Exhaust Headers / 525 Mercury Racing Engines
12-29-2010 | 06:05 PM
#121
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Joined: Apr 2004
Posts: 151
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From: Gallatin Tennessee
CMI on Illmors
The quality on the cmi headers for the Illmors Suck to.
32b skater with illmors first one. Had blown motor when buddy bought it(because of leaky collector).
Now has one fresh Proline built motor trashed because of leaking header. He is planning to have new collectors built for all 4 of them. I say the way the exhaust bolts up to the collector on his boat is stressing it some to. It needs more support in that area on his exhaust.
Considering he loves speed and rough water.
I would test them every year illmors and others.
EJ.
32b skater with illmors first one. Had blown motor when buddy bought it(because of leaky collector).
Now has one fresh Proline built motor trashed because of leaking header. He is planning to have new collectors built for all 4 of them. I say the way the exhaust bolts up to the collector on his boat is stressing it some to. It needs more support in that area on his exhaust.
Considering he loves speed and rough water.
I would test them every year illmors and others.
EJ.
12-29-2010 | 07:29 PM
#122
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
Don't say I didn't tell people so a long time ago. 
Also, anyone who buys the whole Mercury not standing by their warranty because it's not their product and CMI saying Merc called for lower quality build it just fooling themselves. Come on folks, that's not how business works. I'm just tired or reading about all these issues. A stainless tubular header system by nature is prone to having leaks over time. It's physics. Some don't like to hear that but it's the way I see it from seeing and experiencing it over the years. Sorry in advance for offending anyone.
Also, anyone who buys the whole Mercury not standing by their warranty because it's not their product and CMI saying Merc called for lower quality build it just fooling themselves. Come on folks, that's not how business works. I'm just tired or reading about all these issues. A stainless tubular header system by nature is prone to having leaks over time. It's physics. Some don't like to hear that but it's the way I see it from seeing and experiencing it over the years. Sorry in advance for offending anyone.
12-29-2010 | 08:17 PM
#124
Platinum Member
Joined: Apr 2005
Posts: 2,150
Likes: 15
From: Northport N.Y.
I will pm u the torch # its a weld craft Very small.
12-29-2010 | 09:56 PM
#125
Registered
Joined: Feb 2005
Posts: 217
Likes: 2
From: FL
I have the same volume and pressure coming out the exhaust as I did before the drains were installed and have had NO temperature increase in the exhaust or pipes. I pull the boat after each run or at max. after a weekend and the motors get a thorough fresh water flush.
The picture below shows no significant water coming out the tubes, plenty of water out the tailpipes, and no steam.
The idea of leaving water sitting in the pipes to me makes no sense if you can get it out. Besides the corrosion factor, let's say you do have a weld failure or crack, if there is no water sitting in the tubes, there is no water to drain back into the cylinders.
Most damage occurs from the motors sitting for awhile, the water slowly seeping into a port. Go to start it up and Boom!
The only drawback I have found is you do get little stains from the water dribbling down the transom. Nothing a little Spray-Nine can't fix.
The picture below shows no significant water coming out the tubes, plenty of water out the tailpipes, and no steam.
The idea of leaving water sitting in the pipes to me makes no sense if you can get it out. Besides the corrosion factor, let's say you do have a weld failure or crack, if there is no water sitting in the tubes, there is no water to drain back into the cylinders.
Most damage occurs from the motors sitting for awhile, the water slowly seeping into a port. Go to start it up and Boom!
The only drawback I have found is you do get little stains from the water dribbling down the transom. Nothing a little Spray-Nine can't fix.
12-30-2010 | 09:12 AM
#126
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
It's not a fix for the problem of a cracked/leaky header but it can limit the damage done by having the water sit inside the pipe/engine. Having a drain tube with cold water spraying on a hot exhaust valve will not save it.
Headers should still be checked on a regular basis. Once headers are 2-3 years old (maybe longer in fresh water) I recommend checking them every winter as a precautionary measure. Also, use some heat when checking the welds... I have seen headers hold pressure perfectly until you put a little heat in it and they begin to seep water.
12-30-2010 | 05:34 PM
#127
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Joined: Jan 2009
Posts: 69
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12-31-2010 | 07:12 AM
#128
Charter Member
Joined: Nov 2000
Posts: 7,213
Likes: 395
From: Merritt Is. Fl. USA
I hear ya, but the cabin was way too small for us also. Plus, I'm seriously thinking about re powering our Nordic with a HP500's that will be tweaked up a little bit and I'll will be running new KE's headers, and I know that they will last forever, and out perform the CMI's. The last set I had lasted for 7+ years running in saltwater.
Happy New Year everyone.
Dean
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Last edited by Dean Ferry; 12-31-2010 at 07:25 AM.
12-31-2010 | 11:34 AM
#129
Gold Member
Joined: Jun 2005
Posts: 441
Likes: 1
From: Canton,Michigan
Hey Guys,
I had all kinds of header problems on my 525 boat. Moved up to 600 SCI's different boat. Headers look the same but no problems so far.
Are 600 headers made the same as the 525's?
Thanks, Mark
I had all kinds of header problems on my 525 boat. Moved up to 600 SCI's different boat. Headers look the same but no problems so far.
Are 600 headers made the same as the 525's?
Thanks, Mark
12-31-2010 | 11:56 AM
#130
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Joined: Mar 2010
Posts: 30
Likes: 0
From: Long Island, NY
