CMI exhaust
 

Does anyone know what year they had problems with them leaking? Did they stop leaking in 06?
I'd hate to spend large dollars on a boat and find out exhaust needs to be replaced.

Thanks Joe

Got a few spare hours? Do a search on CMI headers, this issue has been discussed in nausium.

Short answer is that you want the headers that the outer tubes are not directly welded to the flanges. You should see a 1/4" gap.

Had a nice and long discussion with Merc. Racing Friday PM. Had a great test run with the boat today and it's running great.
With all do respect Dave, but the earlier CMI headers were actually better made. (prior to CMI selling to the current parent co.) The 1/4" gap you referencing is actually one of the big problems. That "gap" is not cooled and it's the weak spot, many failures occur at the welds, but it's easier to manufacture. The the "old" style and the headers for the gov. have the outer tube welded directly to the flange. All areas have water cooling. Just an observation. :)

can you tell us what year that changed? I can't get a definate answer?
I agree if it is welded past the inner tube welded to flange, that short peice has to get a little hotter than the water cooled part, even if it is 1/4"

Thanks Joe

Are they swept back or etops

don't have them yet, but will be on 07 or 08 600 or 700 sci's

Well, now I'm confused. I read that "newer" style did not have the outer tubes directly to the flange. My 525 is a 2005 model.

I bought etops for my boat I've had luck with those

2005 IS NEWER style.
I'm working on a "No leak" header design. Getting close. If I have some time, I will find when CMI sold the Co. and some changes happened.
There is a way to "fix" (or at least help) that problem with the 1/4" gap. :)

Do tell, my 496 Sport Tubes has the gap.

Definitely share your fix to the 525 header problem!!!

the newer style does not,,,does not ,,,have the outer tube welder to the flange,,

I don't have a "fix", just some things that will help based on discussions with a lot of people, and companies.
I will elaborate on this later, but to reduce problems at the 1/4" gap, have a good welder weld some beads between the flange and the other tube. 6-8 at each gap/tube. Basically you will thicken the "inner" tube. Less movement, less cracks, more mass, better heat distribution.
This will add "mass" to that area and make it stiffer/stronger.
Just need to be careful don't burn through the tube.
In short the idea is to connect the other tube to the flange also.
Connect the top of the headers with a bar at top of the header. Like a tie rod. This will reduce vibrations and side to side movement. The weakest point is at the smallest area and thinnest. THE GAP.

That's what I thought. But Paradox said that CMI says that the 1/4" gap is the problem. Wouldn't that would mean that the "newer" sytle is prone to cracks too?

Well, it is what it is......I will just keep a real close eye on mine and hope for the best.

Dave
Read it again. Newer style is NOT WELDED TO FLANGE = 1/4" +- gap.
I did not referenced what CMI said. Others did. CMI did NOT SAY they have ANY problems.

OK, got it, newer = 1/4" gap.

The procedure you described includes adding material to the area of the gap. The GAP is the weak point

So, the newer style is prone to cracking issues too.

is this related mostly to the 525's

Mainly 525....more so with staggard 525's....but NOT limited too just those.

Noooo... Not limited.. Don't know where did you get this or why you even commenting when you don't know.
Many CMI headers have problems. 496's, 500's ,525's, 600, 700. and even others. 525's are one of the most sold. Thus, most referenced.

I thought this "gap" is what CMI called their "cool collar" design that was supposed to be the best thing since sliced bread in the world of water cooled marine tube headers ... rendering those designs without it inferior and obsolete? The direct welded tubes like the old E-Top style are better, now? Are the one's with the "gap" cracking predominantly interally or externally at that junction from one tube to two tubes? I guess I'm confused now. :confused:

Does anyone have 07 or 08- 525, 600's or 700's with header problems

Thanks Joe

Just replaced both sets of mine on 07 525's. All 4 of the old ones were leaking and one of those had been replaced previously.

Wow!! I thought problem went away in 05 - 06.
That's not right.

