Found a crack...

R

roy

.
Feb 1, 2009
186
2 270 soldiers point
Well, well. Looks like i'm gettin it yet again.

Found a crack on my MD6A block. On the supposedly perfectly maintained engine. It looks like it is on one of the water cooling chanels. It no longer leaks, as it looks like it has filled up with salt.

The thing I still don't understand is that I have good compression, good timing, rebuilt injectors, and good fuel delivery. Shouldn't the crack be doing something bad that can be measured? Dispite the crack, if all specs are in line, shouldn't the motor work somehow?

The engine smokes light smoke all the time and black if you ask anything of the engine (with black chary lily pads behind the stern). The oil is black, probably with the unburnt char too.

Somebody mentioned that you can have the timing 180 degrees out and the marks will line up.

The last thing I can try is to re-bleed the system and maybe replace all fuel hoses. Maybe an air leak somewhere?

And I had a survey done. Only to find out that you need a team of surveyors to buy one lousy 27 foot fiberglass boat. I guess it's like rocket science. I need a toilet surveyor, a sail surveyor, a wire surveyor, a keel surveyor, a tiller surveyor...

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W

wxt8981

.
Oct 31, 2019
562
Looks like your engine wasn't drained for winter storage.
If you have a crack in the engine block- say "good Bye" to
your engine and get a new one. But if your boat is
(again)in a climat where it freezes, make sure you drain
all water before winter storage.
Wilhelm, V-257
 
G

groundhogyh

.
May 30, 2006
1,075
My father in-law loves that jb weld stuff. br
He mentioned that you might be able to really weld the crack shut.brbr

??Could water be getting into the cylinder and the compression still be high? I purchased Nigle Caldwell's (sp?) book and it says that white smoke can be water vapor.brbr

Thanks,
gh
brbr
 
W

wxt8981

.
Oct 31, 2019
562
The compression can still be high (for a time), but if you
get salt water into the engine, it will eat up everything
inside, including the bearings. Check the oil- if there's
any water in it, you've got a problem.
Wilhelm, V-257
 
G

groundhogyh

.
May 30, 2006
1,075
No, there is no water in the oil (it's just black in color). And this crack has been there for quite awhile by the looks of it. br
gh brbr
 
G

groundhogyh

.
May 30, 2006
1,075
That's a good point Wilhelm. If the light colored smoke was caused by water then some of it should eventually end up in the oil because it would get by the rings. So does that prove that the crack is only to the outside of the engine? brbr
gh
 
T

trevy_kins

.
Oct 31, 2019
230
Where is the crack exactly. I thought the frost plugs were supposed to
pop if the water froze in the block. Perhaps it's a superficial crack.
Here's hoping. Trev V2915
 
G

groundhogyh

.
May 30, 2006
1,075
Well, if you are looking from the flywheel side, it is on the left corner of the block just below the interface of the head and block. brbr

I'm going to post a picture of it. Go look in the photo album of "Good Things".brbr

Does the MD6A have those plugs? I noticed some pics of them in the new Diesel book I bought, but the pictures were of larger volvo engines.brbr

Please tell me it's a superficial crack! brbr
 
W

wxt8981

.
Oct 31, 2019
562
Any water left in an engine can and will crack the block,
it's always a good idea to drain all water (if there is a
drain plug), or run the engine with anti-freeze (but make
sure you see the yellow stuff come out at the exhaust and
turn off the engine when the suction hose still is filled
with anti-freeze). There also should be a drain plug in the
bilge; take that one out as well. And if you ever get a
crack in the engine block, you're better of getting a new
engine. Sorry!
Wilhelm, V-257
 
G

groundhogyh

.
May 30, 2006
1,075
So the drain plug in the bilge. I take the wooden floor covers off and pull a plug in there? This is for when you put the boat on dry land, right?
gh
 
W

wxt8981

.
Oct 31, 2019
562
once you put the boat on the dry, you should see the plug
outside (there may be anti-fouling paint over it, but you
should notice where the plug is) Unscrew it and put it back
in when the boat is launched again (don't loose the
plug....)
Wilhelm, V-257
 
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