Removing spark plugs

chevrolet
2500

#1

I have an '89 chev 3/4 ton plow truck with a 350 v8. I worked on repalcing battery cables to starter and rewiring the 4wd actuator on the front axle. Went to move it off the blocks and the rear spark plug on the right side came apart. What happened was the porcelin blew out of the metal. I let it sit for 2+ weeks and today worked on removing and replacing what was left with a new plug. Have you ever seen this or had to remove the remaining plug end? the corrosion on the head along the manifold was such that, even after trhing to clean with a long screw driver and hammer to remove the corrosion, I could still not get a socket on. I ended up driving a 3/8 inch ez out in the spark plug so that i could use a 3/8 inch extension on the EZ out. I then used a 12 inch cresent wrench with a cheater pipe to break it loose. After about 3 hours i finally got it to come out.
Started the truck and the 3rd one from the front on the drivers side blew out. After 2 hours of working on it similar to the other side, breaking (actually) exploding an extension, with snow coming down, and after running the truck to heat the engine, I gave up.
Any ideas this side of a torch on removing the plug metal?
by the way I also tried to remove other plugs before they come apart and could not get the socket to grab the metal due to all the corrosion metal around the plug. This is the worse plugs I have encounter thus far.


#2

Yes, but it involves towing and paying somebody else to fix it because it is likely to happen again and you may not have the spare time to change every plug. It’s getting to be 18 hours at three hours per plug after the time spent on the first two. You are going to have to use the truck for plowing sooner or later.

The other maybe that’s in my bag of tricks is to use the sockets that are designed to remove nuts and bolts that are rounded or rusted. Once the ceramic is gone they will probably remove the plug nicely.


#3

You have to get the rust, corrosion, and crud out of the spark plug holes. The big question I have to ask is: Just how long has it been since these plugs have been replaced?!? To have the porcelain break up that bad on two plugs tells me these plugs are ancient. The level of corrosion around the plugs backs it up. You’ll need some sort of mix of rust buster and flame action to get these clear enough to put a socket on them. Try hosing them down with P’Blaster, Blue Torch, or other such product to help break up the formed rust. Use compressed air to blast out as much crud as you can loosen up. Like @pleasedodgevan2 said, this is a time consuming task that will take either your time or money to pay someone else to do this for you.

Busting up the porcelain to get to the steel body is a bad idea. The steel core of the plug will be in the way unless you can remove all of it, but you risk dropping some very hard porcelain pieces into the cylinder if you bust out the core. Any porcelain into the cylinders may damage it once you start it back up. And they don’t need to be big pieces to do serious damage.


#4

the porcelain part of the plug came out from the compression on the engine whole, I have both pieces. I have tried to scrap, tap with screw driver and hammer at the rust with little or no effect. I thought of the torch as it will burn away the rust before it melts the plug. But as you know these are at lovely places to get a torch into and be able to just heat ‘around’ the plug. I did hit them with PB blaster then had to after 2 hours on that last one with no movement, just had to quit. Frustration level was beyond …
I guess with the weat as it is i may have to park it ‘again’ another year and use my old 2x4 '66 ford plow truck. I have to work on the carb on that but am hoping that one of the 4 extra carbs will just bolt on and work. That truck last year when I was plowing with it would only run with the choke 7/8 of the way out, replaced filter but made no difference. Not sure what is up with that, can there be dirt in the carb? can it get past the filter? It has that filter built in the fuel pump canister.


#5

I haven’t seen the porcelain insulator blow out of the metal grounding body of the plug, but I’ve heard of it happening. If the ceramic is damaged at any point in its life, probably due to thermal or physical shock, there’s not a whole lot else holding the center in. It’ll inevitably fail.

Since plowing is done in cold weather, and carbs can be prone to icing, that might be a possibility, especially of the vehicle is rarely used…which also raises the question of “how old is the gas”? Beyond that it’s back to basics; float bowl problems (a saturated or leaky float?), gummed up or partially plugged needle valve, etc.

Before bolting on an old carb I’d strongly suggest rebuilding it. Age problems such as deteriorated diaphragms and seals, saturated floats, gummed needle valves, and such might exist in the other old carbs you’ve had in storage as well as the one currently on the engine.


#6

It’s basically a glass to metal seal and once corrosion creeps between them the bond is broken and they separate. The bad news is that the ceramic center helps stop the metal ring from deforming when you apply torque to remove the plug. When the ceramic is gone, the ring many become even more difficult to remove.

Patience is key. As you have done, step back and cool off. Come back at it with renewed vigor and positive outlook later on.

Try a metric 6 pt to fit over corrosion. When it breaks up a bit, you may be able to tap the correct size SAE 6pt socket over the remains.


#7

How about trying a Gator Grip Wonder Socket. I would send you a link but I have no idea of how to do that. Just Google it.


#8

TT, I agree with your post, but I believe you have the chicken before the egg. Corrosion cannot happen in a glass to metal seal unless there’s an occlusion or inclusion in the seal or damage occurs. Glass having a substantially different coefficient of expansion thermal shock can also cause a failure, as can mechanical stress.

Anyway, stuff happens. I wonder if an easy-out would get a bite on the hole?


#9

I had about 2 foot of torque on that 3/8 inch easy out even after heating the engine, the plug metal will not move. I am hear where we are expected to get 30 inches of snow or thereabouts, at the least I moved it away from the garage door running on 7 cylinders. I might try to buy a socket that is a ‘deeper’ than the deep 6 point socket that I have that will reach the plug metal. I am wondering if that ez-out is expanding the plug metal to a point where it helps hold it in? Then when i try to turn it, the metal expands against the threads?
If i use the torch it will be to loosen some of the rust around the plugs that remain. Oh by the way I took out #4 plug with little difficulty. That plug was of a different make which made a world of difference.
when i get a chance and the snow quiets down, and the weather is above zero I plan to work on it again.


#10

TSM- “Corrosion cannot happen in a glass to metal seal unless there’s an occlusion or inclusion in the seal or damage occurs”

Perhaps the way I described it is not clear. It doesn’t start IN the seal, the corrosion starts at the exposed interface and works down along the interface until the seal is ultimately compromised. We do a number of various glass (ceramics, borosilicates etc) to metal seals using various metals (primarily SS or kovar). The metals need to be properly oxidized first to promote the seal and you probably already know all this stuff. We can tolerate a certain level of defects in the interface and still retain a hermetic seal for the life of the product. If the metal begins to corrode at the interface, it continues to progress down the metal to glass seal until it’s breached and then failure. That’s the creepage I was referring to.


#11

A good idea to verify – after removing each plug – that the threads in the block head haven’t been damaged. This is not an uncommon thing when plugs are difficult and stubborn to remove. If the threads are damaged, you are better off $$ - wise usually to first get the threads fixed, before trying to install new plugs.


#12

TT, I stand corrected. It’s been some years (perhaps 25) since I’ve worked with glass to metal seals, and I forgot about corrosion resulting from not treating the metal.