Removing stuck sparkplug from aluminum head (NGC)

[Antietam Classic Cycle]

I'm *trying* to change the plugs in my mom's Dodge Ram 50 (Mitsubishi) pick-up with 2.6 liter engine. Previous to this, my brother was responsible for doing the maintenance on it, but since he's moved to Oregon, it's all down to me now. I've managed to get three out (1, 2 and 4) but #3 is stuck big time. 1 and 4 came out easily since a cam cover leak has kept them well protected from corrosion.  2 came out with liberal application of penetrant, turning it back and forth, slowly threading it out for 1/2 hour and even then using more force than I was comfortable with on a breaker bar, no damage to the threads though. Tried the same procedure with 3 and can't get more than 1/4 turn back and forth rotation.

Googled it a bit and came up with nothing any better. Thought I'd ask youse guys. Any tricks/tips that have been useful for you in the same situation?

[Mike Tashjian]

If the plug is still working I would probably leave it. With that slight movement I might try to get a penetrating fluid in there and wait a bit. Too much work when the plugs break off. Try again in the Fall. Mike

[ITSec]

Short of removing the head and doing it on the bench (a machine shop exercise), the best I can suggest is that you continue patiently as you have done so far - oil/penetrant, time, and gradually working it. Heating the head is always helpful given the expansion difference. If it comes to it, removing the head allows all this to be done more easily with less risk of damaging anything. You know this, but it's here for reference 

One trick I've seen used is to set an impact wrench on a low force in reverse (i.e., back-out) and just let it steadily hammer away at the resistance. The low force setting should (and I say should, not will, so use with caution at your own risk) allow impact to be transferred to the threads without breaking the collar nut away from the threaded body that's in the hole. A mechanic/machinist friend of mine did this to an engine of mine some years ago; it worked then, but who knows...?

If you are going to do this, you might check using a vise and one of the plugs you already removed as a sacrificial test to see how much force you can or should use.

[Dilliw]

I watched a guy use carb cleaner on a Ford Triton that I had.  Turned them just a bit, poured it in, and then went at them the next day.  Expensive spark plug change.

[Demar]

I've had good luck using Kroil to loosen rusted bolts. It penetrates very well.

http://www.kanolabs.com/msn/

[vintage53]

Hello Charlie

I would wait on the Penetration oil, for a few days.   

Quick thought!  I have never tried this, BUT If heat is applied to the Aluminum head, will it not expand faster than the Steel Plug.

 

[ITSec]

I've had good luck using Kroil to loosen rusted bolts. It penetrates very well.

http://www.kanolabs.com/msn/

The guys over on the CarTalk discussion mentioned this, although some also suggested that B'laster PB is more effective. At NASIOC (a Subaru forum I sometimes hang out in) B'laster PB is a hands-down favorite. It has the advantage of wider distributions, so you're more likely to be able to find it nearby (some WalMarts and auto chains have it).

http://blastercorp.com/PB-Blaster-Penetrant-remove-stuck-parts-spray

[clubman]

Just dealt with this on a R100S that was parked in 1985 and I am trying to get running for a friend of mine. Left plug came out with some difficulty but right was hopelessly frozen. Penetrating fluids are are complete waste of time with cadmium threads that have been stuck to sand cast aluminum threads for 36 years. My last chance approach was to heat the area as much as I could without melting something (MAPP gas hand torches work good for this) and then hitting it with my impact on reduced pressure. It worked and there was no appreciable thread damage. I was going to pull the heads anyway, so if the thread blew up a Helicoil is no big deal. A head in a car that you aren't planning on removing may be something different. Good luck 

[Lannis]

If you're trying various witches brews over a course of time, the old homemade standby of 1/2 acetone- 1/2 ATF has always worked best for me.   Liquid Wrench, Kroil, and PB Blaster all have their advocates.   

One of the four is bound to be better on the specific situation of coarse steel threads into aluminum .... might be worth a search.   Different than steel-on-steel ...

Lannis

[pat80flh]

Brake fluid also works well as a penetrating oil. back it off pour some in, let it sit overnight.

[Antietam Classic Cycle]

If the plug is still working I would probably leave it. With that slight movement I might try to get a penetrating fluid in there and wait a bit. Too much work when the plugs break off. Try again in the Fall. Mike

That's just it - it's fouled, causing a misfire. Tried last Fall and Winter and Spring...

Now my brother informs me that #3 is "the one with the insert". Oh boy. That just moves this into a whole another dimension.  He suggested heating the plug and pouring melted wax around it!

[Triple Jim]

As vintage53 and clubman said, heat should help if you can get it reasonably hot.  The trouble is that a big chunk of aluminum is about impossible to heat locally, since it conducts heat so fast.  By running the engine, you should be able to get it well above 212F.

Aluminum expands about 13 microinches/inch per degreeF, and steel about 8, so you get a net gain of 5 microinches/inch per degree F.  If the thread diameter is about 1/2 an inch, the  clearance will grow about 2.5 microinches per degreeF.  Assuming you can get it to 240F from 80F, that's 160F rise, or 400 microinches of extra clearance, which is nearly 1/2 a thousandth and definitely worth doing.

[Antietam Classic Cycle]

As vintage53 and clubman said, heat should help if you can get it reasonably hot.  The trouble is that a big chunk of aluminum is about impossible to heat locally, since it conducts heat so fast.  By running the engine, you should be able to get it well above 212F.

