Oct. 1924 engine w/ Z head.
After quite a bit of fiddling around, I re-connected my carb and she started right up. But fuel leaking out of carb. Took carb off again and took it to a small engine repair shop (it's one of the Walbro carbs sold at TexasT but is more of a garden tractor carbs.) Turns out the float wasn't positioned properly so pin wasn't seating properly. Quick fix, put carb back on, no luck starting. Only change from last start was remove / replace carb after float fix.
I wonder about spark. Tried to take out #1 plug, but it won't budge. Strange because I'd put it in just a few days ago. Cinched down tight, but not impossible. I went to #2 plug, came right out, tested for spark - had spark, put it back. Where things are failing now I have no idea. But it gets worse:
I tried to take a shot at the #1 plug again. Confused as to why it was so tight. Pulled a little harder and Snapped off the plug. So now I have half a plug in my hand and half very tightly buried in the engine block. Besides needing to buy a new spark plug, my bigger problem is what has to happen to get that plug out. I assume it's going to take professional help. I hope it can be done without removing the head.
Charlie, what type plug was it? It broke off flush with the top of the threads in the head?
Autolite 3095 Take Apart. And it did break off flush with the head.
For the life of me I can't see how it got so stuck in there. I should have known better than to push harder. Maybe a little JB Blaster and overnight would have saved me a lot of time and money.
Take a hacksaw and cut the threads just to the point where it hits the thread on the head. Make three cuts and that should weaken it enough to break it free with a easy out tool. If you see it start to move be careful that you don't drop a piece in the head.
Would JB Blaster or some other anti-seize type stuff be helpful?
If I manage to get the broken piece out following directions above, would I use this part to chase the threads before re-installing spark plugs?
The threads are pipe tap so they are tapered. If you try to chase the threads be careful not to go too deep or your plugs will drop right through.
Thanks Val. You just saved me from making a big mistake and having to re-post again. If I just use the tap and go with barely any leverage, basically turn it thinking "cleaning" vs "tapping". Hit some resistance, don't try to push through it?
Take care in cleaning the threads in that aluminum head, as the material is very soft. Probably why the new steel Autolite plugs got stuck, as twisting in over tight the steel plug threads into the alum. caused the stick.
When clean, re-install the new plugs with ant-seize wiped on the plug threads. Same too is helpful with cylinder head bolt threads. Anti-seize is helpful good thread lubricant and sealer too.
Removing broken off pipe threads add an additional challenge to get out and of course you cannot afford to damage the threads at all. It will not come out with an easy-out. I usual wild a nut or bolt to the remaining threads. The added benefit is that the part shrinks when it cools and removes easily.
If you do not feel confident removing it, pull the head and have an experienced person help you with it. It should be relatively easy given the correct equipment.
The threads of the sparkplug may protrude into the combustion chamber and have carbon / soot build up on the thread causing the thread to lock up in the aluminum head when trying to unscrew the plug. I know that doesn't get the plug out but may help you understand what you are dealing with.
If the other 3 plugs are still firing, start and run the engine until it is hot. In fact you might cover the radiator to heat it up faster. Then try to remove the plug. Aluminum expands at a greater rate than steel and it should be looser after the engine is hot. In fact with any engine of any make car with aluminum heads the plugs should be removed with the engine hot if possible.
Charlie, You could try a internal pipe wrench the 3/8" one seems to fit an X plug body quite well. You could probably find them at Harbor freight or maybe TSC or even NAPA. Jim
Cheap internal pipe wrench sets are available at Home Depot.
Higher quality sets are probably available at your local plumbing supply.
I've never heard of an internal pipe wrench, but that's pretty neat. I could've used those plenty times.
Sometimes, things that break off that way will surprise you, and come out easy. Especially if you can run a heat cycle like Norman Kling mentioned. I would recommend at least trying that. After that, if the broken piece does not come easily, plan on pulling the head. Now you have a couple more options.
Able to work from both sides, and most spark plugs have a fair size hole down the middle, you should be able to put a good solid bolt through. Use the largest bolt you can fit in, plus a few lock washers, and you get something that you can put a wrench onto again.
Work from the underside of the head. That way, you turn clockwise to tighten the bolt through the broken plug remains, That same clockwise would turn the remains of the plug threads the correct direction to go on out with the taper (again, working from the bottom of the head). This method often works well, and rarely damages anything.
But, if that fails. Drill press time.
Again, work is to be done from the underside of the head, in the combustion chamber. Depending on the specifics of the plug, and where and how it broke, you may need to clean the plug up a bit (you may have already had to do this to get the bolt in for the previous effort?). Size needed of drill bits also will vary upon specifics of make and model of plug broken. Don't drill too big too fast. If the first try fails, you may end up with too little material left for a second attempt. But you want to get a good bite into the offending plug piece. As the drill cuts in, there is heat, vibration, pounding, all trying to turn and push the plug remnant out. This very often works, really well!
