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Discussion Starter · #1 ·
Hey All,

What would cause a plug to not fire at idle RPM but begin sporadic firing once you reach 1,500-2,000 RPMs? I would think a fouled plug would fire or not fire irregardless of RPM level....or am I missing something?
 

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I had one on my old LUV truck decades ago, plug was new, looked good when I pulled it, but, in the engine, no fire to number 4. Drove me nuts for a day or so, went over everything. Then, I took the plug and held it up wire end up. What a news flash. The inner porcelain inside the plug wasn't connected to the rest of the insulator, and when the plug was held in its operating position, the tapered insulator moved down the center electrode, closing off the plug gap. New plug (again), fixed it. Who'd A Known???
 

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Discussion Starter · #6 ·
Thanks for the replies....I was planning on replacing the plug when I have a little time....just thought it odd and that I'd get some opinions on why.... Had a rich carb issue recently so I half way expect a fouled plug....but don't know why the increased RPMs would overcome a fouled plug....
 

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Had a set of brand new AC Delco plugs that made the 406 run like crap down the 1/4 this year. After several passes and thinking it might be something else I replaced the plug with the 2 year old ones. Car ran like a million bucks to 7400 RPM after that. Just had a guys snow blower do the same thing, he bought a new carburetor based on the shops diag. I swapped the spark plug on the engine and it ran like new, loved the surprised look on his face.
 

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Discussion Starter · #8 ·
Had a set of brand new AC Delco plugs that made the 406 run like crap down the 1/4 this year. After several passes and thinking it might be something else I replaced the plug with the 2 year old ones. Car ran like a million bucks to 7400 RPM after that. Just had a guys snow blower do the same thing, he bought a new carburetor based on the shops diag. I swapped the spark plug on the engine and it ran like new, loved the surprised look on his face.
Interesting.....Not surprising given the quality of parts these days..... All that outsourcing to get cheap parts/goods got us exactly that....cheap junk.

Today I went to pull the offending plug..... The guy who installed the crate engine had used a 'shortie' plug due to clearance with the header tube. The head of this plug is so 'short' that I can't get a socket on it as the head itself has a recessed opening sort of like a bowl type indention that prevents the socket from going on....You can't get an 'end' wrench on it either. I have no idea how he installed this piece of junk.....and he recently retired so I can't ask..... I can't figure a way to get this plug out!!!!! Ideas?
 

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Can you modify the socket?
I can't picture in my mind what you are describing.
I have cut the end of a socket off so I have 1/2" of socket the end without the square hole.

Then weld that to a steel rod or all thread rod and make my own wrench for tight or odd spaces.

I have notched sockets to fit certain things also.
 

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Discussion Starter · #10 · (Edited)
Can you modify the socket?
I can't picture in my mind what you are describing.
I have cut the end of a socket off so I have 1/2" of socket the end without the square hole.

Then weld that to a steel rod or all thread rod and make my own wrench for tight or odd spaces.

I have notched sockets to fit certain things also.
The thickness of the socket doesn't allow it to go into the concave recess around the plug.....the socket hits the head surface (inside that concave area) before the socket can go far enough down onto the plug to fit securely....Not sure how you'd make a socket less thick in its wall....

The plug has such short 'shoulders' on the 'nut for a lack of a better word' that you place the socket on that it literally goes into the concave area on the head and only a tiny portion of the 'nut' sticks out....maybe 1/16" or less for you to try to put the socket on....So it wasn't deep enough in the socket to catch and unscrew.... Hope that makes sense....
 

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Yep I get the picture now.
I have had to thin many wrenches and sockets.
Bench grinder or angle grinder or da sander will make it thinner.. sand the outside down.

Now on a socket if you look at the end that goes onto the nut many will have a taper.
Sand or grind that taper all the way gone.
You must put the socked in even farther if it has a taper and more likely to strip the nut you are removing.

Yea I know not a nut but a socket.
But remember that taper when you have a stripped nut.
I hate taper on wrenches and sockets.

They do that to make it easier to get it on the nut or bolt.
Easier ... Ok if that was hard to get on without a taper you need to quit using tools.
That's my take on that.

Sand that socket thinner and you will get it out.
 

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Discussion Starter · #12 ·
Yep I get the picture now.
I have had to thin many wrenches and sockets.
Bench grinder or angle grinder or da sander will make it thinner.. sand the outside down.

Now on a socket if you look at the end that goes onto the nut many will have a taper.
Sand or grind that taper all the way gone.
You must put the socked in even farther if it has a taper and more likely to strip the nut you are removing.

