Exhaust leak in cooling system, power loss?

[fvigeant]

more details on head gasket leak and water jacket

OK so its confirmed, the water jacket is a mess (see pic). How can i get all this gunk out? Where and how should it exit.... what path is the water suposed to travel from the jacket cover to the head? The lower portion of the jacket cover is filled with a sediment much like black flaked off rust crust. I pulled the front and rear drain plugs and the front one is packed full. Next do i need a new cover or can i reuse the existing one if its in decent shape? I did break 3 of the 8 screws so they will need to be drilled out. Last year it seemd water was not going through the head this year i installed a new thermostat and restriction and noticed no water was going through the system. I also noticed the previous owner had the thermostat housing backwards... the WP marking WAS facing the carb and leading to the exhaust manifold while the man marking was connect to the water jacket T... I changed it back to what i thought was correct.... wp (assume that is water pump) i attached to the restriction and the jacket T while the man marking was attached to the exhaust manifold above the carb. Am I correct in my correction of the thermostat housing orientation?

As I mentioned before I have exhaust gasses exiting between the block and the head just beneith the part where my thermostat bulges out. (See picture... exhaust is escaping from the head/block seam just to the right of my thumb). My theory is the gasket on cylinder 1 is leaking significantly in this one sopt becuase I have a loss of power under load and I can see, smell, and hear the exhaust gasses exiting (sounds like a fast steam engine or rythmic pressure escaping). when the engine has been running for some time i get steam from this spot so water is somehow mixing with the exhaust on its way out. Given its mid june and I'd like to have my boat in the water without having to do a ocmplete overhaul... could I likely get away with a jb weld or epoxytouch up of the seam? The boat is a 74 catalina 27 and I'm nervous if i try to take the nuts off the studs for the header its all over and my boat yard doesn't have a crane so assuming I muster the cash to pull the engine if a stud is broken there are still barriers to getting the job done.

[fvigeant]

notice in the 5th picture above you can see a soot trail on the underside of the thermostat buldge in the head... this is where the exhaust and stem jet is escaping around cylinder 1

[Marian Claire]

The water works it way up to the head thru a series of holes. You can see them in the pics. They are all clogged with crud. The oval shapes are also cooling passages. It took a lot of poking, brushing and some drilling to get mine clear. Wish I had taken some after pics. Look at the online catalog, overhaul parts, cylinder/head/manifold for a good pic. You will need to pull the head for access. And a new gasket may correct the exhaust/steam leak.
Your cover plate does not look that bad and could probably be reused and MMI has the bolt repair kit.
I am sure the late model folks can help with the T-stat ?s.
Dan S/V Marian Claire

[keelcooler]

Exhaust and steam emitting from under the thermo housing is a sign of a blown head gasket. The head can go thin just under the thermo (see MMI tech tips).

It happened to me and required a new head. Check no1 compression. Good luck.

[roadnsky]

I also noticed the previous owner had the thermostat housing backwards... the WP marking WAS facing the carb and leading to the exhaust manifold while the man marking was connect to the water jacket T... I changed it back to what i thought was correct.... wp (assume that is water pump) i attached to the restriction and the jacket T while the man marking was attached to the exhaust manifold above the carb. Am I correct in my correction of the thermostat housing orientation?

Yes, it was backwards and yes you have it correct now.

[fvigeant]

thanks for the picture... the PO had it wrong for sure... wish me luck i am embarking on removal of my headcover with PB blaster after a conversation with Don this morning.

