1971 spark plug problem.

[BigAl]

Recently purchased 1971 4 door. While doing a tuneup I removed the plugs from the passenger side without a problem. On the driver side all 4 of the plugs were unbelievably difficult to remove.
I actually thought that I might break one or more of them, but they came out. The problem is that I can't install new plugs. They would not grab the threads. I tried using a spark plug thread chaser but I can't even start that in the plug holes. It's like the holes are too small. The plugs that were installed were the stock 18mm size. Totally confused and not sure what to do next. Trying to avoid having to pull the head.
Any thoughts?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[warnest]

Sounds like the prior owner may have installed the plugs in a hot engine. I made this mistake with my first '68 Thunderbird when I was too young to know better back in 1972. Same problem as you describe.

Here are some ideas:

• For starters make sure you are working with an ice cold engine.
• Take a close look at the threads in the heads. You might need a mirror to take a phone picture.
• Look closely at the threads on both the old plugs and the new ones for differences.
• See if your thread chaser works on the passenger side. Was there a problem with installing the new plugs on the passenger side?