525EFI Header Failures - CMI vs Hardin - All failing
 

I went to change the oil on my 525's and guess what... water in the oil again. I thought I was done with the 5 years ago when I bit the bullet and spend over $10k to buy two new sets of Hardin Marine headers. They at the time claimed they were so much better than the CMI's which were failing. We'll interesting where we find ourselves now. After 2 years, one failed and they repaired it under warranty. I pressure tested both of the problem engine and one had a few small leaks on the welds. I sent it back to Hardin for repair and received a call from them today. The headers are rotted out and need to be replaced. 5 years old and they are junk? I am extremely disappointed in not only the failure but their complete lack of customer service. The representative claims their headers only have a 2-5 year life span in salt water. FYI to anyone thinking about buying them. So now I am going to try and have them repaired locally. Anyone put cast manifolds on their 525's????

Stainless marine. They even will send te jig to re drill the heads for the bolts. My next boat will most certainly end up with stainless marine. Don't read anywhere about failures from them and on the rare occasion it happens I've read they are designed to fail externally so as to not destroy a motor

We sell a lot of the Stainless Marine 525efi manifolds. You will not see a loss of performance with the SM manifolds. http://www.diamondperformanceparts.c...cat=272&page=1

Wow, that certainly is disappointing, especially the "rotted out" part, although 5 years is probably around the time any of these stainless headers would start to show signs of failure. The key to header longevity, especially in salt, is to keep them cool as possible, fresh water flush religiously and drain them down when they've cooled. Sorry this happened to you.. been there.. but thank you for posting.. I've been wondering a lot about those Hardin headers...

The 525 OEM spec headers did have issues. OEM went with their own specs. given to CMI.Most headers are going to crack from heat or if they are under stress from the boat flexing. If you have a staggered set-up the fwd engine is going to have more of a chance of header cracking. If you run in salt water I would use SALT-AWAY this is a neutralizer for the water, even fresh water has corrosive tendencies, higher mineral content. If you want to get headers to last flush them out and install a drain valve. Double check the type stainless CMI uses verses Hardin. Hardin makes some lower cost headers that are ceramic coated internally. That primary tube is steel, which will rust out if the ceramic cracks or flakes off.

Gonna reach here a little but has anyone ever considered whether or not the header manufacturers use the correct rod "all the time"? I know that in our line of work you can use many variances in filler when welding stainless pipe but if you don't use the correct filler then the weld fails due to corrsion faster than any other part of the item. ..not only is there a difference in quality of stainless but if you weld with a different alloy then you also create your own self-induced electrolyisis in salt water cause there are now dissimilar metals within the stream on top of one another. Theoretically, the further away the two are in nobility then the higher, faster the rate of said disappearing act.

It's all relative to use and maintenance etc but you can weld the tubes up using the wrong rod (cheaper) and they will last for quite a while but will fail sooner than what's usually expected. I spend time in weld shops and i see them often grabbing whatever is available for almost an infinite number of reasons or excuses.

But I donn't know for certain -

Why does everyone come on here, b!tch about CMI and their multiple failures but yet when people give you the manifold that won't leak (Stainless Marine) , it doesn't even get consideration.

For all the people who have read that they can put SM on their 525's and will never have a problem but refuse to do it for whatever reason, please don't come on here and ***** about your leaky CMI's because you were already told what you should have put on your engines.

Rant over...

3 Reasons -

1. They're upset and the internet is a great place for them to feel as though "people are listening".
2. They're also not real interested in doing a search and reading what's already there because half the interest in a forum is posting your words.
3. Most of us don't own a 50 foot Nor-Tech (awesome boat) and a 40 foot Intrepid (another friggin' awesome boat) and so when your only posted option is to start removing what little "bling" you had it very quickly becomes an answer you don't wanna hear even though it may be true.

How many guys really accept the advice from a divorce attorney and never question it???

Life's tough. Life as a boat owner is tougher -

..and to say you will "never" have a problem with SM in salt water.. well that's still arguably just another matter of time.

CMI's are like that wicked hot chick who always wants expensive dinners and gifts, then dumps you anyways.

