Removing broken spark plugs

[jcmiller]

I'm working on a Chrysler 6-cylinder flathead. Four of the spark plugs are broken due to severe corrosion of the metal portion of the plugs. I'm not sure how stuck the threads are because the plugs broke with little force applied. On two of the plugs, the ceramic portion also came off, leaving just the metal threads in the head. On the other two, the ceramic portion is still attached. Everything has been soaking for the last two weeks in PB Blaster and the ATF/acetone mixture.

I made my first attempt last night to use an easy out to extract one of the threads. I tapped the tool lightly to try to get it to seat but it would not. I am concerned that if I tap it too hard, it will break through the metal threads and damage the head or expand the metal threads making it even harder to extract. How hard can I hit the tool to get it to seat properly?

Regarding the two plugs with the ceramic still intact, should I try to get the ceramic out of the threads and proceed with the easy out, or is there another technique that can utilize the presence of the ceramic?

I bought a propane torch for this and have heated up the plugs and let them cool a few times. But I've gone pretty light with the heat to avoid damage. How much heat can I apply?

Another thought I had is to somehow create two slots in the part of the threads that protrude from the head and use a screwdriver-like tool to try to twist it out. Has anyone tried that?

Thanks.

[keiser31]

What year/size engine is the head for? It might be easier and cheaper to get another head. Just a thought since flathead six Chrysler engines are still out there.

[W_Higgins]

When something breaks on the way out, extractors are usually not the way to go for a number of reasons (some of which you've mentioned).

Don't take this wrong, but the head is off the engine, is it not? I just don't want to throw answers out there if you're trying to do this with it still installed.

Keiser's got the easiest answer. Laborwise you're looking at some work.

[Restorer32]

Unlikely that you will get the plugs out without doing considerable damage to the threads in the head but they could be helicoiled if necessary.

[jcmiller]

Thanks all. It's a 1948 250 ci motor. The head is on the engine. By way of background, I'm trying to remove the plugs in order to pour oil in the cylinders in order to determine if the engine is seized. If it is, I may not continue with this particular project as the car has other significant issues.

In response to W_Higgins, I should emphasize that the plugs broke without much force being applied so the threads may not in fact be highly seized up. The two that came out the conventional way came out pretty easily.

Jeff

[keiser31]

Is the engine still in the car? You could always try to get a chain wrench or a strap wrench to turn the engine over using the crankshaft pulley (I'll probably get some flak over that one).

Edited November 30, 2010 by keiser31 (see edit history)

[W_Higgins]

In response to W_Higgins, I should emphasize that the plugs broke without much force being applied so the threads may not in fact be highly seized up. The two that came out the conventional way came out pretty easily.

You may be right. They must have been pretty rotted from retaining water for that to happen. That said, they've also had a good long time to rust in place.

Sounds to me you're like dealing with a situation where the head will have to come off if you decide to run it, anyway. Just forgo pouring oil in the cylinders and see if it will turn over as it sits. If so, remove the head, fix your plug problem, and clean out all the crap. It sounds like at the very least it will still need a head gasket.

[jcmiller]

From what I've heard so far, I'll probably do what Walter suggests although I think I'll try to remove the ceramic because then I can get oil into the cylinders. Thanks, Jeff

[Bill Harmatuk]

Old mechanic's trick.

Heat up the area around the spark plug really hot.

Take a candle made from real bees wax and soak the threaded area with wax that is melted from the heat of the metal.

Do this several times and just gob melted wax all around the plugs in order to get the wax to leach into the threads.

Heat melt/gob wax, cool.

Do it again.

Get your easy out or wrench ready and heat again.

They should break loose.

What your trying to do is expand and contract the metal so the bees wax will make its way into the threads. Several heat cool cycles may be necessary.

Used to work at the paper mill on some really huge nuts, bolts and studs.

We had cakes of pure bees wax just for this kind of thing. First time I saw it done I thought it was a miracle.

Good luck.

Bill H

Edited December 1, 2010 by Bill Harmatuk (see edit history)

[c49er]

I have done this repair quite a few times on the MoPar flatties. I use a Oxy/Acetelene torch and heat the remains of the spark plug red hot really quickly -and insert the proper easy out and they always back right out! Always. I have done this probably 10-15 times too on core engines. Now with the ceramic still stuck in the base of the plug you probably will have to pull the head. I take it this engine has sat not running for years for the plugs to rust away that badly. If so some of the valves are probably stuck too. Thats been my experience.

[Rusty_OToole]

I've done this a few times too usually on Chev V8s. The later model ones are patsies for this because the metal of the spark plugs is paper thin. If the plugs have been in there for a few years at least one is sure to break off.

I use the type of easy out that is square with straight corners. Not the threaded kind.

