Spark Plug Thread
Thread Starter
Intermediate
Joined: Jun 2017
Posts: 32
Likes: 3
Spark Plug Thread
I am replacing spark plugs on my 73 454 they take a T44. I am having a problem with one of the holes and would like to clean up the threads. Everything I see says this is a 14mmx1.25. But in 1973 this would be an SAE designation. Is the 14mmx1.25 the identical thread?
Racer
Joined: Apr 2016
Posts: 493
Likes: 65
In the past, when I had to clean up any threads, and didn't know what size they were, I'd use whatever came out of the hole (as long as it's the correct threads for the hole) and use that.
This will cost you a spark, or maybe just use an old one. I cut a "V" kind of shape in the threads. But, I cut the one side of the V vertical with the threads, similar to the picture, but I make mine perpendicular to the threads, and not angled. Either is personal preference. Use a good bit of wheel bearing grease to hold any thread particles that may come out of the hole
Good luck
This will cost you a spark, or maybe just use an old one. I cut a "V" kind of shape in the threads. But, I cut the one side of the V vertical with the threads, similar to the picture, but I make mine perpendicular to the threads, and not angled. Either is personal preference. Use a good bit of wheel bearing grease to hold any thread particles that may come out of the hole
Good luck
Melting Slicks
Joined: Mar 2008
Posts: 2,989
Likes: 198
From: Meriden CT
In the past, when I had to clean up any threads, and didn't know what size they were, I'd use whatever came out of the hole (as long as it's the correct threads for the hole) and use that.
This will cost you a spark, or maybe just use an old one. I cut a "V" kind of shape in the threads. But, I cut the one side of the V vertical with the threads, similar to the picture, but I make mine perpendicular to the threads, and not angled. Either is personal preference. Use a good bit of wheel bearing grease to hold any thread particles that may come out of the hole
Good luck
This will cost you a spark, or maybe just use an old one. I cut a "V" kind of shape in the threads. But, I cut the one side of the V vertical with the threads, similar to the picture, but I make mine perpendicular to the threads, and not angled. Either is personal preference. Use a good bit of wheel bearing grease to hold any thread particles that may come out of the hole
Good luck
Safety Car
Joined: Sep 2013
Posts: 4,355
Likes: 2,631
From: Draper Utah
For chasing spark plug threads buy this tool called a Powerbuilt Back Tap. I bought mine for about $15 on eBay or Amazon. You insert the tool into the hole, twist the **** to expand the thread chasers and then screw the tool out. It works like a charm and any crap or shavings fall outside the cylinder.
Last edited by Iceaxe; Jul 12, 2017 at 11:33 AM.
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Racer
Joined: Apr 2016
Posts: 493
Likes: 65
That's why I said use a good bit of wheel bearing grease. And, I'd have the piston at the top of the stroke, I'd use a vacuum tube in the cylinder, and maybe even some compressed air. I thought we all knew how to do that, and didn't want to insult anybody's intelligence. I guess I should cover EVERY step extensively from now on?
Racer
Joined: Apr 2016
Posts: 493
Likes: 65
I would hope we all know that a thread chaser, or a tap of any kind, of the right size, is the best. But, if you don't have the money to buy it right now, or it's midnight, or you really want to get it done, this is a suggestion to do just that.
Melting Slicks
Joined: Sep 2016
Posts: 2,169
Likes: 941
From: Wauconda IL