though it has already been stated in this thread, I can't say enough for the customer support I have gotten from them!! They have earned a customer for life. I'm going to ship him my headers today and he is going to dry them for me and hopefully have them back in a couple of weeks!!!

Scott, where would the water be introduced in a design like that?

Past / Just past #232 in that one. The one I have designed on paper , that I keep kicking around the idea of, is very similar to that but less 'bulbous' on the outer pipe. Exact same function though.

We'll see if I get around to it....but would almost wish an exhaust company would incorporate it into their collector / tail...would be better / easier for the consumer.

Edit in: 220 is the inlet side. 232 is the outlet side.

SB i am going to go dry until last 3-4" from tip and introduce the water about 3" behind that with a flare similar to Boatally Insane. since we are extending my risers and a good friend of mine is a top notch stainless/metal fabricator i may have him bulge the 4" slightly around the lower half of the 8" of new section we are adding (it will be water jacketed) and it already has 1 dam at the top bend in exhaust tube but was going to add a second at the new section we are adding on. what do you think? My cam specs are very similar but in a 434 sbc and idle at 950 RPM (112 lsa installed on a 108ICL).

I know this example is headers but my risers off manifolds are atleast this long judging by distance from back of block and make a very similar angle downward sweep. https://www.youtube.com/watch?v=iDiDeYCziU0
**not counting rubber exhaust hose**

and since exhaust will come down to 3-4 " from exit of tip and water will be introduced over extended exhaust pipe about 3-4 inches behind that i was thinking of incorporating this into the water jacketed exit of the water to still cool pipe but give it enough velocity for the molecules to somewhat stay together in a stream pattern till it exits?
https://www.youtube.com/watch?v=LAnkdbDFSeo

**only the external water ring**

COREY331
Where did you end up with this? Did reversion stop?
I am at the same spot today. Fixing to extend the inner tube way out, but dont want the noise.

Well, I sent the headers out to be made dry. Was told it would be a two week job, and its been a month and I'm pretty sure he didn't start on them till last week.

I made the decision to make them dry because I know that's the only way my OCD will allow me to not worry about reversion ever again. I know its going to be really loud, but I figure I can clamp on some nice looking mufflers in the future if it bothers me too much.

I am heading in the same direction except I have Eddie Marine alum manifolds and we are welding on 3" alum tube extensions about to the transom area. Maybe we can stop 3-4 inches short and it will stop the reversion but still let the water muffle it a little. If not, we will add more to the very end.
I also have mega condensation going on in the manifold. Maybe reversion is making it much worse, will see. Fix the reversion then check for condensation.

Let us know how it turns out.