Heat the metal red as C49r suggests, tap the easy out in lightly and it will unscrew. Do not drive the easy out in hard or it can wedge the broken plug end into the head.

On the ones where the ceramic is still in there. Does this mean the hex part of the plug is still on? If so heat the plug red and take it out with a socket wrench.

When the hex breaks off the ceramic should pull out because there is nothing left holding it. Try wrapping the ceramic with a rag and turning or wiggling with a pair of pliers. The trick is to work it loose without breaking it off.

[Guest Silverghost]

If all of the above suggestions fail~

Here are some last ditch ideas that have worked for Dad & I in the past~~~

In some cases an eazy-out extractor may make the situation much worse.

The spiral type easy outs tend to force the stuck spark plug thread metal outward causing threads to only get tighter~

It's like using a wedge.

The harder you turn the easy-out the tighter the threads become !

I am not a big fan of easy-outs on heavily rusted threaded parts.

I also like the tapered square easy-outs as they tend to grab more without forcing the threads outward.

When all else fails you may want to just break off the top portion of the metal on the plug after removing all of the ceramic insulator.

This will leave the threaded portion only to deal with.

With a sharp center punch try to collapse the plug's remaining threaded portion inward toward the center of the hole. This should release the male threaded portion from the cylinder head spark plug female threads.

You can also use progressivly bigger drills to thin-down the remaining plug threaded sections.

Thinner metal will bend inward more easily.

A ground-down hacksaw blade can also be used to cut the inner portion of the remaining plug's thread~

Be careful not to cut into the cylinder head's female threads.

A thread insert like Heli-Coils stated above are a good repair option if you do in fact damage the head's threaded plug ports.

There is also a complete set of inside cam-locking type pipe wrenches that a good plumbing supply may have to grab the remaining spark plug's threads from the inside.

These are costly but worth the money on very tough jobs !

Doing all this with the head still on the engine is not a very good idea~

It makes it much harder leaning over the engine .

And you WILL drop metal and ceramic chips inside the engine combustion chambers.

I would pull the cylinder head !

Good Luck !

Edited December 1, 2010 by Silverghost (see edit history)

[jcmiller]

I really appreciate everyone's advice. Can a propane torch generate the kind of heat necessary for the methods mentioned above? Is this hazardous since I already poured some oil through the two spark plugs without ceramic into the cylinders?

[Guest Jim_Edwards]

I really appreciate everyone's advice. Can a propane torch generate the kind of heat necessary for the methods mentioned above? Is this hazardous since I already poured some oil through the two spark plugs without ceramic into the cylinders?

You might want to consider a Map gas torch instead of propane if you don't have access to an Acetylene rig. In a pinch if you can find a Bernzomatic Oxygen/Propane rig it will generate enough heat to get the job done, I've successfully used one as a substitute for a cutting torch in a pinch. Just make sure to buy an extra bottle of Oxygen.

Might just be easier, and perhaps cheaper, to just drop that head off at an automotive machine shop and let them deal with it.

Jim

[Rusty_OToole]

I really appreciate everyone's advice. Can a propane torch generate the kind of heat necessary for the methods mentioned above? Is this hazardous since I already poured some oil through the two spark plugs without ceramic into the cylinders?

A propane torch WILL NOT give enough heat. If you do not have access to an acetylene torch, take the car or just the head to a garage. They can take the plugs out in a few minutes. For this method to work you must heat the plug quickly without heating the head too much. It is the heat expansion that loosens the threads.

It is not dangerous to heat the head. Any excess oil should be wiped up off the head but a little oil is not dangerous.

At this point I would seriously consider removing the head. If the plugs are that rusty it is likely the valves are stuck and at least one cylinder is rusty. Any cylinder that had the intake valve open while the engine sat.

It would cost you a head gasket but at least you would know what was inside the engine.

Can you turn the engine by hand? If it was stuck I would definitely take off the head.

[Spitfire8]

If the ceramic has broken enough to allow you to squirt oil into the cylinders, it's likely some ceramic particles have also dropped into the cylinders. For me, that's a "head-off" situation.

Once the head's off:

1) Heat the head surrounding the plug using an oxy-acetylene torch if possible.

2) Use a wet rag or a spritz bottle to apply water to just the plug. Immediately use your removal tool. The idea is to expand the head, shrink the plug and quickly use the removal tool before the temperatures equalize.

[jcmiller]

I thought I'd give a quick update. I was able to remove the ceramic from all four of the stuck plugs without breaking any ceramic. I then poured a bit of oil in each cylinder and let it sit for a few days while I removed the radiator. Last night I tried turning the crankshaft pulley by hand but was unable to do so. I think I'm going to buy a large socket and try to turn it with a socket set. Do I need to be careful to only turn it whatever direction it normally turns?

