Expensive mistakes, and what the heck is this thing?

[sail_4_me]

Today I pulled the boat cover off, to get ready for the work on my engine mounts. I discovered that I had neglected to drain the engine intake water strainer. The result is that the cylinder cracked, and I'm now ordering a replacement. As pennance, I'm posting the picture. Hopefully someone will learn and remember to add a check box for this during their own winter prep.

An additional thing I found was a nickel sized circle of steel, that looks like it was sealed on with some kind of hard glue. I don't think the glue is epoxy because its slightly flexible. It's also painted the same color as the engine, so I'm nervous as to where it came from!

It was found under the oil pan, up towards the transmission. I looked around but cannot locate where it came from. I thought I would post here in case any of you fine gents have a clue where this came from. The engine is a Yanmar 3QM30F.

 

[guidera48]

Block Freeze Plug???

 

[sandpiper10471]

Frost plug is my first thought too. Perhaps try posting this on the new engines forum, too. So sorry for all your angst. These discoveries are almost enough to make you wish winter were still going strong!

 

[Ed Schenck]

Your engine is an 'F' meaning fresh-water cooled, right? So the engine is protected with regular anti-freeze. If that anti-freeze level got too low it could pop a freeze plug. If that is what happened there is an easy test. Just try filling the engine water using a 50-50 mix. If it was a freeze plug the water will run out onto the engine pan. I suggest a 50-50 anti-freeze just in case it is not going to leak. You don't want to add just plain water.

As for your strainer I wonder how you winterize. My strainer is full of the pink stuff. I winterize the engine by removing the hose at the seacock, add an extension, and put it in the bucket full of pink stuff. I generally use three gallons and make sure I see it at the exhaust outlet. So there is anti-freeze through the whole system including the strainer.

 

[Rich Stidger]

I certainly looks like a freeze plug with the hammering marks around the edge from when it was installed. I hope I'm wrong because that is not a good sign at all. It suggests that the block itself did not have adequate antifreeze in it over the winter.

 

[s sauer]

I had previously used the 'pink stuff' in the head and above the overboard discharge gate valves (maynyears ago changed to seacocks and the -60 to -100 degree antifreeze because I found the 'pink stuff' frozen to a popsickle consistency. Fortunately, I've always used -100 degree antifreeze in the engine assuming it was mixing with the seawater as it went thru during winterizing. The alternative is a complete drain down.

 

[guidera48]

On second thought, It does not look like a regular freeze plug. They usually are not flat and have a shoulder that actually fits the block. They are easely replaced with a plug driver or large socket used as a driver.
If the plug let go, you would have a mess in the bilge and you would know it.
You may need a flashlight and a mirror to find the location with the missing paint.
Jose

 

[Rich Stidger]

I recant my reply.....

I take it back from my post #5 reply. I agree with Jose above, it is not a freeze plug. I think it is a core plug. Now that I think about it more, I have installed these core plugs in carburetors and other machined castings.

See the link below for a description and picture.

http://mgaguru.com/mgtech/cooling/cool_105.htm

 

[Ed Schenck]

Interesting theory. Over on the Torresen site a search for "core plug" only turns up Volvo and Westerbeke. But they are a major Yanmar dealer.

 

[kloudie1]

Interesting because it was obviously sealed from the outside and painted over.; factory, probably.. May be up under the exhaust manifold area either on the manifold bottom or on the block just below.. As Jose says, a mirror will be useful if you want to find it before water is running out .. I would guess that it is in the exhaust manifold casting somewhere since the raw water strainer broke.. Ya prolly didn't have enough antifreeze in the manifold/heatex either. If you maesure the size or carry the old plug to an engine rebuild place, they can probably match it for you. The new one will have a considerable "dish" (concavity) in it .. ya put it in the hole domed side out, with some of Mainsail's super seal (not the buty, the putty that he is using on exhaust l) around the hole in the block, and hammer the center flat to expand it, as Rich's link shows. It won't have the deep skirts on it, is the only difference.
Looking at the last picture, it looks like there is a pinhole corroded thru the plug in at least one spot. The sealant may have been overlaid by a previous owner to stop the drip from the pinhole.. The new plug should not require an overlay.

 

[sandpiper10471]

Sail-for-me - any word on that "what the heck is this thing" item?

 

[sail_4_me]

that sinking feeling

Looks like it is a freeze plug. What started out as work to change motor mounts, is now:

-move the boat to the shop
-pull the engine
-repair popped freeze plug, pressure test
-test water pump, cooling system
-check stuffing box and hose
-change motor mounts, do initial alignment ( and again when in water ).

