Stuck spark plug
 

Ran into an unusual problem. I started working on my 62 GMC with a 305. The PO had pulled 5 of the plugs and stuffed paper in the holes. I stuck some used plugs in there the other day as plugs so I could wash the engine. Yesterday, since the weather was not bad, I decided to run the valves and do compression check. Removed the driver side valve cover, only to find a push rod not engaging the rocker, it was just loose in there. I installed it back into position, figuring I would see what was up when I adjusted the lash.
I then started removing the plugs to spin the engine. Did the left bank OK, started on the right bank until I got to number 4, the plug the PO had never removed. I could see why. It was tight. I could break it loose just barely, to say it was tight coming out is an understatement. I took all my strength to even loosen the plug out of the cylinder, I must have managed a few complete turns until my long ratchet handle started jumping teeth. I then went to a 1/2 ratchet and it too was jumping teeth. At least it sounded like it was.
Right now I have Kroil in the plug valley hoping it will soak into the threads.
I am not sure if it is cross threaded or just rusty.
Today it rained and was lousy outside, maybe tomorrow, I may have to dig out the impact wrench to spin it out. Hope I don't have to pull the head on this one.

Re: Stuck spark plug
 

I'm always scared of this when I mess with the plugs because they have a little angle on them, but not alot. It sounds like you might need one of those grabbing remover tools kinda like this http://www.amazon.com/Irwin-Industri...t+remover+tool

Make sure you get the right size. You never know, you might find an old lawnmower plug was run in there just to plug the hole. :ahhhh:

Re: Stuck spark plug
 

Hopefully the penetrating oil will help. Sounds like a good time to chase all of the threads with tap. I hope it all goes well. Can you use slip a length of pipr over the ratchet to get some better leverage?

Re: Stuck spark plug
 

I do have a thread chaser for plugs. Problem is that as I try to loosen the plug more I hear what sounds like a ratchet slip, like I am putting so much pressure on the tool and it is giving, never had that problem before with Craftsman's tools. Next step will be a breaker bar, which can't slip. When you rock the socket back and forth, it feels like it is a 14mm plug under there, not much slop. All the rest of the holes spun in with no problems.

I am really starting to think that it was cross threaded when inserted and some yahoo seated it with an air tool. :noway:

I was looking and I see that Helicoil makes an nice thread repair kit. We shall see what's up soon. Still raining, supposed to clear up a bit tomorrow.

Re: Stuck spark plug
 

Sounds like an air tool will be required to get it out. Let us know how it goes.

Re: Stuck spark plug
 

That too would suggest as well as some heat. Use small propane or map gas torch.

Re: Stuck spark plug
 

jagarra,

If what just went by in Davis, CA is headed your way, I would have doubts about dry weather tomorrow.

Many years ago, I started working on cars with a Craftsman 1/2 inch socket set, and can't imagine getting the ratchet to jump teeth. The 3/8 inch Craftsman set is much easier to use and has fewer clearance problems, but doesn't seem nearly as strong. I would be careful about using a 3/8 inch drive impact wrench on this without breaking something.

The 305E (if that is what you have) engine plugs have a tall set of threads, but I have never in over 30 years had a problem getting them out. So your thought about cross threading sounds right if it is the correct plug for the engine. I think this means that you will be cutting new threads into either the plug or the head while it comes out, while messing up the other threads, which will probably make things more difficult as the plug comes out. Have you tried going at it a little at a time by alternating between screwing the plug in and out, while getting it a little farther out with each try?

Once the old plug is out, if you need to touch up the threads in the head, be sure to get the tap started right so that the new plug can seat correctly. And the worst outcome would be to break off a super hard tap in the hole.

Good luck. My experience with these old vehicles is that you will succeed in fixing this problem so that you can move on to the next.

JRMunn

Re: Stuck spark plug
 

The V6 used two different length plugs, if your heads required the short length thread and some one installed the long plugs 3/4" thread length and it did not interfere with the piston, the threads could be filled with carbon, which will make the plug very hard to remove. If the threads get stripped out of the head you can install a heli-coil in that cylinder with out causing any damage.

