Hey guys, i need some help, i cross threaded my cyclinder 2 plug. Now do i need to remove my heads to tap them?? or can i do it on the car?? I know i will have to remove my Longtubes, as the cyclinder 2 primary is in the way, but what about the shavings?? can i like suck them out some way or is it a must to remove the head?? Also, what is involved in removing the head??? I have a LT1, so would i need to remove the intake? Or just the valve cover etc. Thanks for the help

Dave

 

I'd just pull the head and do it on a bench top, less worry of dropping fillings and shavings into the cylinder and risk damaging the cylinder walls.

Cylinder head removal is fully detailed on http://ls1howto.com

 

How bad is it? Just a couple threads? If you're really stuck, I'd put some heavy grease (axle grease?) on the tap, and run it through slowly (put it in 1/4", remove it, clean it off, put it back in, etc, make sure she's comfortable errr nevermind). The heavy grease will hold the shavings so you SHOULD be okay.

I still recommend pulling the head, btw.

Dope

 

Thanks for the replys guys, hopefully its not a long process, thanks again.

Dave

 

Any of you guys know the correct tap size that should be used?

 

The spark plug thread is 14 mm X 1.25. If the thread is not too damaged (just the top thread or two) you can repair it with the tap. Otherwise you will have to install a thread insert.

Best way is to remove the head from the car. Thread the tap using oil or (WD40) with your fingers into the plug hole from the combustion chamber side out. That way it will start straight in the existing threads. Turn it with a wrench or tap handle when you get to the damaged area. It will be nearly impossible to pick up the threads (not to mention start the tap straight) from the spark plug side of the head whether the head is on or off the car.

Steve Demirjian
Race Engine Development

 

Good info, thanks

Dave

 

this happened to me one time.

i got a spark plug hole chaser from autozone, put a ton of grease on it to both lube it and catch the threads, ran is through the crossthreaded plug hole. than fired the motor for a few seconds without that plug there to blow out all the crap


worked great

 

(put it in 1/4", remove it, clean it off, put it back in, etc, make sure she's comfortable errr nevermind)

buahahahaha.

 

That idea sounds like a winner to me.