Stainless Marine's are like that sorta plain chick that gives wicked good head, makes a hell of a good lasagna, and keeps her mouth shut when football is on.

They are blinded by the bling. Personally I wouldn't hesitate to run SM as I have on 2 previous boats. Simple and effective design and they sound great with 0 performance loss VS CMI'S. I say that it's a no brainer...but then again I don't own a $300k boat.

So, Primary runner length, header size, has nothing to do with scavenging exhaust gasses or either the engineering; which = cost.

Here's a technical article, that will explain the importance of exhaust flow and scavenging. If you have a stock engine and want to improve the performance, moving up to a better manifold, with the same style runners, I could see. Taking a 525 EFI and changing header design to a short style manifold is going to effect performance and combustion chamber temps.
When spending money on a engine and wanting to not leave performance on the table, you better have the proper exhaust. It doesn't matter if you have a twin engine boat running over 1000 hp or a small block making 500+ in a single engine boat.


http://www.epi-eng.com/piston_engine...technology.htm

I've heard the SM make the same or more power on the dyno, have you or any other engine builders tried back to back tests?

But hey your and engine builder so, the more leaky CMI's the better for you.

^^^^^^^^ that is what I would like to see, some real dyno tests one with CMI one with SM.

I always was taught on a NA motor it's pretty Important.

That; I can't verify. I haven't done back to back. If I'am not mistaken SM offers a stock replacement and the Dominator Line. Take SM top one and compare it to Keith Eickerts, cast alum exhaust, those runners converge at about 15-16", those are great manifolds.
What I am hearing from this thread is; the CMIs are all about bling, they don't hold up and you don't need a properly designed exhaust, unless you have over a $300k boat. NOT TRUE

Looks like you have 2 nice boats, according to this thread; you could take either a couple of 55gal barrels or trash cans and cut the ends off and weld them together for an exhaust for your turbine boat.LOL!!!

Hahah that's pretty true

Here's a easy way; not all of us dyno with the boats exhaust. I for one will sometimes. I use headers with a primary of 2 1/8" with 8 O2 sensors. So installing 8 O2 sensors in a set of marine headers isn't going to happen. You can pretty much tell; with injector fuel flow and O2 # data from dyno to boat if the headers are getting the scavenging done. If the O2 readings go rich, the engine is being restricted, if it leans out; well you get the picture.
Yes, exhaust flow is important on a NA and a forced induction.

I DID have one like that once...

I would like to have a set of headers on one of my boats,,,,,,,but after all the bad stuff I hear about the headers leaking ,I will pass.my 10meter has ssmarine manafolds and dry risers.i will say this about ssmarine products.the last,and last,,,,and last some more.my first go fast boat was a 22pachanga.i put ssmarine manafolds and risers.this was in 1998.i sold the boat years ago.two different people owned the boat after I sold it.the new third owner I know.those manafolds and risers are the same ones I bought in 98.the boat has had blowers motors,big inch motors and a host of other motor combanations.my point.stainless marine make good stuff that last.

How about having to pull heads or engines to gain access to install fixture to re drill bolt pattern on a twin side by side or even a tight single? Or is it possible to gain enough room to install fixture and re drill? Most people would have to pay a shop to do that. I had SM on a staggered 33 Powerplay and the forward motor broke two sets of flanges off manifolds at tail pipe and manifold flange, where clamp goes, in under a 100 hrs. The set up was custom built by Stainless. So they are not unbreakable either. Yes it did have long tail pipes and were well supported. Powerplays are well built boats but I guess it was still flexing because of length. Stainless did warranty the first pair. I still think they are very good manifolds and customer service was very good. But you will still have to add in the extra install expense for 525-700 SCI applications and they are not indestructible. As we all know salt loves aluminum too. I now have 600SCI's, in my Spectre, with good ole proven CMI etops adapted by Teague Custom Marine to fit header flange bolt pattern and bungs installed to bolt antifreeze reservoir to. I sold the sweepers off the 600SCI motors and purchased etops and plugged right in to my existing tail pipes from my 575 SCI's. Old etops were 11+ yrs old and sold with motors. Never had an issue.

