Exhaust manifold drain plug destroyed - removal???

[DKJBama92Mariah]

Hey guys,
Here's the story. A couple of years ago, i lost one of the drain plugs to the exhaust manifold (1/2" square drive type) down in the bilge. I bought a replacement at the local boat dealer; apparently it was a cheapo. When i went to winterize the boat before going back to school this fall, the part of the plug that the ratchet fits into shattered. Therefore, the plug is stuck in the manifold with no way to get pliers onto it or anything. I drilled a hole through the center of it to get the water out and planned to handle getting it out over christmas break. Does anyone have any ideas? I considered just pulling the manifold and taking it to a machine shop and just let them handle it. I guess another option would be to drill more small holes and try to wedge a flathead screwdriver into it. I'd then use a pair of vicegrips on the screwdriver to get turn the plug. Any thoughts, comments, or experiences would be appreciated.

Thanks,
DKJ

[cwsaltare88]

DKJ,

You might try soaking any exposed threads in penetrating oil/WD-40 for a few days and tapping it lightly with a hammer. This may loosen the drain plug enough where you could use an easy-out to remove the plug. If it's like the drain plugs in my boat they are probably hard to get to, so I'm not sure if this will help much.

Another option, heat can also loosen stuborn bolts, try using a torch to heat around the plug (don't get it too hot and warp the manifold) you may be able to get it loosened enough to remove using this trick (you would have to repaint though).

Not sure this helps much but, good luck.

cw

[DKJBama92Mariah]

bump...
Its now springtime. Any new ideas???

[Salty87]

jb weld the hole you drilled and deal with it in the winter? i like it.




that's a tough one, trial and error for sure. your original plan sounded pretty good. would be too easy if that plug was plastic.

i think you're gonna be the expert when you're done. did you try drilling more holes to get the screwdriver in?

[DKJBama92Mariah]

Thanks for the reply salty. We got it out this afternoon. We drilled enough holes in it to get the blade of a sawzall in there. We then made two cuts at 90 degree angles from each other. After a few whacks with a hammer and metal chisel, the rust broke and the plug was made small enough to twist it out with the blade of a screwdriver stuck in one of the cuts made by the sawzall.

Thanks again,
DKJ

[russell C]

Thanks for the reply salty. We got it out this afternoon. We drilled enough holes in it to get the blade of a sawzall in there. We then made two cuts at 90 degree angles from each other. After a few whacks with a hammer and metal chisel, the rust broke and the plug was made small enough to twist it out with the blade of a screwdriver stuck in one of the cuts made by the sawzall.

Thanks again,
DKJ

I had the same problem with my '87 TS6M
Solved it by drilling a 14mm hole in the plug.
Used a saw blade made cuts through the plug at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock stopping short to avoid damage on the manifold thread.
Then a knock with a metal chistle collapsed the remaing body of the plug to the centre of the 14mm hole I drilled.
Worked a treat.

[CJD]

I run into this frequently when dealing with 50+ year old engines and equipment. The approach I use is to..

1) grind a flat onto the exposed portion of the plug.
2) Center punch the dead center spot on the plug on the flat ground spot.
3) Start with a small drill and work your way up to the larger size when you are just starting to reach the threads in the manifold.
4) run a tap through the hole...to clean out what is left of the plug and clean the manifold threads.

I can normally do the whole job in about 10 minutes.