Finally tore down the old engine.

[krisnowicki]

So I pulled the old engine out and am putting the new one in. NEw one is all together and ready to go in next weekend. While I was cleaning up the garage I took the heads off and, the top of all the pistons on the port bank was rusted. I didnt pull the star bank yet. The engine was fresh water cooled, so the only way this water could have gotten in, is through the exhuast.
The engine did not have any shutters installed in the exhaust, is this the most likley culprit?

The manis are new on the new engine.

 

[NHGuy]

Re: Finally tore down the old engine.

I understand the shutters are there in case you get a big wave at the back of the boat, or if you have to cut the power while backing down. They are supposed to keep out the wave. I assume that they are mainly for when the motor is off or turning too slowly for the exhaust to effectively push back the water. From what I have read, (haven't been unlucky enough to have it happen to me), failed water jackets on exhaust manifolds are the most likely place you'll get water into the combustion chambers on a normal marine engine.
But if it's a car engine or has a "hot" cam, you can get water in the engine through reversion.
Reversion is the scavenging action that occurs in the exhaust at lower rpms in which exhaust water gets pulled back up into the motor. It can ruin a motor.
Search any of those terms and you will find tons of discussion on the subject. A veritable plethora!
And if I didn't hit my descriptions just right folks will be along to update or correct me too. Water in the motor is a pretty well documented topic.

 

[krisnowicki]

Re: Finally tore down the old engine.

I would think if it was manis It would have been mainly in cyl 3 and 5 not all 4. 1357. I mean shutters are going in and the exhaust is on the new engine and runs good with no leaks. Just trying to make sure I have cured the cause of the prior failure