spark plug thread chaser

[Donald]

So the old Ford 300 engine in my snow cat. I started all the plugs in the spark plug holes and left the engine alone for 3-4 years. This weekend I unscrewed the spark plugs and the holes are rusty, new plugs do not want to go in easily.

i ordered a spark plug thread chaser.

How to I make sure that I get the tool in at the proper angle so I do not make the rusty hole worse?

 

[andyd]

Do you have a plumber's brush for cleaning copper pipe insides? Clean the threads, oil them, and start the plugs in by hand,

 

[supton]

I'd think a chaser would be unable to cut new threads. I'd want to put some grease on, so nothing falls into the engine, which should also lube the threads. So I'm thinking it's just a matter of feel--if it feels cross threaded, it is. If not, then just turn a bit harder.

 

[JohnG]

A proper thread chaser should have a generous taper at the nose to prevent just what you are saying. Just be careful and gentle. I'd say that if you use oil, that should keep most of the debris from falling into the cylinder.

 

[Convert]

I use one on my Moto Guzzi Motorcycle a couple of times a year, if you have ever used a tap you wont have any problems.

I bought a NOS cylinder head and was installing a spark plug and it would only go in 1/2 way due to corrosion on the thread's,
ran a chaser through the hole and everything was good. Head was off the bike but was going to be installed so it was easier to do the chasing .

You can do it!

Convert
Tom

 

[CT8]

Don't forget to put grease in the flutes of the thread chaser to catch the chips of metal / rust carbon etc.

 

[JeffKeryk]

I spray a little WD-40 down the plug hole to clean and lube the threads.
And just a slight brush of anti-seize on the plug threads.

If I can't spin 'em in by hand, I find out why before continuing.
Finish with torque wrench.

Perhaps try this; if it fails go for the greased up plug chaser.
Easy peasey. Good luck.