CMI heads up !!! Caution

[mphatc]

A year ago I received my CMI's exhaust headers for my Corsican SBF application.
Because of other distractions and issues with their fitment I did not get my boat into the water until Labor Day w/e and only have 5 hours on the new set up.
I have experienced loose header bolts, poor gasket sealing surfaces, and the latest a water leak from a weld on the headers at the exhaust port. This leak was not external and or visible! I only discovered it when I had to remove the header to access something else. One exhaust port was very wet!!! VERY WET !!
Close inspection found that the weld quality on 3 of four joints where the water jacket is welded to the exhaust tube near the port had minor leakage. This is from to much penetration and poor weld quality, from the look of the inside of the exhaust pipes they were not filled with an inert gas or purged during the welding. A simple procedure and essential when welding tig welding SS tube!
Possibly this is a rare, maybe a quality control issue as CMI changed ownership last year to Mercury Marine, and my set took 10 months to get!
Had I not caught this now, certainly I would have been building another engine as my boat often sits unused during the summer for several weeks. I can imagine the water from one exhaust tube leaking into a cylinder with an open exhaust valve . .. :frown:
I'll be removing the other side now as well, and getting them rewelded and then I'll check all the weld joints on a Helium Mass Spectrometer to ensure that there will be no leaks. While I'm at it I'll build up the gasket sealing surfaces to match the ports . . .

Will this boat ever be done???

Mario L.

[kramsay1234]

Thats crap. Sorry for the headache. Good thing you caught it though.

[cutwater]

Sorry to hear this Mario. You do such a great job on your projects, as many people here do. Good thing you caught it now, and good luck getting it fixed!

[mphatc]

Thanks guys for the kind and nice words.

I now removed side two and have pictures, it had puddles of water in three exhaust tubes, fortunately they curve down lower than the exhaust port, so no actual water got into the engine as best I can tell.

After I have a nice big drink I'll post those :drunk:

Poodle, will that flux capacitor allow me to go back to the H&M and Volvo? If so I want it now!!!

Mario L.

[mattyboy]

Mario,
sorry to hear about your problem, i have heard some issues on the leaks in CMI's do a search on oso there are some threads that might be helpful
here's one

http://www.offshoreonly.com/forums/showthread.php?t=185910&highlight=cmi+leaking

[mphatc]

Holy Chit Matty!! Thank you!

That's a terrible thread for CMI .. . but certainly confirms all that I found.

Sadly the problem is easily avoided and would have cost them a few bottles of argon to avoid . .

sidebar fwiw . . SS tube when welded will crystalize when exposed to oxygen during the welding process, this can be avoided with a blanket gas or purge of argon, which is a heavy gas that settles and is inert.

leak detection is simple with pressurized helium and a leak detector that sniffs and reacts to helium or leak testing under vacuum.
I used to build cryogenic heat exchangers for research that used helium at high pressure. Helium is one of the smallest and lightest atoms and will leak through glass! We used to build SS piping systems that were helium leak proof . . and these baahhstaads can't make them water tight . .WTF???

Mario

[BUIZILLA]

for what CMI charges, there's really no excuse not to get the gassing part right... when I was a jet mechanic we had a welder that could probably weld tin foil together using argon, guy was phenominal... he did all the nacelle repairs and his work was pure artform when he was done.. to this day I've never seen anybody come close to him..

[mphatc]

here's what I found on side two

images shown first are as removed from the engine, along with the CMI adator flange with the rust . . last images are when I poured the water out of the manifolds on the garage floor . .

Mario

[mphatc]

More pictures

[MOP]

Sorry to hear about the problem, I went to Boston to check on a set of CMI's they too had cracked inter tubes, the guy had them re welded looked like chicken poop so they stayed in Boston.

[Shanghied Again]

Matty. I feel for you CMI better step up to the plate we have seen over 10 failures this year alone on 525s and 700s the welds are complete crap they are leaking and so far two Customers lost engines Mike Intel with his 38ZR 700s lost an engine last year and lost another this year all from leaking headers. They charge a hell of a lot for there product and they are not delivering.

[mphatc]

Frank,

I think you meant me, Mario . . see my post on OSO in the thread referenced by Matty above . .

This game isn't over!

Mario

[mattyboy]

Mario,
I hope this all works out for you, I did hear some things about certain CMI's that need more sealant or double gaskets to stop leaking, but not sure that applies to your problem or the ones that Frank mentioned.

[BigGrizzly]

I can feel your pain. My CMI. on my boats were made before the merc buyout. I have had no issues at all. I do remember when I was up there getting mine made for the Criterion-Merc lost the spec. for the Merctrans and silent choice there was a discussion and heated one between Merc and CMI on the price of the COOL collar. My guess is that the PCD got involved (Product Cheapening Department). When they showed me through the plant I saw the pressure testing and Magniflux departments, that every pipe went through. I also saw the pride that went into the pipes that the employees put into the pipes. My guess is Merc put speed ahead of quality, which is to say that not every pipe is checked anymore. Mario I also noticed the welds on your pipes are not as nice as the ones on my sets. The only thing that I am glade about is that you caught it in time.

[Shanghied Again]

Sorry Mario.. Thats what I get for posting when My Brain isn't working