As a point of order; The reason you cannot work this from above the head (or with the head installed on the block) is that the normal rotation of most drills will attempt to drive the remaining threaded piece forward. Unfortunately, Forward from above the head would drive the threaded remains down into the smaller end of the tapered thread. Nope, Uh-uh, don't do it. But there is a way. Drill bits can be ordered in reverse twist. Drill motors are available that run either direction. A backwards drill bit running in reverse direction will try to turn the broken remains back out, towards you. This doesn't work as well as going forward, because some of the pressure and vibration forces are working against you going the way you want it to. But sometimes it works very well, and oh boy did it save my bacon a few times working in a blind corner inside a block.
Why one would lock up is a mystery. I was thinking at first dissimilar metals reacting to each other but it's only been a few days as you said. I'm discounting crossed threads as I believe you'd have mentioned it going in hard so I'm down to just plain old pipe thread locked. Seems to depend on what you can get into the existing hole of the broken off plug. The internal wrench is great and I've used them before. Heat is your friend. Use a propane or mapp torch to heat the area well. Both the plug remains and the surrounding head area. Just before you try your removal tool of choice spray or apply water to the plug piece. It'll cause a shock and make the piece contract a bit hopefully freeing it. Works great on NH main jets. They come right out. The thing is you must be ready to "go". That is don't allow it to cool off before trying removal. I would (if it were me) definitely try this first before head removal.
I second Wayne on removing the head first, anything dropping into the cylinder, if you tried cutting from above is going to be hard to retrieve, causing more misery down the road. Jim
The plug broke off because it was over tightened. You need to just tighten the plugs snug. You don't tighten spark plugs with anything more than a standard 3/8" ratchet, no more than 7" overall length. Put some Nickel Ease or C5A conductive anti seize compound on the threads.
Too big a job to try as a first step. As Wayne also says sometimes they come out easily with a heat cycle. Of course if you were to drop something in that couldn't be retreved with a magnet the point is moot but he's not there yet.
Rather than running the engine to warm things up you could heat the area around the broken SP w/a torch or heat gun.
If you decide to try cutting the threads as Will Copeland suggested, keep the hose end of a running vacuum cleaner next to where your cutting, to catch any cuttings or pieces and keep them from going into the cylinder.
Much appreciation for the wealth of knowledge and recommendations here. The nice thing is that I have an assortment of options starting with the least invasive and none of them seem to close out another.
I'm happy to announce that at least the threads aren't crossed. I turned all the plugs in with just my fingers before applying the socket. Certainly enough threads went in smoothly to know it's not cross threaded.
Guessing from the comments above, I'd say for sure I over-tightened the plugs using way too big a ratchet. But also, the aluminum Z head with the steel spark plug threads must be a problem.
I've picked up the "internal pipe wrench" at home depot. But I'm not going to try that alone since i'd probably just break something there. I'm going to do the heat (MaPP torch I have), spray of water and quick pull with the internal pipe wrench.
I've also learned a lot here about tightening the plugs in the first place. I thought tight was necessary. I now know that snug is a better term.
I hope my next post will be to announce success.
Pull the head
There's not a problem using steel spark plugs in an aluminum head. Every modern car is like that. It is a non issue.
Yep. Mistake wasn't steel / alum. It was way overdoing the installation and tightening it down like my kid's life depended on it. It's funny, I consider myself fairly mechanically inclined. Starting to think mechanically "declined."
I guess it's a good time to ask a small plug question. My plugs are Autolite 3095 Take Apart. I ordered the only take apart I could find which is the Champion X 25. I'm hoping that there's not a problem mixing the plugs.
My best recommendation would be that you ship your car to me and I repair it and test drive it for the next 10 years to make sure everything is OK.
You're on the right track Charlie just follow the directions concerning heating & cooling the plug before attempting to remove it. It's mechanically locked in place and if you do things right you've got a hell of a good chance of getting it out without removing the head which up to this point is totally unnecessary.
Charlie, Whatever you decide upon just make sure you don't break off the side electrode on the base of the plug it would not be healthy for your cylinder to drop it down into it. Jim
After ingesting a lot of really great commentary on this forum, removing the head is the most likely outcome of this issue. I've got a couple of fairly simple plans that are most notable by their connection to the Hippocratic Oath - First, do no harm... I am fairly confident they won't work and the head will be coming off. I've got the new copper gasket ready to go so I know this will be resolved. It also would allow a more thorough exploration of why I've seen some globules of green goo / antifreeze in the combustion chamber and oil pan.