Ulysses
Enthusiast
Is plug number 1 the closest to the front? If it is, it should be somewhat easy to shine a flashlight in and there and check out the threads. Might just be carbon build up and running a tap specifically designed to clean out spark plug holes shouldn't hurt the threads if care is taken while you clean it out, but you should be able to spot a cross thread if its at the bottom.
yeah, I'ld be a bit nervous too about running a tap through even if the head wasn't aluminum.
I actually had to tap out a new hole and put in a Helicoil spark plug seat in on another car. The cross thread was so bad that it couldn't be saved with a mere tap. I was too lazy to pull the head so I did it with the head on the block. I used a lot of grease on the tap and rigged a shop vac with tubes that came down to a size that would fit into the spark plug hole to **** up any particles that may have dropped down into the cylinder. Definitely was a lame way to do it but I was a young pup back then and didn't know better.
yeah, I'ld be a bit nervous too about running a tap through even if the head wasn't aluminum.
I actually had to tap out a new hole and put in a Helicoil spark plug seat in on another car. The cross thread was so bad that it couldn't be saved with a mere tap. I was too lazy to pull the head so I did it with the head on the block. I used a lot of grease on the tap and rigged a shop vac with tubes that came down to a size that would fit into the spark plug hole to **** up any particles that may have dropped down into the cylinder. Definitely was a lame way to do it but I was a young pup back then and didn't know better.