Word to the wise, Drain em down after every run. Also, pull your headers off at the end of every season. Have them pressure checked and heat the inside of the tubes with a torch if you have too....it makes the leaks come out more....

In the past 3 years I've had to fix leaks 2 times of which there were 1-2 leaks in 2 out of 4 headers.

It's a yearly ritual.....

Just unscrew the little blue draincox right? Also, converting to a dry exhaust will prevent bad things from happening???

Yup, If you have a little drain then that makes things easier! Only drain the header though, not the whole motor. ;) It's not fail safe but if you have a tiny leak in one of the header pipes it well keep it from draining down and back into the motor.

Switching to a dry exhaust wont help any....unless the exhaust isn't water jacketed....kind of like a header in a car or drag car or garvey lake boat etc...

KE, KE, KE, KE, I'm telling you, it's the way to go!
Dean

Could you re-explain? I don't speak Spanish!!!:evilb:

[QUOTE=Panther;2147746]Word to the wise, Drain em down after every run. Also, pull your headers off at the end of every season. Have them pressure checked and heat the inside of the tubes with a torch if you have too..

Man if I did that I'd never hear the end of it from my girlfriend about how anal I am. Don't even go there guys, I can never make her understand. I thought CMI was the way to go but after this thread, count me out!

Had CMI's on my last motor. Found out I had a leak after the fact. Blown motor! ,Cracked Block!, Sent them to CMI for testing and repair. Port side it great starbord is junk and can't be repaired. They claim they only last 7 years. They are 7 years old. any one got a good starboard for sale? or want to buy mine with tail pipes? Just got a set of KE's

I had a header on one of my 525's start to discolor and had it replaced before it could take a dive. But I was told that because of the funky bolt pattern on the heads that the CMI is the only one that will fit because it's made just for that motor. Is someone else making a header now that will fit?

This is what I heard as well, that Mercury changed the bolt pattern from what has been GM standard for a bazzillion years and as a result the CMI is the only option - anyone got confirmation either way??

Just for information, most any stainless headers with a big block standard exhaust bolt pattern can be redrilled to match the Mercury Racing exhaust pattern. The reason Mercury changed was that there are a few bolts on the headers that are a ***** to install and remove on the standard chevy pattern with stainless header flanges. One of the contributors to stainless header leakage and cracking also comes from movement and vibration which is greatly increase with long tails such as in staggered packages, etc. Get good supports made for those puppies! I think with the cost of motors you stainless header owners at the beginning of each season should rig a simple pressure tester fitting and hit them with let's say 50 psi air pressure, cap the pressure and watch for leakage. Got leaks! Don't run'em until repaired! An Oz. of prevention worth a pound of cure! Seems I heard that somewhere before?

Regards,
Ray @ Raylar

If need be, I would assume (since they are aluminum heads) that the holes can be drilled/tapped into the heads for the old style header or a Stainless Marine/Keith Eikert bolt patterns?? Worst case, a welder can fill the holes in the heads and drill/tap for the old bolt pattern, right??

May be a lot of work but if someone is doing a rebuild...especially if the rebuild is due to header failure..:eureka:

I am switching to eddie marine headers. dont want to replace anymore engines.

So what do you do if you want to purchase a used boat with 525's?

I ran Stellings for a few years in fresh water, set up a pump that drained the pipes and sent the water overboard after I shut down. Finally said the heck with it and bought some KE's aluminum castings. 400+ hours and life is good:D

Brand new set of CMI's pinhole leak port side at four into one weld location. Leaking to outside big problem/ little problem?

Mine developed a pin hole external leak also. In and of itself my understanding is that it represents a little problem. However, it is indicative of corrosion and raises the ugly spectre of internal leaking.

you would think that CMI would have a little better quality control, maybe use a different grade of stainless, or make the tubes thicker, there has to be an answer

I had a guy that had a shop next to mine in Naples that was a excellent welder.He had moved over from Miami and just had huge pile of Stellings laying aroung to be welded all the time. I used to spend quite a bit of time with him examining failures.


Being i had just purchased a new set of Tubular headers i was very skeptical about my new purchase after seeing how many he repaired all the time.

From what i could see and from talking to him many of the problems stemmed from overheats or debri clogging the jackets and causing a hotspot . Vibration and lack of support for long heavy tailpipe -muffler combos was a problem also.From what i could see failure was just the nature of the beast.

Easy way to tell is to loosen up the header and pull it away from the block and see if any water has settled down into the bottom of the tubes. Then I usually crank the engine over with the spark plug removed to see if any liquid (water) shoots out of the spark plug hole (it's best to do this with a starter button hooked up so you can crank it while you're in the engine room). If water shoots out you either have a problem with the header or a head gasket or even a hole in the head....

The rise in oil level is strange.... Is it milky in color?

Yes, and you would probably see air bubbles in the heat exchanger. You would also smell the burning coolant and have white smoke. Sometimes the coolant leaks past a blown headgasket and into your crank case...

stainless marine I have owned them for 13yrs lovem art