Everything in boats has its issues however breaking a flange is nothing compared to grenading a motor. Again the cost to remove the heads to drill is still cheaper than a full rebuild. Ill take that piece of mind all day long

That's interesting... so you were able to use ETOPS on the 600SCi?

Here's a picture of the SM Jig. We use a right angle drill when the engines are in the boat.

Yes Teague is a dealer for CMI and will modify them. They weld about a 1/4 to 1/2 inch, something like that, talk to them for exact modification length, to end of flange and re drill holes to correct location. Then install side bungs on starboard header to be able to modify your antifreeze reservoir bracket. Looks just like they came from CMI made that way. Dave at MDG in MD did the install of headers for me and the tank bracket mod. But if you had the sweeper style header on the boat you will need tail pipe modification. I already had etops on 575sci so they fit right up to existing tail pipes. You can see the etops and bungs in the pic I posted. Double click on pic to enlarge.

I once found an old spreadsheet on here that had dyno info from lots of exhaust types. SM, Imco, CMI, etc. If no one has found by the time I get back to the office I'll post it.

Which manifolds is stainless marine using to replace the sweeper headers? I had the old style sportubes and just replaced them with the gen 3 manifolds. The manifolds pretty much perform the same as the headers did. I don't have very many hours on mine, but in the few hot passes I've taken it seems like I'm gonna be within 1 mph. That's on hp 500's with small blowers

here's the link to the thread - http://www.offshoreonly.com/forums/g...no-charts.html

Note: the more 'cam' an engine has, the more 'headers' (properly sized of course) are important. Yes, the KE manifolds are true headers.

The 525 EFI has a buttload more (yes, that's a measurement) cam than the HP500 had.

SM makes a great product but they're not going to make more power in the 4000+ rpm range on a 525. The loss may be minor enough for the peace of mind trade off however, but that is subjective. That being said I'd run SM or KE exhaust, but sooner or later all manifolds will rot from the salt water.

Hey Guys for what its worth I just don't know of a product at least a header that if not properly flushed and or treated with Salt Away that will survive in a salt water environment. So no matter if we build them or CMI or well who knows who else, you need to know salt water is bad corrosive stuff and kills all stainless steel exhaust..

The headers in question here were returned to us for evaluation as prior to seeing them had it been a product failure even well out of warranty we would have stood behind them but the headers returned to us for repair were literally crumbling as in rotten.

We just can't control mother nature and how a product is cared for. So while were using the very best US Made 316L heat treated stainless steel you all need to know it still fails over time. This isn't news to many of you but to some based on the amount of money they spend on a product means it must last forever well just not so in the exhaust world.

While the possible cure would be Titanium the cost sky rockets to over triple the cost. We do know there's a real 525 direct bolt manifold system with NO DRILLING required to show its face in the up coming future as well. But honestly if neglected almost everything will succumb to the damages of corrosion.

Hardin -

Are your inner and outer tubes both 316L ?

And what material is used to weld them ?

Last and - And, what measures are taken to make sure only that welding material is used ?

Sorry if this info is on your site and I haven't remembered.

YES Both tubes are 316L and are welded with AWFSS materials. Then the headers are heat treated and passivated for superior product compatibility.

One last question - where country are the metals sourced from and where are they assembled ?

Yes, it means a lot to me and most of my customers + friends.

Thank you so much for your info.

100% United States of America from the leading source of aerospace tubing in the country. As the matter of fact not only do they NOT import but they are the leading exporter of stainless steel tubing with three manufacturing mills here in the USA..

As a side bar note, no marine exhaust company in the United States could if all combined order enough material to make importing tubing feasible. This industry is much much too small.

Oh yes sorry forgot to cover the where question? All of the products are assembled in our Ohio manufacturing facility by us guessed it 100% US Citizens.

I would think Hardin would be cheaper made than CMI, most of there stuff is imported.

Didnt CMI have a problem with the garde of stainless that wasent marine grade, I would think they have worked thru all there quality issues