Rust trail on block

[erikgreen]

Hey again all -

I'm working on my new boat's engine, trying to figure out what's wrong (first time in 20 years I've worked on any engine) and I've found a trail of rust running from the portside joint between the block and the head downward.

Would this be a symptom of a bad head gasket? I'm guessing I should go ahead and pull the head to take a look at it?

If the cylinders adjacent to it are rusty, does that mean I need a new head, or is some rust ok?

Sorry for the newb questions... I got good working with wood and fiberglass over the last few months, I just haven't done anything with engines recently

Erik

PS: I'm off to pick up a fuel changing pump, compression tester, new fuel filters, oil, and berryman's. It's going to be a fun afternoon.

 

[Reel Poor]

Re: Rust trail on block

What engine are you working on? What year, make, model, and serial number?

 

[erikgreen]

Re: Rust trail on block

Chevy 305 V8 (mercruiser 228) 1983.

Serial number is 5963789.

I'm gonna clean up my watery oil, then take and post some pics.

 

[Dakota47]

Re: Rust trail on block

Blown Head gasket. hopefully no water made it in the motor.

 

[erikgreen]

Re: Rust trail on block

Somehow, I doubt that's the case.

I pumped out all the oil (which was about half water, looked like) then put in a new oil filter and five quarts of 10W-30, plus a half can of sea foam. I disconnected the coil and turned the engine over for about 20 seconds to circulate the oil.

Then, I took some pictures - the red arrow is about where the rust is:

Port side close up:

I'm thinking from the look of this I need to pull the head, manifold, and everything attached to them on the port side and assess the situation.

Any advice/thoughts?

Erik

 

[RCSConstruction]

Re: Rust trail on block

That looks like it is right below the head and block mating surface. Seems to me you have a cracked block.
That one seems small enough to fix but that would be up to you.
Take care and good luck.


P.S.
You mention water in the oil. It may be a more complex crack than it appears.

 

[whywhyzed]

Re: Rust trail on block

the block is cracked - there's nothing to fix if your oil has water in it- it froze - need to get another block - luckily your setup uses a very common block and rotating assembly - you can either get a remanufactured marine engine, or you can get a used truck or car engine of same vintage (1970 to 1986) and swap ALL marine parts over, plus putiing a new marine camshaft and brass core plugs into the car/truck engine block- and of course a 350 is a nice upgrade for a few more HP while you are at it

 

[Coors]

Re: Rust trail on block

Chevy 305 V8 (mercruiser 228) 1983.

Serial number is 5963789.

I'm gonna clean up my watery oil, then take and post some pics.

How watery? and how much higher on the dipstick?

 

[erikgreen]

Re: Rust trail on block

Okay... so here's some more info that has me scratching my head.

I started my debugging of this engine with an oil and filter change. I was hoping the leak was a blown gasket... FYI, this engine was winterized this last year.. the guy had winterized it himself for the nine years previous, so I presume he knew what he was doing.

I put in five quarts of oil plus a half can of sea foam. Before I did this, I used a pump to remove about 2 liters of mixed oil and water via the dipstick tube into a pop bottle, so I could see it.

Once I had the oil changed, a friend came over and we talked about various things to try. One was, we wanted to run the engine for a while and see how fast water leaked around that rust trail in the pics, and see how fast water got into the (now clean) oil, before we took the engine apart.

So, we put the muffs on and started the motor. 12 minutes of idling (timed with a watch) later, we turned it off and checked the oil. It was clean. We had made sure the thermostat opened up so we got full water circulation, and I was watching the temp climb from nothing up to mid-range. Oil pressure was between 25-30 psi. The rust spot in the pics was bone dry at the end of our test! WTF?

Then we scratched our heads some and decided, ok, maybe it'll leak if we run it harder. So, we did the same thing, only this time we increased throttle to 2000 rpm slowly, over time. Total of 15 minutes of running at various speeds up to 2000. No leaking, no steam in the exhaust, nothing. Oil still perfectly clean.

So, we've made plans to take it to the lake tomorrow morning and see what happens. We'll bring oars, and stay close to shore. If it doesn't leak then, what can I try next?

It seems unlikely I could suck 2 liters of water and oil out of the oil pan and NOT have a leak??!?

Erik

 

[erikgreen]

Re: Rust trail on block

Coors - the test runs after the oil change, the oil didn't gain any volume, and had no visible water. Total of 1/2 hour or so run time, and no water in the oil.

The previous owner only got part-way through de-winterizing before giving up. I should have been able to pull another 2 liters of fluid (oil, water or both) out if it was full of oil. I dunno whether he pulled that much out or what.

One thing though, my friend took the two tubes off the flame arrestor that come from the valve covers, and we observed very small amounts of vapor coming out, that we think was water. It may have been leftover from the 2 liters I pumped out, we don't know.

Erik

 

[Coors]

Re: Rust trail on block

the block is cracked - there's nothing to fix if your oil has water in it- it froze - need to get another block - luckily your setup uses a very common block and rotating assembly - you can either get a remanufactured marine engine, or you can get a used truck or car engine of same vintage (1970 to 1986) and swap ALL marine parts over, plus putiing a new marine camshaft and brass core plugs into the car/truck engine block- and of course a 350 is a nice upgrade for a few more HP while you are at it

Darn, in automotive, blocks don't crack. In this thread there is nothing but :cracked blocks
It gets depressing.
Have we, as manly men, lost the part of our brain, that knows-
That if the anti-freeze ain't right- broke motor
that if it ain't drained correctly-broke motor
?

 

[Hook Line & Sinker]

Re: Rust trail on block

I saw a "fix" the other day in the local Marine repair shop that held long enough for the previous owner to sucker a buyer. He had exactly the same situation as you (and there was an identical crack in the same spot in the lifter valley). THe block was patched with Marine Tex or JB Weld. The new owner got about 3 hours on the engine before noticing the water rising in his bilge and the oil getting very grey with water contamination.
I don't think you will have much luck fixing the problem, but I wish you the best!

 

[erikgreen]

Re: Rust trail on block

Well, we took the boat out to the lake today. Ran like a champ. I didn't get a chance to check the oil yet, however.

On the way back from the lake, my trailer and new boat jackknifed, pushing my Silverado 1500 off the road and dumping the boat off the trailer.

No injuries, which is good, and the boat actually might be repairable, depending on how hard it took a hit on one side.

The truck is another story.. the rear axle might be bent.

But after working on one boat for four months almost every day to get it working, finding this one, and getting it going and out to the lake, driving it on plane for 2 minutes felt really damned good.

I'll start a new thread with pics of the repair if/when I manage to get the boat home.

Word to the wise - check your trailer, tires, and trailer loading before you travel. My 21 foot boat on its trailer shimmied enough side to side to blow one of my truck tires I think.

an expensive lesson.

Erik

 

[Coors]

Re: Rust trail on block

Bummer; do you have brakes on the trailer?

 

[erikgreen]

Re: Rust trail on block

No, I had thought this boat was light enough so I didn't need them legally, and I was waiting until I had some more money to try and fix the trailer up with electric brakes. It had an old surge cylinder on it, but none of the pads/drums/etc.

I "should" have been ok, but I think I didn't have enough control of the trailer.. probably my tongue weight was too low. Once it got swaying it was too far gone to stop. Even at 45 mph.

Erik

 

[Coors]

Re: Rust trail on block

Sorry. I bought a 21' with the brakes ripped out; pulled it once, and installed surge discs on it.
A whole new towing experience now, you don't even know 3300 # is behind you.
Hope all ends up fine.