I think God doesn't want me boating....

BlewByYou88

BlewByYou88

Member
Jul 24, 2010
963
Arizona
Boat Info
268 Sea Ray Sundancer 1988
Engines
2X 4.3L 4bbl Mercs w/ Alphas
At what point do you throw your hadns up and say....F* this!?

I went out for a quiet day on the lake this last friday...trying to enjoy out unusally warm winter. Went by myself, just wanted to relax, and enjoy some quiet time with the boat, and a book, and some lunch.

It was a glorious day, warm (78) and sunny. Boat was running great. Started to head back in, I wasn't rodding it or anything, just cruising, about 25 MPH roughly 3000-3500 RPM? When smoke started bellowing from the Vents and hatch. I immidatley shut down, started the blowers, and opened the hatch. I had normal oil temps, levels, and engine temps were about 145?. The STBD engine still had smok coming out of the valve cover breathers, and it had blown the lines off where they go up into the cowling.

Scratching my head, I looked over a few things, reconnected the breathers, and tried a restart. Engine fired right up with out hesitation....but smoke sarted coming from it again, and it started makeing a weird hissing/vaccum noise. shut her down. Idled back in on one engine.

Thinking maybe I blew a head gasket or something...Ok great....My yearly engine pull here we come!!!!!

I ran compression tests on the engine before pulling it. had great comperession on all cylinders, but number one....Flat dead zero. Ok, gotta be head gasket or maybe a valve.

WHatever, I know its coming out. Rebuilt my gantry in the back yard, disconnected the engine, and pulled her out and into the garage. Piece of cake now that I have done it like 6 times. I had her out in 3 hours including building the gantry time.

SO. got her into the garage...I want to know exactly what happened. Start dismantleing everything....and there it was....A F*ing hole in the number one piston...WTF I can't catch a GD break to save my life with this thing....

Any thoughts on what may have happened? I thought somehow maybe some debris got in there, but the top side of the valves are fine. I think the debris in the cylinder is from the chunck that came from the piston and beat the crap out of the head and piston..

Some thoughts guys? :smt089

DSCN1578.jpg
 
Something similar in one of my cylinders - I'm told it is caused by detonation/timing from low octane fuel, which wasn't the norm in '93

Yard is going to tune the other engine (also a 1993) which recently had rebuild so hopefully don't have it fail on me too.

Edit - ill post pics tomorrow when the blown engine gets delivered and you can judge if they look the same cause.
 
Well, I checked my timing, and she was running 5 degress BTDC as the engine is spec to be. I always run higher grade fuel in her if its available....I just can't believe it.
 
Take a deep breath, find something in your life to be thankful for, and don't let it bother you.

It can always be worse.

I've been kicked down so many times over the past couple years I don't even feel it any more.

Did you check the heat range of the spark plugs?
 
Sounds like you were having a wonderful time enjoying some peace and quiet, escaping the hub bub of life, just what boating is all about and the devil just couldn't stand it.
 
Sure looks like a detonation blow out
and with the hot spot in #3 piston I would call it running to lean and timing a little fast.
a couple of degrees too much advanced and a lean mixture at higher rpms van melt the tops right off the pistons
IMHO you have more than one contributing factor here.
 
Didn't see it mentioned in the above article but, detonation (and that was the cause) can also be caused by cross firring ignition wires or dist. cap. On a boat 99% of the time you will never hear it or feel the miss until it is to late as you found out. Sorry for your misfortune Stace, You've found the what, now you must find the why. Remember, proper diagnosis is 85% of the job.
 
I don't think she was running lean. The spark plugs all had perfect coloring, except number 1. I'm running the NGK BR6FIX Iridiums. The only thing at this point, I'm wondering bad fuel? or maybe the Thunderbolt igition module F*ed up. Like I said, she was running seamlessly right up until it happened.

Does anyone think insurance would cover this, or probably not because I have already opened my engine up?
 
I lost and engine to detonation many years ago on my 26 Sundancer. I did not hear any pinging. Pretty hard to hear pinging with the hatch down and cruising on plane. I paid someone to replace the engine with a rebuild. The 2nd engine lasted 5 hours and they would not take any responsibility for it. I bought a 3rd engine and then sold the boat. I got out of boating for a few years. I was so disgusted. Hopefully, you will have better luck.
 
I'm helping a friend with the same problem. His Thunderbolt timing advance quit advancing the timing. We are quite sure this was his bottom line problem.
 
The ping of detonation is actually the sound of the top of the pistons flexing
usually the top of the pistons will show cracks as well as the blowout
lean conditions will cause more of a melted piston
 
I feel your pain , but hey cheer up , there only v6's , and that's still better than a boat payment. you might have the perfect Lake Powell boat. Good Luck
 
Hard to believe only one was toast. Could it be a valve issue on just one cylinder? What if water was leaking in the cylinder and poped the piston. Intake water leak. Has to be something other than a lean condition. A friend of mine kept losing #8 piston due to a crack in the intake manifold dripping water into it. Maybe an air leak in the intake/gasket could cause lean in #1 also. Sorry for your troubles, Mike.
 
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