73 Blazer 350 spark plug stuck

[Grit dog]

Just curious, how long were the plugs in there for it to look like that?

Since 1973, or maybe 2020 in the rust belt! Lol

 

[77Dmax]

I like to use the square easy outs. It's nice to wiggle them.

 

[Jimmy the Blazer]

Had to get in a with vinegar and a pick to clean out all the rust around the casing. I hit it with heat on a propane torch and hit it with deep creep but still not budging. Got it soaking overnight in deep creep and will see if hitting it with heat again may let it bust loose.

 

[Jimmy the Blazer]

Personally I'd give up on the easy out,and this will buy you some time also,while the deep creep soaks in. Buy a tap for the plug hole,also buy a left hand drill bit,in correct tap size. I'll get you the size. Drill the plug with the left hand bit sometimes,not always but sometimes the bit will bite and spin the remaining threads out. If you don't get that lucky now you are at tap size and can retap the holes. Grease your bit and your tap to collect the chips. FYI left hand bits are a real thing,not a joke I made up, they turn counter clockwise,instead of clockwise,and when you get your broke fastener drilled that thin sometimes they'll spin the remaining fastener back out. 15/32 bit.

I have a tap and tool dye kit. I don't want to drill and get any filings falling inside using a left hand bit.

 

[Ricko1966]

I've drilled and tapped oil galleys on assembled engines. Installed IDK how many plug inserts.Grease your bit,grease your tap and go slow. And the tap I listed is a back tap,it goes in the hole expands and cuts threads on the way out.

 

[Jimmy the Blazer]

I like to use the square easy outs. It's nice to wiggle them.

Do they leave room to pick them out if they snap in the cavity. I had a round one break in one of the exhaust manifold bolts that were rounded and left to rust for years. It wouldn't drill into and I dremeled the bolt head off instead. I don't want to run into that with a spark plug socket and not be able to get it removed if it breaks.

 

[PrairieDrifter]

You need a real torch like I said. A bottle torch won't cut it.

 

[Grit dog]

I have a tap and tool dye kit. I don't want to drill and get any filings falling inside using a left hand bit.

Agree, it’s kind of a connundrum. I’ve necked down a shop vac to a small hose before. You could fish around with that after drilling. If you have to drill and tap. And it may be a good excuse to buy a bore scope. Some are pretty reasonably priced now.

You need a real torch like I said. A bottle torch won't cut it.

Agree for the most part. Although Mapp gas does burn hot enough in most instances in my experience. Takes much longer especially on a huge heat sink like an engine head though. I don’t own a cutting torch and have removed a lot of rusted fasteners with mapp gas heat.
But my next dedicated effort at this point would be to get a good stubby easy out with the fine splines. Not the hardware store corkscrew type. Get it seated good in there and pour the heat to the head (not the easy out/spark plug) and see if it works. Next step, LH drill and possibly chase/tap.

 

[Ricko1966]

If I was really worried about chips in the cylinder, I'd put a trash bag over the top of the carbureator and put the air cleaner back on to seal it. Move the hoses on the shop vac so it blows instead of sucks ,stick the hose in the tailpipe and turn the engine until air is blowing out the plug hole. Now stuff a rag around the hose,and wrap it in duct tape. Do your business then blow compressed air through the plug hole and through the exhaust heck hang a small pickup magnet in the hole while you are blowing compressed air in the tail pipe. If you're really paranoid pull that valve cover Make sure exhaust valve is wide open and intake valve is completly closed. Go drill a hole in something on the bench. Watch, at the right speed the shavings come off in curls,up the drill flutes.

 

[PrairieDrifter]

Agree for the most part. Although Mapp gas does burn hot enough in most instances in my experience. Takes much longer especially on a huge heat sink like an engine head though. I don’t own a cutting torch and have removed a lot of rusted fasteners with mapp gas heat.
But my next dedicated effort at this point would be to get a good stubby easy out with the fine splines. Not the hardware store corkscrew type. Get it seated good in there and pour the heat to the head (not the easy out/spark plug) and see if it works. Next step, LH drill and possibly chase/tap.

Agreed. Mapp will do most things for the average shade tree. But being we are working on the head/engine, it will not cut it or you'll be there for an hour lol.

People know about heat sinks, but they don't understand HOW much heat transfers on stuff like this.

 

[Jimmy the Blazer]

I've drilled and tapped oil galleys on assembled engines. Installed IDK how many plug inserts.Grease your bit,grease your tap and go slow. And the tap I listed is a back tap,it goes in the hole expands and cuts threads on the way out.

No one in my town has left handed drill bits. I'm not sure what size left hand drill bits I need so I can order online.

 

[Ricko1966]

Post 14 has all the info you need.

 

[Tonimus]

To Rick you listen. I busted off an oil fitting inside of my Hughes built TH350, like two weekends before a big race. Couldn't get it out with anything. A greased left handed bit, go slow, remove the chips from the drill periodically and re-grease. Still running that trans. And an engine cylinder is way less sensitive to debris than a transmission.

 

[Jimmy the Blazer]

Got no spot in town to get my oxygen and acetylene bottles filled,have to order left hand drill bits big enough for this,so in the meantime of waiting,I tried what we did years back with as much heat as I could throw at it with a propane torch and $1.49 of birthday candles I threw at it,the wax got enough into the threads to break free easy with my cheap exractor with a cresent wrench. I had to clean an inch of rust out of the channels and tried propane for days with pb blaster and deep creep then vinegar to get it enough space to let that wax down in there. I had to be patient using a pick to scrape out that thick rust but in the end wax won the day to break it free.

 

[PrairieDrifter]

Got no spot in town to get my oxygen and acetylene bottles filled,have to order left hand drill bits big enough for this,so in the meantime of waiting,I tried what we did years back with as much heat as I could throw at it with a propane torch and $1.49 of birthday candles I threw at it,the wax got enough into the threads to break free easy with my cheap exractor with a cresent wrench. I had to clean an inch of rust out of the channels and tried propane for days with pb blaster and deep creep then vinegar to get it enough space to let that wax down in there. I had to be patient using a pick to scrape out that thick rust but in the end wax won the day to break it free.

Hell yeah!

Proper heat and lube. 95% of the time it works. The 5% it doesn't is usually because it was over torqued before it rusted in place, or there was never a chance at all.