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-   -   OSO CMI Header Education (https://www.offshoreonly.com/forums/general-q/245237-oso-cmi-header-education.html)

Rocker Down 01-07-2011 08:06 PM

OSO CMI Header Education
 
I want to thank all the OSO 150 replies about the problems CMI & Mercury Racing are having with their 525s Headers. What an education, Both engines have been rebuilt because of the leaking headers, and now, I must decide on which new Exhaust Headers to buy. Thanks for the :readinghelp:

Rocker Down

SDFever 01-07-2011 08:48 PM


Originally Posted by Rocker Down (Post 3291511)
I want to thank all the OSO 150 replies about the problems CMI & Mercury Racing are having with their 525s Headers. What an education, Both engines have been rebuilt because of the leaking headers, and now, I must decide on which new Exhaust Headers to buy. Thanks for the :readinghelp:

Rocker Down

Why don't you just buy the big block headers from cmi and take them to have'em drill an extra hole or two in the flange?

In other words, the non-525 headers are fine. It will take longer to setup then to drill the holes..

ShadBurke 01-07-2011 10:29 PM


Originally Posted by Rocker Down (Post 3291511)
I want to thank all the OSO 150 replies about the problems CMI & Mercury Racing are having with their 525s Headers. What an education, Both engines have been rebuilt because of the leaking headers, and now, I must decide on which new Exhaust Headers to buy. Thanks for the :readinghelp:

Rocker Down

Gen-X ????? Maybe next time Merc will leave the header specs to the header folks.....

I replaced mine with Gen-Xs and am very pleased. If you have staggered motors, most likely will need to brace one motor.

northernoffshore 01-07-2011 11:05 PM

stellings

redbud35 01-08-2011 06:12 AM

I surely wouldn't buy CMI's if you starting over.

vette131 01-08-2011 07:19 AM

drill & tap your heads for stainless marine exhaust & be done with it.

30Special 01-08-2011 05:37 PM

X2 on the STAINLESS MARINE !!!!!!!

FIXX 01-08-2011 06:51 PM

Fixx
 

Originally Posted by northernoffshore (Post 3291625)
stellings

+1,,,spend the xtra coin on the stelling's..

Centsless 01-08-2011 08:18 PM

why are we into an other thread about this product......
you want them to last......
TAKE THE TIME TO WARM THEM UP!!!!!!!
TAKE THE TIME TO WARM THEM DOWN!!!!!!!!!!
IF YOU NEED A LESSON ON METALLURGY
i only charge 65 an hr
no seriously.....CMI are a reasonable product..... for the average hp boater
the problem occurs with temp..... overheating of the welds and rapid cooling of water injection at those points
stellings are a better product.... and if you pay $4000 for CMI you will pay $8000 for stellings the math is quite simple
if anyone needs a more detailed diatribe PM me

SDFever 01-09-2011 11:53 AM


Originally Posted by Centsless (Post 3292131)
why are we into an other thread about this product......
you want them to last......
TAKE THE TIME TO WARM THEM UP!!!!!!!
TAKE THE TIME TO WARM THEM DOWN!!!!!!!!!!
IF YOU NEED A LESSON ON METALLURGY
i only charge 65 an hr
no seriously.....CMI are a reasonable product..... for the average hp boater
the problem occurs with temp..... overheating of the welds and rapid cooling of water injection at those points
stellings are a better product.... and if you pay $4000 for CMI you will pay $8000 for stellings the math is quite simple
if anyone needs a more detailed diatribe PM me

I think what you may not be realizing is that specifically, the 525 headers from Merc with a Merc part number is a different quality piece than any other "NON-MERC" CMI part.

Merc told them to make the header cheaper by using less heat treating etc....

In part, this lack of info is what keeps the topic going.

All the other CMI headers are better than the Merc Branded CMI..

Your suggestions regarding the use and taking the time to heat up or cool down is a great idea. Most guys jump out of their diesel truck and slam the door with an 800 degree turbo baking itself to death..

Do you think they will be concerned about a "water cooled" part on a boat?


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