And seeing as the engine is out I've added these jobs:
-reinforce the engine room walls, seal the port wall to reduce noise and smell in the aft berth
-replace engine room insulation ( 28 years old, falling apart ) ( my job)
-replace hot water heater ( 28 years old.... )
-replace throttle and transmission cables.
-add racor fuel filter

And I may add a LED ceiling light just for fun.

The mechanic thinks this is the 2nd time this freeze plug came out, as the epoxy is not a factory job ( the hammer marks on the plug also gives it away ).

They've moved the boat yesterday, and today we have 15cm of snow (I removed the cover, sigh), and expect to pull the engine ASAP. They will have the motor all fixed up in about a week.

I think I will need a month to 6 weeks to get all the extra work done, with a mid-May splash.

I suppose this was inevitable. All this stuff was on my list just waiting for the initial push. I remember reading something about how small errors in judgement can create an 'event cascade'. I'm glad this one is on land!

-Colin-

 

[Rich Stidger]

Colin,

So this thing really was a frost plug? That was my first thought but then I realized that frost plugs usually have sides. Maybe the original came out and the PO put in a flat disk??

Anyway, why does the engine need to be pulled just to replace a plug? Is the access so bad that there is no other choice? Sorry to hear this; an engine pull and replace adds a big step in effort and cost.

 

[Scott]

I agree with Rich. If it was a freeze plug, it did its job. Why not replace it, fill the engine with anti-freeze. If there are no leaks, start it.

 

[sail_4_me]

Hi Rich, its not just the plug, but its also the pressure test, and mainly the engine mounts. And, there is a square plate on the back of the engine that leaks coolant, that I want fixed permanently. Not a lot of room for a lot of work that needs to be done right.

 

[Ed Schenck]

So that is what a real 'F' engine looks like. All the QM's I had seen were, like my 2QM20, modified for fresh water cooling. But yours has a real factory heat exchanger. It gives you much better access to the engine.

So do you know what happened with your winterizing that you cracked the strainer and blew a freeze plug?

 

[sail_4_me]

Update on the Engine Repairs

Hi, it's been a while.

I've pretty much done all that was on the list:
-new Seaward 6 gallon water heater ( with winterizing bypass valve )
-moved muffler closer to engine
-new motor mounts ( increased from 150 lb. -> 200 lb. rated mounts. My engine weighs 400 lbs.... )
-new engine room insulation
-new throttle and transmission cables
-new racor filter
-new stuffing box hose and packing
-new fresh water strainer
-cutlass bearing

Looks like I had a broken rear-left mount too ( yet another source of noise! )

The insulation came off with one hand, and it was falling apart. The new stuff is 3-layer, and is glued and screwed on. Added silver foil tape on several exposed edges.

I added a bypass valve for the water heater. Next year I just turn the valve and empty the tank. That should save a bottle or two of antifreeze.

Last picture is of the installed engine, minus the Racor.
Enjoy the pics.

 

[sail_4_me]

So, I've finished the engine room insulation, all glued and screwed. I also cleaned up the rad hoses.

I replaced the shaft zinc with a magnesium anode ( fresh water boat ). I never realized this thing was not doing its job until I discussed with the mechanic. Likely my prop has been taking a bit more sacrifice than it should have, but I can't tell the difference. Also, I rewired the boat last year, and I didn't see any difference ( no rotted thru-hulls, prop etc. ). Looks like I'm (slightly) lucky this time.

I will be adding a coolant overflow hose at the top of the coolant tank. For some reason this was never on the engine. Seems to me this should connect to a coolant reservoir somewhere....

Last thing I did was to secure the coolant lines to the water heater and tie-wrap the throttle/tranny cables.


Pictures added to show off my insulation skills, and perhaps give others some ideas.

 

[Ed Schenck]

Very nice results. One major project down and ?? to go.

 

[guidera48]

sail_4_me :

I am olso changing my insulation. Unfortunately, my engine still in place and it's a lot harder to replace. The existing insulation was loose and nasty. As a matter of fact, the boat smells a lot better since I removed it. I was going to add foil to the existing foam but it is nasty and smells like diesel. I will use them as patterns only.

Can you tell me what you ended up using as insulation. It looks like automotive firewall peel & stick noise/heat insulation.

I see you also have a helper lurking on the companionway. Mine is still in training. He still confuses SAE wrenches and metric wrenches but he is a great with security detail.