Rusted/busted spark plug

[gilby246]

Long story short
88 commodore, twin Mercruiser 5.7, alpha one gen one

I have a spark plug rusted in the head that ended up breaking off when I tried to remove it(knew it was gonna happen...#3 plug) . The threads are still in the head but the porcelain came out? Currently soaking in BP blaster?..
As far as I see it, I have three options, unless someone has a better idea
1- try some heat and use a male easy out
2- Carefully drill it out in place (port side of starboard engine)
3- pull the head and drill it out/or heat and easy out

 

[Allbutwet]

Re: Rusted/busted spark plug

Did the hex nut of the plug break off or just the porcelin? If the nut is still there I'd let it soak satureted in PB blaster. Then in the morning heat it up and try again. Other wise pull the head. This way if you have to drill it out you will not risk damage to the engine. And you will be able to helicoil it if necessary.

 

[Bondo]

Re: Rusted/busted spark plug

As far as I see it, I have three options, unless someone has a better idea
1- try some heat and use a male easy out
2- Carefully drill it out in place (port side of starboard engine)
3- pull the head and drill it out/or heat and easy out

Ayuh,... I see different options,....

1,... Get it out with an Easy-out....
2,... Pull the head, 'n have a Machine Shop get it out....
3,... Replace the head....

 

[Don S]

Re: Rusted/busted spark plug

I have removed several with an easy out, I just heated it up really hot with an Oxy/Act torch first. The only thing you have to hope is that the electrode on the end of the plug doesn't break off. If it does, you will have to pull the head to get it out of there.
IF that doesn't work, Bondo lists the other to options above

 

[dccordell]

Re: Rusted/busted spark plug

I had pretty good luck with an easy-out when two of my plugs broke off like your's did. It took a good bit of force to get them to break free, almost was afraid the easy out was going to break, so you have to judge just how hard you can turn the thing. One of them didn't want to break loose at first, so I took a round chisel and lightly tapped the remaining part of the spark plug to help break the rust loose. Then the easy-out brought it right on out.

Like Don said, when you get them out, make sure the electrode is still attached. Mine just bent over as the easy out pushed it, but didn't break.

Good luck..