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Core Plug Removal Fiasco

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Jul 5, 2016
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Location
Western New York
Hello. I'm new to this forum and to the B-Body world.

This my situation. I'm replacing leaky steel core plugs from the 440 block in my '68 Coronet. This has been a pain in the butt with the engine is still in the car. I'm using several different methods to remove them (4 out so far). Using a punch to "rotate" worked on 2 of them and self tapping screw and slide hammer on the other 1 & 1/2. While removing the 2nd plug (the one behind the starter) with the screw method , the plug buckled and the screw went into (through cylinder wall?) the block. I was using #8 Screws, so the hole hole is approx. .160". What are my are my options to fix this? Help please.

Thanks in advance ... Im a bonehead...
 
Yikes. That sounds terrible. Hopefully it would be low enough in the cylinder as to be able to be patched/repaired, without having to go thru the whole engine.
 
The block is that soft that it went into the cylinder wall? I only have scary thoughts.
 
I believe you now have a screw in your water jacket which could possibly be flushed out. If you're lucky. It could also be possible to snag that sucker with a magnetic rod.
I doubt very much you punched a hole in your cylinder wall. If you did...I'd stop spending any more time on that engine.
 
:welcome: aboard!

I just replaced one behind the starter. Removed starter, tapped lightly with screwdriver on top of plug. Bottom of plug pop out and grab it with channel locks. Replaced with a brass plug with hammer and seal seating tool.

Check for internal leak by filling your coolant with a half gallon of distilled water and check your oil.
 
Please stop using that method take a big long screw driver or long 3/8 extension bang the corner of the core plug all the way in remove with channel locks, pliers or vice grips you have probably been out there for three days they should take 3 mins ea for removal
 
Thanks for the response. My hat is off to the guys who can do this easily. The 1st picture is the passenger side with new plugs installed. Even with a clean shot at the edge of the plug they didn't want to budge or come out. That's when I used the screw/slide hammer with reasonable success on the 1st attempt.

The 2nd photo is an example of the hole and location. The hole might be .100 -.125 diameter and its located about a 1/4 of the up from the bottom as the arrow and dot indicate. I won't be able to take an actual picture on the hole until Saturday.

Is a hole in that area repairable?

IMG_1650[1].JPG hdblock-1.jpg
 
I am still unclear as to where the hole you have is. If you indeed have broken through the cylinder wall (as in you can see the piston/conrod through the hole, then prepare for bad news.

Jury is out though until you post a pic that clearly shows the damage...
 
If it indeed penetrated the cylinder to any real depth - you have a huge problem. If it only marred the surface - no big deal. But if indeed a drill bit, or tech screw actually pierced it, you can't fix it without sleeving the bore.
 
I'm unclear as to why you think you punched a hole in the cylinder wall??? I know you said you used a slide hammer, did you use it to drive the screw into the freeze plug? I wouldn't think you would be able to generate that much momentum in such a confined location...
Also trying to understand wire bottoming out @ 3/16... Can you get your finger in there and feel the cylinder wall now that the plug is out?
 
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Looks like it beveled out an area but hard to believe it penetrated the cylinder area.
 
Initially... I was using a screw gun to drive the screw through the plug. The plug must have bowed until it was touching the block. I feared the worst case scenario, punching the cylinder wall. At the time I didn't check the depth with a wire. I just quit for the day.
When I returned to the job, I inserted a wire into the screw hole and it didn't go all the way through the hole. Then I used my finger against the surface and tape measure to get an approximate depth.

image.jpeg
 
So if I understand correctly, I'm just trying to visualize, not being a smart ***..., so the plug was still in the block (bent) with a hole in the plug from the screw. The measurement is from the face of the plug into the block... Which is to the cylinder wall.
So why do you think you broke through into the cylinder wall? How long/ size screw were you driving in? Just my opinion but I've tried to drill pipe & round stock before and unless you punch it any kind of point usually deflects off of the side...
 
If I am seeing this correctly that hole is about 1/4" deep in the outer cylinder wall?

These blocks are sand casted so I guess it could happen....
 
I would install a temp. freeze plug and add water.
 
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