Re: Stuck spark plug
 

Yes I have been screwing it in and working it out a bit. there were some old plugs laying in the engine compartment, they looking like they were the long style. I used a old set from a Jag engine, they were the same length and the threads were at least clean. The number on the plugs laying in the engine compartment were R43XLS.

Re: Stuck spark plug
 

The R43XLS is basically a replacement plug for the superseded C43N Plug used in 396 V8 engines in the mid 60's, the 62 305D called for a C44S plug(long discontinued). Provided the R43XLS plug has the same reach as the C44S plug it will work though C44S plug is a step hotter. The early 305 V6's had shorter reach plugs so it's critical to use the proper length of spark plug.

Re: Stuck spark plug
 

Thanks for the information. I did some cross referencing on line and found an NGK substitute (I like NGK plugs) looks like a BP5S is the one, and they are a short reach plug.

Right now I am using plugs as a hole blocker to keep crud out. Looking forward to see what comes out of #4 hole. I will make sure not to crank it over with long reach plugs in there, thanks for the heads up.

gg

Re: Stuck spark plug
 

I have always used NGK when they crossed over, I have a set in my 1966 P/U V6 351.
Most of the time an NGK covers about 1 1/2 heat range of a normal plug.

Re: Stuck spark plug
 

The long reach plugs are 3/4 of an inch, isn't that right for the NGK BP5S ?

Re: Stuck spark plug
 

It would never occur to me to use an air wrench on a stubborn spark plug, a blunt force instrument in a delicate location.
Any but the most gentle of re-threading should be done with the head off, a move to avoid.
I have never heard of ratchet jump on anything but the cheapest tool.
A 1/2" drive 6 point socket of the RiGHT size and a a lot of patience, including rocking on and off, is your best bet.
A hard place to get effective heat to, but almost always a help.

Re: Stuck spark plug
 

Well guys, some good news. Got the plug out with a 3/8 spark plug ratchet. That noise I heard was the plug threads making the noise, kroil really helped and it came out perfectly. Ran a thread chaser down the hole, no damage to the threads or to the threads on the plug. It sure was carboned up badly, gap was non existent. pulled the rest of the plugs and removed the valve cover on the right side, 2 push rods flopping around on that side, no 4 was one of them. So a total of 3 pushrods flopping around, no wonder the engine didn't start. The last plug was also a #43, so all the plugs in the engine were incorrect length. None of the electrodes were flatten, so I guess there was no piston contact.
Going to set the valves close to specs and do a compression test today.

Re: Stuck spark plug
 

Normally a 62 305D will have 3/8 reach plugs, someone most likely didn't know and used the more common 3/4 inch reach plugs used on later 305E engines.

Re: Stuck spark plug
 

If a short reach plug is correct for your engine (which should be right for a 1962 truck) while the plugs you found in the engine compartment are long reach, it sounds like your problem could be a long reach plug in a short reach hole, with carbon burned onto the exposed threads. This is probably better news than cross threading (unless the longer plug has damaged the piston, and/or the piston has damaged the end of the plug - other members probably know if this is possible) and gives more hope to the idea of working the plug back and forth to gradually wear off the carbon without damaging all the threads in the head. And it also gives hope to using penetrating oil that should be able to run down the threads of an even slightly loosened plug to soften the carbon. But if you only have 3/8 inch of threads in the head, a 3/4 inch plug will need to be half way (another 3/8 inch) out before the carbon is gone. Again, good luck. This will probably not be the only time that patience may pay off in not creating a bigger problem while working on the engine or the truck. I have also learned that many replacement parts are hard to find, so it is better not to create a need for them.

JRMunn

Re: Stuck spark plug
 

Jagarra,

I see my previous message was received after you solved the problem. Congratulations on getting the plug out without any damage and, again, good luck with the engine and truck.