Yea I know not a nut but a socket.
But remember that taper when you have a stripped nut.
I hate taper on wrenches and sockets.

They do that to make it easier to get it on the nut or bolt.
Easier ... Ok if that was hard to get on without a taper you need to quit using tools.
That's my take on that.

Sand that socket thinner and you will get it out.
Thanks for the idea...I'll take a look at that....
 

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Yep I get the picture now.
I have had to thin many wrenches and sockets.
Bench grinder or angle grinder or da sander will make it thinner.. sand the outside down.

Now on a socket if you look at the end that goes onto the nut many will have a taper.
Sand or grind that taper all the way gone.
You must put the socked in even farther if it has a taper and more likely to strip the nut you are removing.

Yea I know not a nut but a socket.
But remember that taper when you have a stripped nut.
I hate taper on wrenches and sockets.

They do that to make it easier to get it on the nut or bolt.
Easier ... Ok if that was hard to get on without a taper you need to quit using tools.
That's my take on that.

Sand that socket thinner and you will get it out.
I was gonna say the guy probably didn’t use a spark plug socket but instead used a thin wall regular deep socket, possibly shaved flat, to install that plug.

Or, based on what the OP said about the previous person working on the car - maybe a small hammer. :p
 

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That's what you need to use.A regular deep wall socket will work in this case they are made thinner than a spark plug socket.
 

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Discussion Starter · #15 ·
Yep I get the picture now.
I have had to thin many wrenches and sockets.
Bench grinder or angle grinder or da sander will make it thinner.. sand the outside down.

Now on a socket if you look at the end that goes onto the nut many will have a taper.
Sand or grind that taper all the way gone.
You must put the socked in even farther if it has a taper and more likely to strip the nut you are removing.

Yea I know not a nut but a socket.
But remember that taper when you have a stripped nut.
I hate taper on wrenches and sockets.

They do that to make it easier to get it on the nut or bolt.
Easier ... Ok if that was hard to get on without a taper you need to quit using tools.
That's my take on that.

Sand that socket thinner and you will get it out.
Jeff...thanks for the tip. Nothing like 'shade tree' know how to get the job done! It worked perfectly. I used a bench grinder with a stone...held the socket up to the side of the stone so that I could get the entire socket onto the stone surface and get an even/level grind.

All the years I've been tinkering and fixing I never gave any thought to the beveled edge at the end of a socket..... I love learning new tricks like this....It makes you feel kinship with Macgyver when you can make things work like that....

Thanks a bunch for taking the time to help out.....It saved me a shop visit.
 

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@Santacarl next time you see a stripped nut or bolt look closely and you will see most of them are not
all the way stripped.
There is usually an 1/8 to 1/4" of the nut that is not stripped out and if you remove the taper from the socket
You can get onto that good portion and remove it sometimes.

And look at the sockets that you have been using for years.
Are they sharp in the corners or a little rounded and stripped out.
Grind them down until you get good edges back.

You probably thought that far into it by now.

Glad it worked out for you.

Oh and you can apply Lapping compound to a Philips screwdriver to make it bite better into an almost stripped slot.
No lapping compound?
I wet the end of the screwdriver and stuck it into some dirt a couple times when working away from home on other peoples stuff.

Happy Holidays.
 

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Discussion Starter · #17 ·
@Santacarl next time you see a stripped nut or bolt look closely and you will see most of them are not
all the way stripped.
There is usually an 1/8 to 1/4" of the nut that is not stripped out and if you remove the taper from the socket
You can get onto that good portion and remove it sometimes.

And look at the sockets that you have been using for years.
Are they sharp in the corners or a little rounded and stripped out.
Grind them down until you get good edges back.

You probably thought that far into it by now.

Glad it worked out for you.

Oh and you can apply Lapping compound to a Philips screwdriver to make it bite better into an almost stripped slot.
No lapping compound?
I wet the end of the screwdriver and stuck it into some dirt a couple times when working away from home on other peoples stuff.

Happy Holidays.
Ah Haaaaah...more cool tricks...Thanks Jeff.
 

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All good tips and tricks but when the outside of a bolt or a nut is messed up then technically it is not a stripped bolt or nut.That would be called a rounded off fastener.
A stripped bolt or nut would have threads that are ruined while a rounded off nut or bolt would have the sides or flanks that are ruined.
Saying it the wrong way could have someone looking to help you out with the wrong tools or suggesting the wrong approach for your particular problem.Also sometimes a stripped fastener leads to a rounded off nut or bolt because the threads being messed up makes it harder to remove that bolt out of its place.
 
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