Sheared off block drain plug

[Cool Beans]

Hey, I figured out why the stbd, rear engine mount and surrounding area is rusty. . .it isn't the water pump like I thought, it's the rear block plug drain.

Or at least I hope it is, else the block has a hole in it

The area is kinda rusty, but it looks like a round cast in boss with a dimple in it. . .under the back end of the water jacket cover.

I'm assuming that someone either tried to remove it and it sheared off and started leaking, or it has always leaked and just rotted away?

Anyways, what is the best way to fix this and what is the plug made out of?

Thanks!

[Al Schober]

Come on Cool - the plug is made out of whatever some PO installed. Should be brass - it's probably steel, rusted in place.
It was originally 1/8 NPT, so when you drill it out, work your way up in size to 21/64 then go at it with a 1/8 NPT tap. If you bugger it too badly, you'll just have to install a plug with JB Weld.

[roadnsky]

Since Al likes pics too, here's one of what he's talking about.
I'm not comfy with the 6" nipple hanging out there, so I use a brass plug.

[Al Schober]

Nice pic Jerry. Don't even see any vise-grip marks on the plug

[roadnsky]

Nice pic Jerry. Don't even see any vise-grip marks on the plug

Vise Grips?!!
Shame on you!

[Cool Beans]

Come on Cool - the plug is made out of whatever some PO installed. Should be brass - it's probably steel, rusted in place.
It was originally 1/8 NPT, so when you drill it out, work your way up in size to 21/64 then go at it with a 1/8 NPT tap. If you bugger it too badly, you'll just have to install a plug with JB Weld.

Yeah, given some of the other PO fixes I've found. . .and fixed. . .it is probably whats left of a zinced steel bolt he jammed in there

JB Weld is some nice stuff, saved my butt quite a few times

Thanks Yall!!

[sastanley]

Cool...I think with a couple of drill bits and a tap you can probably clean it up. Mine was too far gone, and I had to drill out to 1/4" NPT.

edit - here's a pic borrowed from another thread..as you can see, upping it to 1/4" makes the clearance on the alt. belt close!

I am starting to think like Jerry now...since I've converted to FWC, I don't really need the drain anymore..However, during the continual flushing process, having that 1/4" NPT (as opposed to 1/8") was kinda nice for draining the dirty block. I'll probably remove it and simply plug it once I am satisfied and done with my engine clean outs.

[Cool Beans]

Thanks for the pictures and tips! On my "to-do" list for winter. . not something I look forward to

[Cool Beans]

Update!! I went sailing yesterday, and noted the drip-drip-drip of brown water down the side of the engine block. Since I took this week off to enjoy myself fishing and sailing, my anal-retentive side decided it was a good time to fix the leak!

After pulling the alternator, I poked around to get an idea of how much plug was left in there. The screw driver went in pretty far. . .I unscrewed the front plug to see just how far it should go it. . .the plug maybe went in 1/4"



Dug around the rear drain some more. . .if I came up at an angle, I could bury the end of a coat hanger 3/4" of an inch in! And I also dug out some black crud. After poking around both holes, I fired the engine up to see if anything would flush out. From the front plug came a tiny trickle. From the rear plug. . .nothing

Think this is a good indication the bottom of my water jacket is gunked up?

LoL. . .

[roadnsky]

...After poking around both holes, I fired the engine up to see if anything would flush out. From the front plug came a tiny trickle. From the rear plug. . .nothing

Think this is a good indication the bottom of my water jacket is gunked up?

Cool-
Yes, that's a pretty good indication.
I can't recall... have you done an acid or vinegar flush before?
If so, how long ago?

If it were me, I'd do a good 24-hr vinegar soak and then get a filed down screwdriver and get the drains cleaned out.
Depending on how long the scale and junk has been there, the soaking may be all you'll actually need.

If after the soaking AND the poking... (I amuse myself ) you still have either no flow or a trickle,
I'd do yet another soak followed by a pressure flush.

[Cool Beans]

As long as it is innocent self amusement

No flushes yet. . .I always assumed I would convert to freshwater cooling sooner than later, so I kept putting it off. I plan on doing it over the winter, so hopefully this will be my first and last flush regimen

Thanks for the pictures, those are nifty flushing attachments!

[hanleyclifford]

Another block supply/drain approach.

[Van_Isle]

Hey, I figured out why the stbd, rear engine mount and surrounding area is rusty. . .it isn't the water pump like I thought, it's the rear block plug drain...

Quite funny ... my block drain just came off in my hand today. I thought it was the water pump too.

[roadnsky]

Thanks for the pictures, those are nifty flushing attachments!

All from the MMI catalog...

Product No. - CSOT_02_71

http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=CSOT&keywords=all&template=Templates/B000_storebuilder.html