Also, a lot of the oil I put in the cylinders ended up on the garage floor. It looks like it dripped out the exhaust. Is that normal? I guess that oil probably leaked out the exhaust valve, into the exhaust pipe, and out a small hole.

[W_Higgins]

Worst that will happen if you turn in the direction opposite of rotation is the bolt may come out (or with the luck you've had with your plugs -- snap off!).

If your plugs are situated over your valves, like on many flatheads, you might have just poured your oil right down an open exhaust valve. Get an oil can that you can squirt toward the cylinder.

[Bhigdog]

Pull the damn head already!.............Bob

[jcmiller]

Pull the damn head already!.............Bob

Don't worry Bob. I will if I can get it to turn manually first. If I can't do that I might just cut my losses and get rid of the car.

[Guest Jim_Edwards]

Don't worry Bob. I will if I can get it to turn manually first. If I can't do that I might just cut my losses and get rid of the car.

Try more or less a rocking motion with the socket and cheater bar routine. What you are dealing with is a rust ridge on all cylinders. While you may get it loose and get the crank to rotate you'll still have a pitted area in the cylinder walls. Meaning you might as well just pull the engine and take it to a machine shop and be done with it.

Jim

[c49er]

If the engine is that stuck- time for a complete rebuild to do it right! BTW to force a engine to turn over use the flywheel teeth with a large screw driver to turn it over, way more leverage there that the crank nut. Looks like the rings/pistons are rusty as are the valves-way bad!

[jcmiller]

If the engine is that stuck- time for a complete rebuild to do it right! BTW to force a engine to turn over use the flywheel teeth with a large screw driver to turn it over, way more leverage there that the crank nut. Looks like the rings/pistons are rusty as are the valves-way bad!

How do we know how stuck it is at this point? Should I have been able to easily turn it over by hand just by holding onto the pulley? I don't think I was able to apply much force that way. There are quite a few stories on this website about people unsticking engines without a complete rebuild. I'm not saying I won't have to do that, but I don't think it's come to that stage just yet.

I'll bet Rusty O'Toole would have this engine eating out of his hand in less than a day. http://forums.aaca.org/f169/old-engine-start-up-274491.html

[Rusty_OToole]

If the engine is not stuck you should be able to turn it over with your hands especially with the plugs out and some oil down the plug holes. But then, the plugs should have come out too.

You may have one of those engines that is too far gone to revive without taking off the head.

[Guest Jim_Edwards]

If the engine is not stuck you should be able to turn it over with your hands especially with the plugs out and some oil down the plug holes. But then, the plugs should have come out too.

You may have one of those engines that is too far gone to revive without taking off the head.

Or pulling the engine, removing the head, and crank then beating the pistons out of the bores with a block of wood and a 3 lb. sledge hammer. At this stage it's time to drop the oil pan to see just how much moisture has been in the thing. No point in beating a dead horse and this one is beginning to have all the characteristics of a dead horse. :eek:

Jim

[Bhigdog]

In the time the O.P. spent screwing around here he could have pulled the head and made a reasonable asessment of the situation.............Bob

[Guest Jim_Edwards]

In the time the O.P. spent screwing around here he could have pulled the head and made a reasonable asessment of the situation.............Bob

Be nice Bob, remember that first car that didn't run or run well?

I doubt if there is a darn one of us that with our first vintage car didn't focus on trying to bring that engine back to life. We all want to hear that engine run regardless of the fact the brakes don't work, the seats have been home to God knows what for years, and the rust out in the finders continues to get worse just sitting there.

Now after doing a few cars, we know the engine is going to have to come out anyway when doing a proper repaint, so why bother trying to get the damn thing to run. It's old used and probably needs a re-build anyway, even if it runs. Over the years we have learned from banging our heads against the wall, and from many years in this hobby I know that banging one's head against the wall apparently comes with that first car.

Jim

[Bhigdog]

You are right, of course, Jim. My apologies if I seem a bit short from time to time. On the other hand it's some times a bit frustrating when many folks take the time to share their knowledge only to get ignored.

So...........JUST PULL THE DAMN HEAD!..........Bob

[jazzer3]

Six years ago I bought a 50 New Yorker that sat outside and not run in 25 years. I filled the engine through the carb and oil fill with a kerosene, auto trans fluid, and blaster concoction and let it sit about ten days then tried to turn it over. not a problem, soon got it running on an auxilary gas tank with only one sticking valve which got freed up with a screwdriver while it was running. the engine sounded like a well built sewing machine and behind the valve covers it was like new. I have put 7000 miles on it since the Spring of 2008 and it runs good.

Two years later I bought a 48 New Yorker that was last registered in PA in 1965 and must have been indoors most of the time between 1965 and 2006. There is absolutly no rust through anywhere on this car and the interior is really nice. I filled this engine with a lubricating cocktail and let it sit for a year, no dice, I had to pull the main caps and rod caps and lift the crank and fluid coupling out together in order to remove the coupling from the crankshaft. The top of the oil pickup was rusted through and the bottom of the dipstick was rusted off. The car received a new engine.

