Water in the cylinder - Page 2

Faster · #11 (**permalink**) 01-31-2012

Quote:

Originally Posted by Hartley18

I don't think I've ever disagreed with anything Fast has posted before, but, having seen it happen myself, I will on this occasion.

If there's no evidence of water in the oil, check the Siphon Breaker.. yep, the Reed Valve thingy.

I'm happy to be corrected and will bow to your experience

EDIT... OK, I'm back home and not trying to type with a $#@(*& Ipod....

Cameron can you elaborate on how that happens? With a properly designed elbow and a running engine, anti siphon or not I'm having difficulty envisioning the raw water pushing/flowing back against the exhaust gas flow.

mikey19625 · #12 (**permalink**) 02-01-2012

no water in the oil and the Reed Valve looks good. No cracks, blockage or signs of deteriation. i took the exhaust manifold off and found signs of salt water formation in the manifold top side and inside the head. this defenitealy indicates that water is coming in through the exhaust valve. Maybe a cracked head when under tempeture?

Faster · #13 (**permalink**) 02-01-2012

Can you cobble up a diagram of the exhaust/RWC injection arrangement that is fairly accurate as to elevations? Or some pics? Something is amiss here for sure....

smurphny · #14 (**permalink**) 02-01-2012

Is the head possibly warped or a small dent/gouge in the mating surfaces in just the wrong spot? New gaskets won't help if either of these are true. I also have no experience with this particular motor so just generalizing. Sure you probably know this but be careful of bending rods with water in cylinders.

Hartley18 · #15 (**permalink**) 02-01-2012

Quote:

Originally Posted by Faster

Cameron can you elaborate on how that happens? With a properly designed elbow and a running engine, anti siphon or not I'm having difficulty envisioning the raw water pushing/flowing back against the exhaust gas flow.

To be honest, I'm not sure exactly how it happens because there are so many variations in exhaust set-up... but one given is that the engine is installed below the water-line (and most yacht auxilliaries are, when you look at it).

"Properly designed" is the key here... It seems to me that, if the muffler gets full of water (eg. engine cranked for a while and/or anti-siphon vent blocked) with a badly designed exhaust set-up there may not be enough exhaust pressure at low (idling) revs to blow all the cooling water far enough uphill and out of the boat. If the engine remains at low idle and isn't revved for several minutes, the water level in the exhaust system slowly builds up eventually dribbling back into the manifold.

It isn't a lot of water and the exhaust pipe is never totally blocked, but it can be enough to put the fire out.

Hartley18 · #16 (**permalink**) 02-01-2012

Quote:

Originally Posted by Faster

Can you cobble up a diagram of the exhaust/RWC injection arrangement that is fairly accurate as to elevations? Or some pics? Something is amiss here for sure....

Yep. A diagram would be a big help!

EDIT: Upon re-checking the "installation instructions" book on my Volvo engine - which runs to 52 pages - I think you'll find there are quite a stack of requirements for correct installation of marine engine systems. Heights of the siphon breaker (a.k.a "vaccuum valve"), vent hose, muffler and exhaust outlet above/below waterline and maximum exhaust backpressure are all critical items.

A long shot here, but.. the end of the siphon breaker vent hose wouldn't happen to be be below waterline level would it? That's as bad as being blocked..

mikey19625 · #17 (**permalink**) 02-02-2012

I haven't altered the original installation set up by the manufacturer. The siphon valve is about a foot above the top of the generator. This generator is 7 years old with 400 hrs. Always ran ok. The engine overhaul came about when the original head started leaking cooling water by one of the freeze plugs (corroded). I decided to replace the head, cylinder, rings and all the cooling hoses. I'm taking the head to a machine shop for a Magnaflox ck. Looking for possible cracks or other defects.

Guys, your input in all of this is very well appreciated and maybe somebody else along the way will benefit from my saga.

casey1999 · #18 (**permalink**) 02-02-2012

Not sure if your engine is the same but my Yanmar 3gm has a raw water cooled exhaust manifold. If this manifold corrodes through on the inside, it could allow water into the engine near the valves, and could possibly be pulled into the engine cylinder.

Rockter · #19 (**permalink**) 02-04-2012

Mikey :

Did you put the exhaust gaskets on the wrong way round?
That would explain it.
Have a look.
Is water dripping out of your air filters after the engine stops for a while?

Mikey, ON NO ACCOUNT attempt start that motor with water in those pistons. You will bend the crank in an instant.
.

mikey19625 · #20 (**permalink**) 02-06-2012

No water dripping out of the air filter when stopped and i checked the exhaust gasket and it goes on one way only. This one is rectangular shape. I picked up the head from the machine shop today and they found no cracks or defects. I will bypass the water pump and pressurize the cooling system with a garden hose. That should be about 40 to 50 pounds of pressure, i will then crank the engine several times with the injector off to see if I can duplicate this sympton.