What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Need help on spark plug thread problem

rvanstory

rvanstory

Well Known Member
Was cleaning spark plugs today for regular maintenance during an oil change. As I do periodically, was using a thread chaser to clean up the threads for easy spark plug installation / removal. On my #1 cylinder, I screwed the chaser in too far and it went past the threads. Now, as I try to back it out, it is trying to cross thread. UGH!!!

I fought it for over an hour, but it simply will not come back out easily. So, tomorrow my plan is to "force" is out. My hope is that it will come out, but anticipating my threads to be toast.

How hard is it to replace the heli coil on a Lycoming IO-540? What tools are needed? Is this something I should hire an A&P to do for me? Any advice would be appreciated.
 
rvanstory said:
Was cleaning spark plugs today for regular maintenance during an oil change. As I do periodically, was using a thread chaser to clean up the threads for easy spark plug installation / removal. On my #1 cylinder, I screwed the chaser in too far and it went past the threads. Now, as I try to back it out, it is trying to cross thread. UGH!!!

I fought it for over an hour, but it simply will not come back out easily. So, tomorrow my plan is to "force" is out. My hope is that it will come out, but anticipating my threads to be toast.

How hard is it to replace the heli coil on a Lycoming IO-540? What tools are needed? Is this something I should hire an A&P to do for me? Any advice would be appreciated.
Click to expand...
I can't see how it is getting cross threaded if it was threaded in correctly. Lets hope your heli coil does not come out with it but if you have to replace it, it will require a special tool which you can rent. Putting the heli coil is not hard and there is a special coil with is .002 larger which you will need to use.

Good luck.
 
Wow... so the last thread of the chaser went through...or several threads just past. Regardless, Randy I'd get an A&P and learn from them. Cheap insurance on an expensive engine. No help, I know, but my .001 cents worth. Dang it !
 
Pull the cylinder, screw the chaser all the way thru and pull it out from the piston side. Test helicoil threads with a new plug, look for damage. If okay, put cylinder back on. If not okay take cylinder to a shop, they’ll R&R the helicoil
 
You must log in or register to reply here.
Back
Top