Mercury 700sci 2009 model, manifolds
 

Hi guys,

my Cig 42x 2009 model, needs replacement of at least one header & tube. It has 219 hours, and is 5 years old already. Because I bought it just now, I am not aware how it was preserved as ehcaust system before so I am thinking, to avoid any internal links to change it complete for both engines.

I have seen that there are 3 choices :
1)Stainless marine
http://www.stainlessmarine.com/produ...c-replacement/
2) Custom Marine
http://www.custommarine.com/headerapps/genxheaders.php
3) OEM Mercury

Stainless marine is different to the others significantly since they use one big tube instead of a usual manifold with big curves for all 4 tubes.
Custom marine seems very close to OEM Mercury design, I am not aware if they are completely the same.
I use the boat only in salt water but will take extra good care of it (always fresh it afterwards and drain the exahust etc).

What do you suggest in terms of longetivity and performance?
Any idea of (total) cost for complete exhaust system for both engines? I imagine it is seriously painful..!

I would not use the Merc spec OEM as they are known to go cheaper on the build quality than the custom.
I have had both Stainless Marine and CMI over the years and like them both. That said, all my friends who have the 700's run CMI.

I'd go with Stainless Marine, I know they aren't as good looking and you loose a little bit of Bling. But I'd rather loose some Bling then a motor. Stainless Marine make just as good Horsepower. I have seen them candy coated in a variety of colors and I have also seen the manifolds polished. They look great to me and you will have piece of mind. There are about 100+ threads on CMI failures. Try to find one on stainless marine failures. Just saying

We just switched from CMI to Stainless Marine Gen 3 this year! Very happy with the quality and customer service!! Looking forward to not having to take headers off and pressure test them all the time.....

I have spoken with people that have used Stainless Marine for over 12 years in salt without any problems!! That was the final deciding factor for me!!

OEM Merc headers are made by CMI to Merc specs. They are actually lower quality than the CMI Gen X replacement headers.

If I remember correctly, you are in Europe and were asking about extended salt water use for long periods of time.
If that is the case, I would definitely go with Stainless Marine over CMI's.

I would imagine, you are looking around $10000 US for a complete exhaust system.

Thanks Guys. Indeed Griff i am in Europe and I do only salt use.

How often per year do you pressurize the exhausts? Every year once (?), or every X hours?

Do you lose power with Stainless marine?

I was pressure testing my CMI headers after every poker run. One was leaking and I had it welded up but was paranoid the others were right behind with leaks.

Gen 3 Stainless Marine system is supposed to make more power..

I would say it depends on how old the exhaust is. If used in salt and the exhaust is more than 3 years old, I'd say at least every year.
You will not lose any power with Stainless Marine's over the CMI's.

I switched over to Stainless Marine gen 3. While not as flashy no more headeraches.
No collector leaks, 02`s stay dry, easier header bolts to access, more bilge room, longer tails help reversion, etc etc ..all around win.


http://33outlaw.zenfolio.com/img/s12...92116456-3.jpg

Are yours the original headers? Do they have the cool Coller on them? (about 1/4" of space on the back side of the mounting flange where the weld for the tube starts vs right up against the back side of the flange).
There is a guy in the Cleveland area that is awesome at fixing them. Name is Bob Anspach. Does a bunch of them and never seen one crack again at least in the same spot. If they are corroded a lot he probably won't be able to do anything for you. It might only be one or two spots and can fix them. He can also check the ones that are ok and hit any spots that they usually fail in.its worth a shot.

I forgot your the guy over seas that just bought that on. That's a lot to ship all the way to Ohio for a 50/50 chance. Let me know if you are interested.

I still don't understand how those fit on your boat and not mine, it's pretty much the same setup....

Are you talking about the Gen 3 exhaust? They fit my gun and I have a very narrow engine centerline 35". I had to use their close application manifolds and clamps in the center. The regular stuff almost fit but the risers were touching, Jerry sent me the close app stuff and now I have around 1/2 of clearance in the center of the risers.

We are a CMI and Cigarette dealer. We have GEN X CMI's in stock. Call Lance for details at 573-873-2300 or [email protected] , we would be happy to help!

Yes, had the gen 3 and it wouldn't work for me when we put the new engines in. I think we are about the same centerline at 35". Sucks, but way beyond that point now. Everything is in, and I hope it's not coming out for a long time (already been in and out of the boat probably 3 times!!!)

Go with the Stainless Marine. I've never heard a single complaint about them other than aesthetics, and given where you are, I'd take reliability over pretty any day.

