What's with this?

[gitz676]

I did a rebuild on a junkyard 360 and while breaking in the cam I notice a bad exhaust leak on the back cylinder on the right hand side. Turns out there is a hole through the head. Looks like a hole was tapped in the head and a bolt was broken off. Thinking of tying to seal it with muffler cement or JB weld. any thoughts?

 

[LongHorn]

I did a rebuild on a junkyard 360 and while breaking in the cam I notice a bad exhaust leak on the back cylinder on the right hand side. Turns out there is a hole through the head. Looks like a hole was tapped in the head and a bolt was broken off. Thinking of tying to seal it with muffler cement or JB weld. any thoughts?

You say the hole was tapped, then my best guess would be a Exhaust temp gauge.
I've never see one on a gas engine though, usually on diesels.
I would "JB weld" a bolt with the same threads in there.

 

[IOPort51]

That looks like it would be the mounting hole for the alternator, look at the front of the passenger side head and you will see the hole. It is not supposed to go all the way through but maybe it was a bad from Toledo or the bolt broke and some one drilled it out a bit too far


In my opinion the J B weld will melt and puddle up on the floor. I would have to suggest pulling the head and re drill and tap for a pipe plug rather than a bolt. If you do use a bolt it will have to have a head on it to actually seal and stay put. For a temporary fix you can use sheet rock mud. It is gypsum based and will hold up to the heat until it cracks out, i have known several guys that passed inspection with this trick.

Any way you look at it to fix it for permanent it will require pulling the head. If you had been lucky you would have put that head on the other side and mounted the alternator to it and never known the hole existed.

 

[gitz676]

That looks like it would be the mounting hole for the alternator, look at the front of the passenger side head and you will see the hole. It is not supposed to go all the way through but maybe it was a bad from Toledo or the bolt broke and some one drilled it out a bit too far


In my opinion the J B weld will melt and puddle up on the floor. I would have to suggest pulling the head and re drill and tap for a pipe plug rather than a bolt. If you do use a bolt it will have to have a head on it to actually seal and stay put. For a temporary fix you can use sheet rock mud. It is gypsum based and will hold up to the heat until it cracks out, i have known several guys that passed inspection with this trick.

Any way you look at it to fix it for permanent it will require pulling the head. If you had been lucky you would have put that head on the other side and mounted the alternator to it and never known the hole existed.

That's exactly what it was. I had a 50-50 chance of not having the problem. I cut a small access hole in the firewall and screwed in a cap screw with lock-tite. I have so many patches in the floor of the tub, another one did not matter. LOL