4195

Okay i need some advice on headers. I have a pair of 675HP Keith Eickerts with CMI's. I am rebuilding them soon and want to put new headers on. I know all the issues with CMI's but my question is, are all the headers or just the ones on the 525 that leak. How about Lighting headers any fed back on these? Will I have to change my tail pipes? Any thoughts or advice or ideas?

B BOATER

Nope the big tube ones on the 700 scis leak in about two years

Downtown42

f CMI

PARADOX

ALL headers will leak, one time or another. You hear about the 525's since more 525's out there then anythng else. The top 3-4 headers will perform well. Some preventive maintainence is the key.
Allways drain them after use.
Replace the "soft" rubber boot at the tips to HD, wire filled exhaust tubes. Stop viboration / movement of the headers.
No movement, no cracks.
Install a tie bar on the top of the headers and connect left to right. Make the headers a rigid part of the motors.
On CMI's (sport tubes, E-tops, gen X.) if you rally want to add some safety, weld a few short beads connecting the 1/4" gap from the outer tubes to the flange. This is their weak point.
Soon you will see a header design that will solve ALL leaky header issues. The prototype is being made. We have some details / dimensions to work out. You will be amazed of the concept.

rexcramer1

I guess the better question is do only cheap ass Mercury CMI headers have issues, not just the 525 ones, or do all CMI headers have issues?

park35

Frank I am no expert on the subject,all my friends have headers and they all have leaked at some point usally about 3 years max,they flush all the time,I would freshen your motors then look into gen 3 manifold by stainless marine I was very happy with there product,if you lose 25hp per motor for the ease of mind of no leaks,you would be a lot happier,just my 2 cents,good luck with what ever you choose

4195

It is so frustrating to think about spending $8,000-$10,000 on something that can potentially destroy $40,000-$50,000 worth of motors. Has anybody heard any feedback on the Lightning headers?

SS930

Frank,

If you want to be safe, go with the SSM manifolds... but they might give up a little power and I know they don't have the 'look' you want under the hatch.

FWIW, the Stellings on my OL are dated 1999 and have never had a single issue and have never been repaired, despite being overheated etc. That's not to say they wont leak tomorrow (although they probably will now!), but that's a pretty impressive run for a set of SS big tube headers! Based on the track record and quality of their construction, they would be my first call if looking for a new SS header!

Also, if you're that worried about it, install a drain on each and drain them everytime you use the boat... they cant leak into the cylinders if there's no water to leak.

B BOATER

None of or previous CMI headers leaked. They should hold up with three years of use. Remember we have short season here only 3 months or so of boating split that by actual usuable weather and weekends that's not much use. Plus always has been in fresh water. Drained and winterized in a heated garage that doesn't get below 50. We winterize just in case or if we are going to go to havasu.

rexcramer1

Man I would hope they last three stinkin years. $10000 every three years for headers is rediculous.

For 5k a set you would think they would last 10-15 years.

The sad thing is that people that keep going back to CMI for headers to replace their old leakers are actually helping them PROFIT from making crappy headers in the first place