2002 Crownline 262 CR 5.7 B3 Hydrolocked broken valve trashed cylinder

[dollar7499]

Some history, I bought the boat in the fall as a project, it had freeze cracked on the PO and he tried to replace it with and old SBC 350 non vortec so I yanked it and installed a junkyard 1998 truck block I put brass freeze plugs into. Been having an awesome summer towing it around the southeast and boat camping everywhere and this weekend in a mountain lake in NC I had about 9 people on board all in the cockpit and was taking a loooong time to get planed out. Then it started running bad and dies. I get everyone on another boat and open the engine to find milkshake foaming out of the dipstick tube.

Back home, pull the exhaust and find water in the center exhaust manifold tube on both sides. Flappers look limp and shiny, almost melted, but this engine has never overheated. Cylinders are full of water and one had a valve break and trash the cylinder and piston. The exhaust gaskets ripped apart upon disassembly, but look like they were intact and complete.

1. Could the valve have broken before and caused the incident in any way?
2. I have the exhaust with 6" spacers on the risers, but could being so heavy in the back (with 9 ppl trying to get on plane) for so long with bad flappers wash water up the y pipe with full throttle exhaust pushing back against it?

Please help me figure out what ruined my 3 month installed engine.

 

[Scott Danforth]

where was the static water line with 9 people on board?

if the flappers are shiney and not rubber coated, the rubber long since got burned off

most likely the weight of people (tell them to move forward) squatted you so much that water was pouring into the manifold and hot valves and cold water dont mix.

 

[dollar7499]

Hi, thanks for your response! My thoughts are that it might have been something else because the spacers make the elbows so tall the swim platform would have to be in the water to get some past the elbows. Even then, I drained a gallon of water from the oil pan (should have mentioned that in OP) Not sure if that much could have gotten over the hump there...

I guess since I am replacing the engine and flappers I will have someone plane the riser and spacer mounting surfaces and rig up a pressure tester. Anything else I can do to protect engine #4 when it gets here??

 

[alldodge]

Still think Scott has the answer to what happened. Everyone was up front to get on plane, now your on plane. Slow down and water comes up and rushes up and in.

There is a guy hear which had several sitting on his stern, others in the water enjoying the day. Did notice a few times that waves would come up a bit higher then should have and was worried. Well decided to go for the day, and turns the key, and hydrolock.

It only takes once and you got about a gallon out of the motor

To protect for next time, and if you have the room, install some 3 to 6 inch risers to lift your elbows higher

 

[Bondo]

1. Could the valve have broken before and caused the incident in any way?
2. I have the exhaust with 6" spacers on the risers, but could being so heavy in the back (with 9 ppl trying to get on plane) for so long with bad flappers wash water up the y pipe with full throttle exhaust pushing back against it?

Ayuh,...... I've got a slightly different take on it,......

I think with the heavy load, you were detonatin' when tryin' to get on plane, which smoked the valve, 'n there's probably now cracks in the head, or heads,....

A cracked head will dump a fair amount of water into the cylinders,....
After the motor died, ya still had a huge load, 'n with that many folks movin' around, more water, may, or may not have slipped past the burnt shutters,.....

 

[dollar7499]

Hi everyone, I have an update and a 'chicken or the egg' question. I got a really bright light in that #7 cylinder that had the broken valve trash it and found a crack running up the wall in between the water jacket and piston. That explains the water completely filling the block, did that cause the valve to break or did the broken valve crack the side of the cylinder? If the crack happened first, what could have caused that crack after 25+ times running this season and no heating issues??

And do the flaccid flappers figure into this at all??

Thanks again for helping me figure this out down to the source before my new long block goes in!

 

[alldodge]

Don't know, but water in a cylinder will brake things. The flappers help keep a quick slosh of water out, but will not help if the there is a large in rush of water

 

[dollar7499]

Thanks, AllDodge!

Does anyone else have any thoughts on my cylinder crack and broken valve? Any other places I should look in the engine to confirm?

 

[Scott Danforth]

Thanks, AllDodge!

Does anyone else have any thoughts on my cylinder crack and broken valve? Any other places I should look in the engine to confirm?

my thought is build a 6.2 (377 or 383) stroker to replace the 5.7 with your big and heavy boat. as to which came first, the chicken or butt-nugget, not sure either way, the motor is coming out and something else is going in.

 

[Bondo]

I got a really bright light in that #7 cylinder that had the broken valve trash it and found a crack running up the wall in between the water jacket and piston.

Ayuh,..... Burnt, busted, tuliped valves can result from detonation,.....

 

[dollar7499]

I installed the new 5.7l long block, upgraded to flat top pistons with the engine builder, hopefully that's worth a couple extra HP. Working through some stumbling / surging under load, re-checking timing, plug wires, etc. Hope its not a fuel issue, I just replaced the fuel pump and rebuilt the carb.

 

[scoflaw]

What's your CR now with flat tops ? Could be the kiss of death for #4

 

[alldodge]

Could be the kiss of death for #4

Why only number 4?

 

[HT32BSX115]

Why only number 4?

I think he's saying he's on engine #4

Anything else I can do to protect engine #4 when it gets here??

For the OP, how tall (what length) riser extensions are you using?

 

[scoflaw]

Why only number 4?

4th engine, apparently. Might of misread that

 

[dollar7499]

Hi, thanks for the replies, I am on engine #4 (original PO cracked, 2nd PO installed wrong non-vortec engine and sold to me, 3rd got water from exhaust and cracked cylinder or just randomly cracked cylinder.)

I have 6" extensions in between the manifolds and elbows. and brand new shutters / flappers

No idea what the compression ratio is with the flat top pistons, just trusting the long block builder on that one. Couldn't afford the stroker so he suggested the pistons as a mild upgrade.

 

[Scott Danforth]

What's your CR now with flat tops ? Could be the kiss of death for #4

9.4:1 with 64cc heads (vortec heads). same as VP for the past 30 years

 

[Scott Danforth]

Hi, thanks for the replies, I am on engine #4 (original PO cracked, 2nd PO installed wrong non-vortec engine and sold to me, 3rd got water from exhaust and cracked cylinder or just randomly cracked cylinder.)

I have 6" extensions in between the manifolds and elbows. and brand new shutters / flappers

No idea what the compression ratio is with the flat top pistons, just trusting the long block builder on that one. Couldn't afford the stroker so he suggested the pistons as a mild upgrade.

a stroker is same cost as a 5.7 motor as a new stroked crank is same cost to grind your existing crank ($230)
rods cost more to recondition than to buy new
pistons are the same cost.

a complete 383 SCAT stroker rotating kit is $730 - cast crank, cast I-beam rods with hyper eutectic pistons... , $915 for kit with forged pistons and about $1500 for all forged parts

 

[dollar7499]

Yup, it was $1850 for a long block or $3250 for a stroker long block..
He offered the pistons for $100 extra so I agreed.

 

[scoflaw]

9.4:1 with 64cc heads (vortec heads). same as VP for the past 30 years

My math says 11 to 1

Dome volume 5cc
deck clearance .025
gasket .040
cylinder head 64 cc
Bore 4.030
stroke 3.48