Stuck spark plug

[jagarra]

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

[Clyde]

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.

[bigblockv6]

Originally Posted by jagarra

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

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

[Jim A]

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.

[jagarra]

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.

[bigblockv6]

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.

[jrmunn]

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

[jrmunn]

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

[jagarra]

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.

[jagarra]

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.