454's ingesting water

[Carl]

Does anyone recall hearing about the issue with the 454's ingesting water, I've been searching with little result. It had something to do with valve overlap, risers thats about all I recall.
Thanks,
CArl

[Ryan]

My fathers 454's had injseted some water a few years back. It was the gaskets between the exhaust manafold and the riser. The engines where only three years old. Water would trickle down the exhaust port when boat wasn't used and wound up doing major damage to valves / heads.

[Mack]

I cannot stress enough how important it is to use quality gaskets for your risers and manifolds. I had my manifolds replaced two years ago and the mechanic that I used at the time installed them with a set of paper/cardboard gaskets that came with the pair (Osco). At the end of last season I noticed an abnormal exhaust smell while running the boat. Checked it out and noticed the gaskets were begining to fail after only two seasons. New mechanic replaced them with a Mercruiser standard issue set- the ones that should have been installed in the first place.

A total failure of the old gaskets would have sent me to the rebuild shop.

[scot]

Sim,

Yes it can be about valve overlap. Camshafts have 2 basic functions: 1) open the valve to a specified amount (lift). 2) Hold the valve open for a specified time (duration). IF the cam in a particular engine holds the valves open too long, both intake and exhaust are open at the same time....this is considered "overlap". IF this occurs during the piston's down stroke the exhaust gas+water can be sucked back down into the engine. It is this excessive
overlap that creates the lumpy, rough idle hot rod sound...it also makes horsepower.

The goal of any marine engine designer is to maximize the cams lift while keeping the time the valve is open, or duration to a minimum. So, for marine applications use: "High lift~ short duration" cams.

The only way I could imagine this happening to a factory engine would be: "Maybe" a high horse version engine is idling too low. The higher horsepower engines utilize cam profiles that have more overlap and if the engine is idling too low it "could" create a problem...i.e. water sucking back into the cylinders.

This would only be a theory on an OEM engine, but it's a fact on back yard build hot rods that end up in boats.

The moral of the story is don't stick a hot street cam in your boat motor thinking your going to end up with a faster boat....unless you REALLY know what your doing!

[John F.]

The 496s had some problems due to some slight valve overlap as I remember. I think the CC25s had alot of problems.

[lobsta1]

Don't remember exactly the years, but the 454s from around 1999 to 2002 had a serious problem with injestion. Some Sea Rays, Albemarle & Cruisers had to have engines replaced several times. Sea Ray 31 in particular. Engines were mostly Mercs but also some Volvos.

Apparently the engine installation layout did not have the risers high enough above the water line. Then when idling back in to port, water was sucked back in through the valves. Get back into the dock, shut down & then the rust starts as the water vapor was not being burned off.

Rick, on the B33 sportfish Ticket, replaced his gas tank last winter to avoid any risk to his engines. He had repowered in 2000 with Mercs.

This summer he lost his port engine not from the gas, but from water ingestion. The whole inside was a rust bucket. (He had already replaced the risers & manifolds after the 2005 season, so that was not where the water came from.) He plans to rebuild his stb motor this winter, BEFORE he suffers a catastophic loss on that engine. The port engine heads were so bad he had to replace them.
Al

[Harry Babb]

Sim

I remember that Randall talked, in a recent post, about injesting water but his situation was related to backing down to hard.

A simple burnt or leaking valve or misfiring cylinder will cause the engine to suck water back into the cylinder.

Harry Babb

[randall]

hell...ive had water in both engines at one time or another and they still keep on runnin..(not to mention the dreaded black goo)..take out the plugs....fill the cylinders with something oily........spiner over a few times...change the oil and you good to go.....if you lucky...................................................luck counts

[Carl]

Al, yes that is what I was refering to factory engines sucking up water or maybe it was just vapor after shutting down. If it where only Merc's and Volvos that would be promising.

Anyone know a good place to follow up on that information. Looking at a 1999 32 Luhrs with 454 Crusaders, multiport injection and would like to have information, as to what engines where having issues what was done or could be done to fix or take a pass. Looking at others years as well, but this one is at the top of the list.


Great info thanks.

Carl

[Carl]

Randall, your right if you suck up a good amount or have a manifold or riser go and catch it in time before breaking something.

From what I remenber it was either the vapor coming back and rusting up the valves of the engine or would be pulling water back from the risers on shutdown, especially after a long hard run. In both cases it would be something that happened often and nobody wants to buy a boat where you have to pull the plugs and squirt oil into each cylinder after a run, especially if you go offshore. Besides the engines are under the salon in the Luhrs, not a place you want to go and climb around after a long run.

[alano]

Sim, you can do a search on 'reversion' - been beat to death over the years on thehulltruth.com. Popular conception is that crusaders have closed cooling on the risers and hence aren't as prone aas merc/volvo. It seems(ed) to affected express models that put the engines way low so didn't have enough drop to the exhaust. That being said merc disables smartcraft troll control on thier inboards due to water reversion issues so said a merc rep I got to check into it (self installed 496 engines), also they came with SS risers that suppossedly stay warm to avoid condensation in cooler waters so must be something there. 3 years into them changed the plugs after sitting for a few weeks and no rust evident so knocking on wood - will keep an eye on it. I'm sure Bruce will be able to provide real world advice and would listen to him well. Alan.

[randall]

sim...no one said often.....that would be a problem to avoid.....i plan on tearing the end caps and elbows off my newly installed manifolds (at the end of season) as the engines are generating too much steam at running rpm.....none at idle

[Capt Dick Dean]

Randall, too much steam could be that the manifolds/risers/end caps are not torqued enough. I had a steam problem ( Maureen says look at the white smoke coming out) and it wasn't that bad. But the fresh water cooling system needed extra coolant on each trip. Retightened the risers on the port engine along with the end caps and this did the trick. The exhaust maniflods were fine. Cut down on the white vapor and stopped the loss of coolant.

And that's about it from New York.
Over and out!

[JP Dalik]

Sim,

It may not be a bad idea to go into the engine room and check the height of the risers above the water line. Just cause its factory may not mean its right.
We average around 10-12 inches to the center of the outlets in the B31's. Less than this without lift mufflers,baffles or surge tubes could be very suspect and the cause of water ingestion- gas or diesel.
Aside from Cam overlap and riser gaskets I would cerainly look at the exhaust system in general as another source of water ingestion.
Good Luck