[roadnsky]

Also, try soaking that water jacket side plate in vinegar.
Might take a couple of days and changing the vinegar, but it may clean up good enough for you.
I decided to get a whole new plate with diverter from MMI since that is such an important component to the cooling.
You might also get some pointers reading an old thread of mine about the water jacket and flushing...

http://www.moyermarine.com//forums/showthread.php?t=3963

[fvigeant]

Thanks for the link... believe it or not i have read your prior post 2 or 3x prior. I've seen a number of people calling for a diagram of how the water flows. Do you have a link to such a diagram. Also do you have any secrets for getting the crud out... my jacket is consierdably worse than yours appears in the pictures. I didn't know water should pass between #2 and 3 becuase it was so plugged up :/

[roadnsky]

No I don't know of such a diagram.
But the flow is fairly straightforward as I understand it.
Pump - T/Diverter Cap on Water Jacket - Therm - Manifold - Exhaust.
(If you're looking for the flow INSIDE the water jackets themselves, I think that is discussed in Don's video. When I get home, I'll throw it in the DVD and check)
Have you considered getting Don's "Cooling Video"?
It's very informative and you'd get an excellent understanding of all of the components as well as the processes for keeping the passages clean.

As far as getting to that crud. I'd suggest the same formula as for the plate.
Soak for days in vinegar. Combined with poking, scraping and digging with wire brushes, screw drivers, coat hanger, etc.
Also, be sure to clean the 1/8" drains both fore and aft below the water jacket while you're at it.
You might also close her back up and do a muriatic soak and flush if you can get her closed.

I'm attaching Don's procedure for an Acid Flush in case you don't have it.
Did you say if you have the MMI Manual?
If not, you need to get that at minimum. It'll help you thru this as well as help you to get your A4 in good shape.

[fvigeant]

I do have a rebuild manual. Thanks for the PDF though. Yeah I'm looking to figure out how and where the water should flow within the water jacket. My main concern is that sediment is filling the area below the jacket cover... so if water is suposed to be moving through passages located below then i need to make sure i get every last bit of crud out because it is packed. in the lower 25% of the block

[hanleyclifford]

plugged block

As long as you have a raw water cooled system you will have trouble with sediment collecting in the water jacket. Only regular and vigorous flushes can mitigate the problem. You said your last one was in 2008. Even a FWC system can collect bits of iron and perhaps other stuff but the problem is much smaller. I noticed your fitting inside the jacket plate has no hole directing flow straight in. The fitting should have two holes; one about 3/8" directing flow aft but 45 degrees down, the second about 1/4" straight in. Remember, in speeding up flow (and thus reducing settling of sediment), each fitting and hose should be critically examined as to whether it is slowing down the flow.

[fvigeant]

I was wondering about the holes on the fitting... you are right there is only one I could find! I remembered the new covers from MMI have several holes

Should I drill the holes correct or just get a new fitting and or cover?

[hanleyclifford]

water jacket

If you are commited to your engine, for less than a hundred bucks you can get a whole new assembly from MM already drilled out. Otherwise, if you are good with a drill...but it was hard to see where the existing hole is.

[fvigeant]

When at the boat today I started scraping off the fitting and its like that second hole just dissapeared... will buy the full new assembly from MMI...

Question on the head removal I'm doing... how do you know when the head bolts are soaked enought to attempt removal? How many ft/lbs of pressure sould i be putting on the with a realistic exspectation they should budge?

I ask becuase I have been soaking away with PB Blaster and scrubbing like a mad man with a small wire brush then tapping the nuts from every direction with a small hammer trying not to hurt the threads or nuts. Also have been banging on the head itself and alt bracket to drive the oil deeper into the crevices. I have been at this for 2 days now. I was planning to go atleast another day before seriously trying to remove any of the nuts. I 100% fear breaking or having to remove a broken stud... most fears enter around drilling out becuase of clearance issues. What I can say is that the rust on and aroudn the nuts is nearly all gone due to the oil and my wire brushing. Several seem to be ready to come off but several others look tough. Any advise on how long to play the soaking game?

[hanleyclifford]

When you say you are worried about "clearance" issues, should we take that to mean access to the top of the engine for drilling and threading? If so, you need to say what type of boat you have and perhaps one of the team with a similar boat can offer some advice on that. As far as the PB blaster treatment is concerned, if you have the time and patience, more and longer is better.