Topic: Sheared Plug

[sanxa_]

After a couple of days of penetrating oil application I went to remove the plugs from my 350f project only to wind up shearing a plug in the head. Of the three others, two plugs came out no problem and one with a little resistance. The plug sheared at the thread (pics to come when I get home). Is there any quick DIY way of getting this out or is it time to pay a visit to my friendly neighborhood machine shop?

[DH]

What usually happens is the threaded portion with the neg. electrode
breaks off flush with the head surface. You'll get a lot of answers/solutions. IMO is to pull the head for easier access. If you're good at drilling and tapping, have at it. Machine shop is probly best route tho.

[iron_worker]

You'll end up getting a lot of crap inside the motor if you try to drill it out which is far from ideal. If you want to risk it then go ahead but I would pull the head.

IW

[martin99]

Oh dear. I think the head will have to come off. If you attempt to drill it in situ, you may end up with swarf on the piston just waiting for an opportunity to slip down the gap between the piston and barrel or to jam a valve open. Even if you take the greatest of care, you'll never really be sure will you?

With the head off, you can drill the centre out of the plug. If you use a left hand drill you might be lucky and get it moving that way. More likely though, it will need heat, penetrating oil, heat, penetrating oil etc, heaps of patience and a good stud extractor. There are several informative videos on Youtube by the way.

[Vinhead1957]

The safest way would be to take the head off but I would explore other options. If you do use an extractor, I would put the cylinder at TDC and that would in sure that both valves are closed. It would minimize the area debris can collect and vacuum the cylinder out after extraction.

[Mo]

I had this problem from the previous owner who failed to mention it. I found it was cheaper to take the head off, and buy a replacement from ebay. Replacement costed be $50 shipped, machine shop wanted $120 to attempt the job.

[sanxa_]

Thanks all - looks like the head is coming off. Not too big a deal as it was in the plan anyway, just wanted to turn it over before engine work.

I had this problem from the previous owner who failed to mention it. I found it was cheaper to take the head off, and buy a replacement from ebay. Replacement costed be $50 shipped, machine shop wanted $120 to attempt the job.

I'll look into this. Seems there's lots of viable options on ebay for a lot less than that 120.

[DH]

As a last resort if you don't want to replace the head, you might try
somewhere that does small engine repair (lawn equip.)etc.
just a thought. Also, there are tools for this specific problem, used for late model ford trucks with the 5.4 sohc engines. Not sure if the tool is the same size as your plug, but worth asking about at an automotive machine shop. I've seen the tool work, and would make short work
out of plug removal with head removed from engine.