It all depends

Jay

[jcmiller]

You are right, of course, Jim. My apologies if I seem a bit short from time to time. On the other hand it's some times a bit frustrating when many folks take the time to share their knowledge only to get ignored.

So...........JUST PULL THE DAMN HEAD!..........Bob

Sorry you feel ignored, Bob. Everything I've done has been based on someone's advice along with some research. I can't follow everyone's advice at the same time because it often conflicts. If I pull the head, which I am inclined to do, I'll be "ignoring" Jim's advice which is to stop fiddling with the engine and deal with rust. I think I took reasonable steps to determine that it is at least somewhat seized. Keep in mind my original purpose - to determine whether I should even keep the car. That being said, I really appreciate everyone's willingness to chime in with ideas, even if don't follow every single one.

[Bhigdog]

Of course you are also correct. I don't feel ignored I just wish you would do something agressive. The suspense is killing me.......................Bob

[c49er]

I've done lots of parts/junk car engine starts- 1st make sure cables and starter are there. Pull plugs dump oil down cylinders. Install strong 6 volt or 12 volt even better for use on a parts car, if no key hot wire starter-if starter just clunks with a thud-engine is severely stuck-go no further with trying to get it to run. Way too much trouble. If it does turn over freely do compression test-they all need to be even and close to at least 100lbs for it to sart and run decent, then continue with your plan to get it to run.

[Guest Albert]

have been lucky with pouring a mix of diesel and auto tranni fluid down the plug holes, to free up the motor,,, had a Packard that sat 40 years, and got it to turn, still tore the motor down to a bare block and rebuilt it, but i got all the pistons out by hand, and all the rings where free, but it sat for 3 months with diesel and atf on the pistons,, I also broke a bunch of plugs off too, as the hex twisted off, leaving just the threads left in the head,, i Heated the threads only so they where red hot,, this caused the rust to break its bonds, as well as to expand the threads into the head to the point that the threads can not expand any more and the threads start to collasp, then you let it cool on its own , and the threads will now be smaller than the threaded part of the head, and it unscrews very easy with just light pressure from an easy out,, dont have to tap it in, you may have to knock the bottom electrode out of the way a bit thought if the easy out bottoms out on that..

[jcmiller]

Of course you are also correct. I don't feel ignored I just wish you would do something agressive. The suspense is killing me.......................Bob

Merry Christmas Bob. My brother-in-law helped me lift the head off last night. I don't have anything to compare it to, but it looks much better inside than I expected. It looks like a couple of valves got hit the worst.

[keiser31]

Wow! Nice and clean!

[Guest Jim_Edwards]

Wow! Nice and clean!

Can we say clean but not without issues? It does appear the cylinder bores are in good shape, but there are seven valves that look as if they have issues, two that look as if they could be 100% stuck and the other five others possibly burned and maybe stuck. One looks as though it might have been sucking water from someplace for a while before it was parked, as does the piston in the adjacent bore. All and all it doesn't appear there are major, major issues, though I say that with reservation not knowing what the crankshaft looks like. A valve job, including a couple of replacements, and possibly one new piston is all I can see now. Hopefully, the crank, main bearings, and rod bearings are all good to go.

Jim

[Bhigdog]

Merry Christmas Bob. My brother-in-law helped me lift the head off last night. I don't have anything to compare it to, but it looks much better inside than I expected. It looks like a couple of valves got hit the worst.

A very Merry Christmas to you. Excellant news. Now you can soak the bores/ rings properly. Maybe spritz the valve stems too. Hopefully in time a little pry bar work on the ring gear will free it up and you can get a good assesment of whats needed. Right now I'd be encouraged.........................Bob

[Guest maynard]

I like to uue a left hand drill bit. this heats up the metal part of the plug & they sometimes come out very easy. If not finish by using the square exstractor.

[jcmiller]

I finally got this thing to turn over.

I wrapped some tubular webbing around the pulley. By pulling on the webbing while a helper turned the pulley by hand we got it to move. It was great to see those pistons moving finally, although I don't think that all the valves are moving properly yet.

[Guest KINGOWOOD]

I have done this repair quite a few times on the MoPar flatties. I use a Oxy/Acetelene torch and heat the remains of the spark plug red hot really quickly -and insert the proper easy out and they always back right out! Always. I have done this probably 10-15 times too on core engines. Now with the ceramic still stuck in the base of the plug you probably will have to pull the head. I take it this engine has sat not running for years for the plugs to rust away that badly. If so some of the valves are probably stuck too. Thats been my experience.

Worked perfect, first try. It was on boat, 4 cylinder Ford. Phewwww. Thanks were in order so thanks!