I never had any idea that the failures and problems were this wide spread and they seem to keep coming. This is really a horrible situation for both CMI and the Mercury Racing engine customers. This is also not good for the industry and such as it just helps nail another coffin nail in the performance marine industries barely floating ship!
Just my two cents here and some of my simple engineering training and experience, but CMI's idea for this "cool collar" gap between the outer header pipe and the header flange seems like a mistake to me. My thought here is that these headers are fairly heavy to begin with and they tend to vibrate and flex when the engine torques and the boat slams or pounds as all do. This reduction in the strength of two pipes welded to the flange would seem to put a lot of stress at the bottom welds and added heat from a section exposed to 1250 to 1400 degree inside exhaust gas temperatures with no outer cooling. If a lot of the cracking problems are showing at this location then I think my thought and ideas may be well founded.
In getting heads around this header problem, if Mercury pushed their ideas, production designs, material and method specs. on CMI, then I also think Mercury should step up and bear some of the cost and responsibility for this problem that obviously many of their customers have suffered. I know some would say that once they are out of warranty the responsibility supposedly ends, but if Mercury and CMI were responsible for a obvious down the road problem for their engine customers I would think they should have let the customers know at purchase time that they may be experiencing these possible issues down the road as they do with valve train life issues and have made time certain checks on the headers for customers to make sure they do not loose engines and such. If these headers have a fixed life in use then just define it and let the customer know he has to budget and plan for replacement before failures occur.
In any event I as well as most in the industry would like to see this kind of product problems slow and stop and see the performance boaters stop suffering through these kinds of expensive and costly problems. This is bad for all in the sport and industry!
I feel that CMI headers have always been considered an excellent product for most of their history and I hope they can return to problem free products and a great viable future for our industry.
Ray @ Raylar