Aluminum expands about 13 microinches/inch per degreeF, and steel about 8, so you get a net gain of 5 microinches/inch per degree F.  If the thread diameter is about 1/2 an inch, the  clearance will grow about 2.5 microinches per degreeF.  Assuming you can get it to 240F from 80F, that's 160F rise, or 400 microinches of extra clearance, which is nearly 1/2 a thousandth and definitely worth doing.

I'v tried doing this job several times as noted above. Fall, dead of Winter, Spring. Engine cold, warm and hot. The only difference with a hot engine was that #2 finally came out, #3 is still firmly stuck in the insert my brother installed (see edited previous post). 

[Triple Jim]

The only difference with a hot engine was that #2 finally came out...

There you go... my suggestion retroactively helped you get #2 out.   

[Sasquatch Jim]

  If the plug is failing to fire, running the engine may not heat that particular plug area enough.

[Groover]

I'd trade the truck in 

What's the insert for? Is that the old-school brass insert/spacer trick used on cylinders burning oil?


Edit: Truck, not car

[pat80flh]

Is your brother a decent wrench? If a thread repair has already been done, you might as well put a half inch breaker bar on it and give it all you got. At worst the insert will come out with the plug, hopefully the head is not already fubar.  most of those insert kits came with a tool to swage them in the head, if the insert comes out clean you may be able to put another one in.

[Triple Jim]

  If the plug is failing to fire, running the engine may not heat that particular plug area enough.

As I said, you're not going to locally heat or not heat a huge chunk aluminum.  On top of that, you'll have 240 degree water circulating through the water jacket anyway.

[Antietam Classic Cycle]

I'd trade the truck in 

What's the insert for? Is that the old-school brass insert/spacer trick used on cylinders burning oil?


Edit: Truck, not car

I've offered to buy her another small, used truck/car, but she "likes this one too much" so I attempt to keep it running until she finally stops driving.

Apparently the plug hole stripped once before and my brother installed a thread repair insert. His latest email response tells me that the insert came out with the plug last time. 

I think mom is still using the Winter starting routine (engine is carbureted) and is simply flooding it. I did an "Italian tune-up"  and the stuck plug is firing more often now, but idle is still uneven.

[pat80flh]

Consider the possibility of a vacuum leak causing high temps in #3, or a leaky exhaust valve.  Repeat thread failures makes me a little suspicious.

[bmc5733946]

Charlie, My suggestion will sound pretty weird and a little violent.  Run the cylinder to top dead center, (check firing order, run opposite cylinder in firing order to top exhaust), break off ceramic, break the rest of the ceramic into the cylinder with a punch.  Use compressed air and shop vac to remove debris.  Drill the rest of the plug out and possibly the insert depending what type.  Use Time-sert brand insert if possible installed following Time-sert directions.  All of this is a lot of work but as I remember those engines are pretty accessible in the chassis, of course having the head off is a lot more work and then of course you will discover all the bad stuff that has been hiding and have to fix that too.  Check length of plug thread against insert and specs for that engine, over/under-length plugs have long been a problem with carbon deposits and corrosion/erosion of plug material inside the combustion chamber.

 http://www.timesert.com/html/sparkplug.html

Brian

[John A]

The melted wax works well if you get the head heated up. Be advised if it doesn't work, and you want to go back to penetrating oil, you have to get it hot enough to disperse the wax or it blocks the oil.

[Green1]

As a last resort in the past I have removed the porcelain from the plug ,ground down the back edge of a hacksaw blade until it fit where the porcelain was and cut two slots by hand opposite in the threaded part of the plug and removed it in two pieces with a pick,ran a tap through the threads to clean them up and all sealed ok,the insert may make that impossible though 

[apex1397]

 http://www.ryderfleetproducts.com/ryder/af/ryder/core/content/product/srm/oid/291847/erm/productDetail.do?utm_source=googlebase&utm_medium=search&utm_campaign=product&gclid=CIja8qKA480CFcYehgodm_ML9A 


crc freeze spray

I have used this freeze spray before with penetrating oil.

[chuck peterson]

An axe? Just channel all your frustration and hack it out....

[boatdetective]

It seems to me that after all this time spent beating away at it- you simply could have removed the head.

[Rough Edge racing]

   Been there...If the plug loosens a 1/4 turn and locks up it's likely the threads are galled.......Don't heat the head, head the metal base of the plug with a brazing tip on an Oxy torch...By heat it i mean really hot....Then let it cool on it's own....If this doesn't work... heat it again and use a fine directed spray of water on the plug...This will "shock" the plug and should loosen it.....Of course I assuming you can get the torch near the plug....

[Wayne Orwig]

I assume it is the insert that is turning a little.

At this point I would be doing what Rough Edge suggests. I would have that plug glowing red for a while. It may not be the right thing to do, but it would make me feel better.

[Antietam Classic Cycle]

   Been there...If the plug loosens a 1/4 turn and locks up it's likely the threads are galled.......Don't heat the head, head the metal base of the plug with a brazing tip on an Oxy torch...By heat it i mean really hot....Then let it cool on it's own....If this doesn't work... heat it again and use a fine directed spray of water on the plug...This will "shock" the plug and should loosen it.....Of course I assuming you can get the torch near the plug....

The plug is down in a "pocket", pretty much surrounded on three sides by the head casting.

[Chuck in Indiana]

The plug is down in a "pocket", pretty much surrounded on three sides by the head casting.

Oh. That makes it tougher. I'd probably just bite the bullet, pull the head, and machine it out. Fix the insert if it needs it, and try to ignore whatever else I found. You *will* find trouble on an old machine, of course.