What size tap for spark plug CA77

texasgrape · Post by **texasgrape** » Wed Jun 29, 2016 8:40 pm

PO cross threaded one of the plugs. I need to chase the threads. What size tap do I need? Plugs are D8HA, 1967 CA77. Also what about the small amount of fine shavings going down the cylinder? Is that a concern? Vacuum them out?? Thanks.

texasgrape · Post by **texasgrape** » Thu Jun 30, 2016 2:13 pm

After talking w/NAPA and local mechanic, it's a 12mm x 1.25. I bought one at NAPA and it says: Spark Plug Tap on the package.

texasgrape · Post by **texasgrape** » Fri Jul 01, 2016 6:12 pm

Lastly, just a tip to keep shavings (if any) out of cylinder: I used assembly lube in the big grooves of the tap; it's sticky enough that the shavings stick to it. If you don't have assembly lube, a thin coating of grease. Use oil as you tap and don't go for it all at once. A few threads then back it on out and clean tap, repeat . . . worked for me.

james robert · Post by **james robert** » Sat Jul 02, 2016 9:58 am

Texasgrape, Somewhere around here I have a tread chaser that i bought from an auto parts supplier. It came with two different thread sizes.I would get one of those and see if it fits the undamaged plug hole first. I think most plugs are a standard thread size.

Ops I just seen your above post.