Several years ago I wrote a post about one of my 500EFI headers leaking, and got flamed pretty bad. "How dare I say anything bad about those highly polished stainless steel headers". Even the guy from CMI posted back about how I had to be full of $hit. I posted photos of the poor welds and swiss cheese metal (what was left of it, anyways). That was the end of most of the comments. My friend is a surgeon when it comes to tig welding, so he took it apart and fixed it. He also cut out the swiss cheese reversion cones and made new ones out of 316L SS. I think I still have a couple of those reversion cones he cut out laying in one of my tool cabinets. Several "factory" welds were terrible where they started and stopped; when we pressure tested the header with 40 psi, it looked like Mr. Bubbles with several of the welds having pin holes. The header to tailpipe weld was especially bad - and it was not saltwater damage. As far as I know, most inland lakes and rivers in are pretty much freshwater (well, maybe not the Ohio river ... not sure exactly what that is ;) ). I've had 4 500EFI engines, 1 575 SCi, and now a 525 EFI and out of the 12 individual headers, I have had to have 3 fixed for leaks (not the 525 EFI, but the previous owner had to have one of them fixed, I drain them at the end of every use, for whatever that worth). Most have leaked at the header to tailpipe flush face weld. I do not know what metal they use for the reversion coned in the E top style (older) headers, but it is really $hitty metal ... Sorry for the long post, but I'm not a big fan of the CMI/Merc headers. :rolleyes: The headers on my 525 scare me.

Yikes, any issues with the CMI's on the ILMOR's ?
What is the best way to check them?
Should I pull mine? Can I pressure check them without pulling them?

Your not alone!!

As far as I know, there were 2-3 years where there were problems. It was the first few years the 525 was produced. The headers that were a problem have the outer tube that goes all the way to the header flange. The later model ones that were supposed to be better, have the outer tube that stops short of the flange and tapers in and is welded to the inner tube instead of to the flange. Hope that helps clear it up.
Eddie

My 525 EFI headers are the one's with the outer tube that stops ~ 1/4" from the header/head flange. Are they the old style or new style? Not sure where it was leaking, but the previous owner had to have one fixed. I visually can't see where it was fixed. Boat is a 2006 model, so engine is probably 2005 build (it has the "new" style fuel filter, if that helps).

If I had a boat with triple 525's, I probably wouldn't be able to sleep at night ... just think ... six of those headers, just waiting to ruin my "pleasure boating" and trash the engines, my wallet, my 401K, my kids college funds, and so on. But wait !!! I can buy the new improved models for only $8000 a set? :D :D

If this would have been in the automobile industry, Merc would have probably had to do something by now ... remember the Toyota engine sludging problems of the late 90's/early 2000's?

yup, that's how it goes.

That is the newer style header. However, that's not to say that they can't have problems. It is just not nearly as common.
Eddie

Well there goes my dream. $8000 for manifolds for a 525 alone makes it all not worth it. If I have to go that fast, with 8 grand for the manifolds I'll buy a flat bottom drag boat.

On mercs HP series of motors......Everyone (Dealers, Salespeople, fellow boaters etc) has always said "Merc will stand behind thier motors" as opposed to independent builders such as YPM. This has ruined more peoples motors than are being talked about on here. I can't believe Mercury has not been in a class action lawsuit over this. Deep pocket guys just shell it out and get even better exhaust....but the average person that finances the boat for 15 or 20 years does not have the disposable income to shell out $16K to $24K (twins or trips) to just be able to have piece of mind that you are not going to have a total meltdown of your motors that run great. It is not a question of if....its when. I understand warranty and when it expires, it expires.....but for what they get for thier products.....my expectation is to get a properly designed, tested and reliable package. That is not what this set up is. Now that Merc is loosing that edge, I would think that it is swinging a lot of business into the independent guys like YPM. I have a set of YPM engines and a set of Teagues and they both stand behind thier products. Merc used too.....

What if the new 1350 Merc has a similar issue that gets it through the warranty...but ruins the engine with damage that is substantially more than normal wear and tear that the engine should have based on the time. It is a fundemental engineering error of the wrong components and you call them up to explain and they say....you are out of warranty.

For comparison, I have a set of 1998 Stelling Big Tubes that don't leak a drop and never have. They are an equivalent price and that is the kind of longevity that you would expect from a set headers in this price range. Headers should last 3 or 4 total rebuilds in my opinion. Maybe I am out on a limb....but jeez!

Always nice
 

Its always nice to see another great American corporation going bad.

Was talking to Tyler Crockett today about the new Merc 502 engines that just came out this year. He has rebuilt a few brand new Merc made 502s with the block decks cut so out of parallel that the compression varied from 8.75 to 7.00 across one head. Main caps not installed in the correct marked locations. New owner appreciated these new Mercruisers in his new boat. Come on Merc, new boat sales are bad enough with out this.

Reminds me of working for General Motors - great production facilities - outstanding design and engineering departments - problem was top executives - no one at home - just pirates - wonder if they will vote themselves another large bonus and salary increase this year?

PIRATES AHHARR!