JRMunn

Re: Stuck spark plug
 

Big trouble in River City guys. I can only turn the engine over about 360 degrees. It stops hard at the same point from both directions. Timing gear screwed up?, I will start there and then take the heads off, has to be a reason why the pushrods bailed. It is stopping really hard, turning it over with a wrench on the crank bolt. :ahhhh:

Re: Stuck spark plug
 

Still working on getting the front of the engine torn down. Pulled the rocker assemblies from both sides wondering if they were involved in the lock up, nope. Number 4 pushrod was bent, so I straightened it out. Down to the point of pulling the front damper off, hope I can get an impact in there, if not the radiator will have to be removed to get a clear shot of the bolt.

One thing I found curious as I moved the crank in it's travel, I saw very little rocker activity going on.

I have one of those bore scopes, with a camera on the end, which lights up, I am going to poke it into the chambers through the sparkplug holes, see if there is anything interesting in there, I am for sure starting with #4.

Considering the amount of carbon on that plug when I got it out, it had been not opening the exhaust for a bit. From what I have seen the engine is very clean, no sludge on the rocker areas of the heads. Maybe the low miles is correct. Makes you wonder what broke.

Re: Stuck spark plug
 

I've seen a 305 turn and then lock up, the problem was an excessive build up of carbon on one piston. This may be the problem with your engine but then again it's just a possibility and the problem might be something else.

Re: Stuck spark plug
 

That is a very good point. I was trying to see the top of the piston with that bore scope. Results were inconclusive. I have the damper off, couple of bolts to go and the timing case will be off. If that is OK, the head on the passenger comes off.

thanks,

gg

Re: Stuck spark plug
 

My *guess* would be that the timing chain may have broken. You might be able to tell by using your scope down the opening the fuel pump uses (ie. take the pump off...)
Although judging from your postings you will probably already have the cover off before you read this.

If you haven't noticed, there are bolts from the oil pan into the cover, don't forget to look for those and remove so you don't bend the pan.

-<at least I think there are bolts there. Been too long since I tore one apart and have taken apart way too many different engines to keep them straight anymore it seems. I recall 4 bolts, and loosening the pan so that the timing cover comes off easier.>-

Re: Stuck spark plug
 

Yes, I figured there were bolts there. Got the cover off and everything looks great, little marking on the gears, the chain is a bit loose, but that may be normal as it drives in one direction.
Started taking the intake manifold off, there are only 8 bolts holding it in correct. That baby won't move at all. I have a bar between the heads and I have another longer bar across that with the edge under the manifold and it isn't going anywhere especially up.

Finally got enough leverage and a lead hammer, it popped off.

Re: Stuck spark plug
 

The manual shows about 14 bolts.
I would have checked my spare heads rather than a manual but ... well we kind of buried them (on shelves but about a half hour of moving stuff to get to them)

If you have it off then...

Since you have indicated you have the timing cover off... and the engine only rotated so fat (same spot every time) I wonder if you will find a rod cap came off and the piston rod is hanging loose. Until you rotate the crank up against it.

Re: Stuck spark plug
 

Worst case scenario is something dropped into the cylinder. The dead stop on rotation in each direction can also be the carbon coating sheared from the top of the piston. Doesn't take much to stop the piston. Not uncommon to see on an engine that has been dropped hard. Tape a piece of narrow hose to a vac and suck it out. Ive done it a couple times. Maybe you will get lucky. Good luck.

Re: Stuck spark plug
 

IT'S FREE, FREE!!!
Yesterday I went to my local radiator guy to drop off the radiator from the truck. I was telling him about my tail of woe and how the engine was not turning over completely. He suggested I put some the Marvel Mystery Oil in the cylinders and leave it over the weekend. Sort of work it back and forth.
I had some of that stuff as I was adding it to the gas of my Miata. So I stuck about an oz in each cylinder, a double dash on #4.
Later this morning I was playing with it seeing if it would turn over, stopped a couple of times, then all of a sudden I was turning it round and round.
Went a got some more MMO and added a bit more the cylinders, figured I would let it sit for awhile. I have been cranking it over by hand, seems to move a lot easier than it did before.
Monday I plan on laying paper towels over the plug holes and using an impact to crank it over, want to see the color of what comes out.


YAHOO!!

Re: Stuck spark plug
 

Great news! MMO is a great product. A little added to your gas tank is good for an engine.