Thanks for reply

AS,
MAN that is just crazy!:angry-smiley-038: I'm assuming that you have talked with "Smarty" here on OSO about this.....
Good luck.
Dean

I think the Etops are the stronger of the two I run in rough water all the time had them on two boats.I run with my friends who have newer boats the swept headers on two of my friends boats have had problems one small one bad. But down here in FL we run them like we stole them. All the hard bouncing I think is what brakes them. Just my thoughts. I'm not a pro but know people who've work on race boats for a long time. I've been in the shops and seen a bad header trash alot of motors .

Sure have :grinser010:

The "Gap" as commonly referred to is what CMI call's their Cool Collar it is a patented design that they chose to switch to. You will find in the case of the 525,600 and 700 Merc engine header failures they have nearly nothing to do with flange failures but that of rotting out internally. As so many different posts have referred to.

We sell both the CMI GEN-X header http://www.keitheickert.com/p-14849-...0-engines.aspx

and the New Hardin Hurricane Lite as direct replacement headers for this application to reference two different styles. http://www.keitheickert.com/p-15770-...mi-flange.aspx

Is this thread heading to a Mod clean up also? The Merc CMI threads seem to go MIA, sucks to see so many members here getting stuck paying the bill for a bad parts.

LMAO. Ditto bud.... I don't want to get into a long CMI discussion, the last one I started got deleted.
The short version; Motor, drives, etc. 2007, rigged in 2008 on new Avanti hull in Spring, 2008, During rigging we noticed one header had pit holes on the lower distribution track. Replaced by Merc, under warranty. Boat, motor, drives are in, boat running great, 2008-2009. Checking routine compression late 2009; problems. ALL headers were leaking, including the new, replaced one. Engines had valve issues. Luckily nothing major. Engine uppers, (valves springs etc) redone. Headers shipped to CMI, CMI confirmed the leaks, fixed them (I Paid shipping, paid for polishing which was not done by CMI, etc.). After gezzillions of $'s boat back in good running order. Late 2010 routine check. Two headers are leaking again. Engines were riligiously flushed, headers drained, etc. Motor dino. AWSOME, 580HP, I got lucky again, no motor issues. Headers fixed, purchased new, boat running great.
CMI diplomatically told me to go fly a kite.
I went kite flying and came up with a conceptual design that will ELIMINATE ALL leaking header issues. Plans are in the works, will post on this soon, but I think I got the issues solved. :) Out of the box thinking, but it works, fab shopes are making proto type. Warranty: LIFE TIME. well ok not life time, but 10 yrs. is good enough, and even if your X wife puts a hack saw to it, it won't hurt the motors. Any interest? :evilb:

Picture of "the gap" thought it might help out. I'm a visual type of guy. :drink:

Got any other "gap" pictures you care to send out? :drink:

just bought an 09 with 600's whats the best way to test them and can it be done without removing them?

Lost two 525's to CMI headers on the last boat. Now my 2007 with 700's - I have replaced one header, repaired another and just pulled the last two due to leaking. What the ???? CMI needs to pick up my $21K in repairs etc.

You'r funny. CMI may pick up the phone, that's about it.

Misc.
Pic 1, "no gap", Pic no. 2; "gap" and rust due to leak.
Attachment 447984

Attachment 447985

With all the horror stories I've read about CMI failures, I'm absolutely amazed they are still in business!!! Who in their right mind would buy from this at this point? Even if they offered a decent/proven product, I still would not give them a dime of my money! :mad:

Guy's thanks for all the imput. Why would you go back to CMI, if your replacing why not go to another brand?
Just wondering

For those that had leaks, how did you know?

Was water leaking externally? Milky oil? Wet plugs?

What's the best way to monitor the situation?

EXACTLY, try SM or Stellings. Too bad KE's won't fit. Don't know if IMCO fit, if they do, that would be the route I would go!:drink:

My oil temp. went out of sight. Hot exhaust gas blowing in the water wouldn't let the oil cooler do its job. Same thing happened on a friend of mines 38TG who had to replace all 4 of his last year.

I've got one that needs a new home if anyone is looking for starboard side: http://www.offshoreonly.com/forums/s...rd-header.html

:grinser010: