Plug broke off inside cylinder

[FLOATY]

Will I damage anything by pulling the plugs and removing the cylinder block cover and gasket to remove a broken off spark plug piece. And if I do so, is there a particular order or pattern I should re-install the bolts @ 85 in lbs torque. This is on a 1989 115hp straight six Merc.

 

[jebeebe]

Re: Plug broke off inside cylinder

I don't think you would gain anything because the cover just seals around the plug hole. Taking the cover off won't bring the broken plug with it. The plug is tapped into the block houseing under the cover. I would try drilling in place, but don't drill clear through and use an easyout. Maybe that wouldn't work as it might drop a bunch of crap into the cyl. Better talk to Laddies.

 

[jason_rst]

Re: Plug broke off inside cylinder

take off the cover that the spark plug is screwed into it will make it alot easier to work with and u cant damage any pistons, then drill the plug out, u will probably need to tap a new thread in after if the plug still wont budge, i hope this helps

 

[gss036]

Re: Plug broke off inside cylinder

Soak with BLASTER PB and use a lefthand bit. Start out w/small bits and work your way up. If you try easy outs, make sure you tap them with a hammer lightly a few times to set them and may help to loosen the plug. There are couple of different types of inserts to use if you mess up the hole.
Kepp us updated on progress, there are a lot of people here to help you out.

 

[CharlieB]

Re: Plug broke off inside cylinder

That Merc doesn't have a cyl head, the cyl's are bored from the bottom, that cover is just a water jacket over the top of the block.

Be very careful as the center of the plug is going to break, bits of insulator and maybe part of the center electrode are going to fall into the cyl.

Try rigging a shop vac hose as close as possible next to your work in attempt to collect as much trash as possible.

Try a good penetrating oil like PB Blaster and thermal shocking the plug with dry ice, then heat, then dry ice again, repeat this until you tired of it. The more times the better as it tends to work the penetrant deeper into the threads.

Then try your EZ-out, you may have the best chance while the block is still warmed and the the dry ice has just cooled the plug.

Once the plug is out, DO NOT TURN the motor over until you account for all the insulator and electrode, you may have to remove the exhaust cover and vacuum the cyl and blow compressed air into the plug hole to dislodge and remove and particles.