Custom Marine told me that the headers in my boat are all custom taller leaned headers specific to that build. All 4 are "straight back" style, the front are 3" taller style, and the inside header on each engine is leaned (front leaned in, back leaned out).

I believe I have to go to the same root, which is CMI reproducing the same staff as they did for Mercury. Otherwise we will have to change all tubes after mufflers I believe, OEM will not fit.
Have sent email to Stainless marine with photos of my engine bay as well, I wait to see what they say if it fits and then decide.

You are all right about the reliability staff, it probably will be a big blow if water leaks in the cylinders in quantity..

Stainless Marine. I was going to run them, but they didn't fit. Went with a similar design but one piece, KE Lightning manifolds. They are aluminum, and not as pretty as stainless tubular headers, but for the same reason as above, RELIABILITY. I was nervous about the leaks, and a few others have switched up here (even in fresh water) from headers to manifolds.

Also, it's not only the saltwater that makes them leak, the vibrations and movement/harsh environment with the hard hitting can fatigue and crack welds over time. Somethings gotta give.

Yes you will need new tail pipes with Stainless Marine. CMI (Custom Marine) only last around 5 years or so, think about that. next 2-3 years go by and its time to spend another 15-20K on exhaust. Tail Pipes can leak as well. CMI has become known as the worst marine exhaust made, their stuff just does not last. Do a search on here for leaking CMI headers, you will not like what you find...

To late now but he cuts 1/4" off the exhaust flange to make more room and lowers the riser mount to keep the tail pipe at the same height. You can order the close application manifolds or the regular. Also the close application riser clamps have 1 bolt instead of 2.

That`s good info, i have a set of the close manifolds but they hit my valve covers because the valve covers sit higher due to the spring oilers. So I had to get exhaust spacers.
Did not know about the one bolt riser clamp , that would be nice. Mine keep scratching the valve covers

A lot of those pipes, or headers are custom, not off the shelf headers and are specific to a certain boat. I had a ton of trouble with CMI's leaking in the past. On the last boat I had Phil at Lipship Performance install a set of Stainless Marine headers, actually the whole system. Phil's installed them on pretty much every Cigarette model so if you don't already have something set up yet maybe give him a call and see if he could answer your questions and maybe get something sent over to you. They don't look as cool as headers but I don't hear of them leaking and trashing engines either. Paying repair bills caused by leaky headers gets old fast.

Anyone ever dyno'd their setup before and after an exhaust change?

Switched from Gils to CMI's on a 525SC. No difference in performance.

I believe they were cut already, at least there was not much more we could do (no stock left to cut), in order to make them fit. Believe me, we tried everything, we even though about moving the engines apart because we had room with the driveshafts. In the end, it was more expensive to buy "new" manifolds. I think we even found out that one motor had been "tilted" away or rotated in order to make them fit on the old 454s. It was a crappy day when I got that phone call.

You must be tighter then 35" because I have a little under 1/2" of clearance between the risers now.

I cannot remember the exact measurement, but 35"+ comes to mind.

Off topic but what props are you running? I forget. I did the BAM calculator with what Gil told me he ran the boat at just testing, it was coming up around 10% of slip which I thought was a good number. I know the boat is underpropped now, I may pick up a pair of 32s before next season. Just curious what your baseline numbers are seeing as we have a pretty similar setup. I want to get an idea if I can push big diameter 32s just under the limiter.

I run 32's, it is 90mph at 5,000rpm never took it past that but I am around 3/4 throttle. Cruises 60-62 at 3500

^^ That's what I'm going to move up to, what diameter are they? So, if you can spin them to 5700rpm, you're right at 100mph in perfect conditions, pretty cool. So are you calculating about a 10% slip? That's about where I think I am.

8 years old on the Gen 3s. Before that I wore out 3 UPS trucks sending CMI s back to be fixed.

^^Do you use anything to coat the stainless/aluminum pieces after you polish?

No, it's a never ending labor. But not so bad, make a rum drink, put on cotton gloves, get two microfiber rags and the mothers polish, rub a little..... Sip a little..... Repeat ��

Get that boat down to Florida!

Ha, I most likely will at some point. Planning to have a gooseneck next year that would be capable of such trips. The aluminum bolt together is fine for local trips, probably would not want to tow it to Florida on that.

My Konrads run bravo props. So 15.5" diameter, when I run 31p props it blows out at 3000 rpm and makes it hard to get on plane. The 32 will hold to 4500 before blowing out when getting on plane. Takes a second to plane but runs well after its up. 31 was 5 blade hydromotive, 32 is 4 blade bravo. Probably not much help for you...

Do you still have that cnc file for the hatch bracket you made? I would like to have my cnc guy make one if you do?