bore and retap screws on RH engine cover for 82 110

[edge]

The screws are not coming out and I have tried everything. What size should I use to drill out and tap the new bolts?

[Dirtcrasher]

If you have to fix them the best way is a helicoil kit - very simple to use and it will fix any thread the same size if you ever need it again. But about 35$ for that size metric.

But if your doing "discount ATC repair" I believe you have enough meat there to tap those out to either a 1/4 28 fine (odd thread to find) or a 1/4 20 coarse thread - .250 inch - which uses a #7 drill or around .200 of an inch. Standard sizes are probably easy for you to find and deal with.

Most important part is to center punch and drill perfectly in the center - usually a 1/8 drill is great for getting a nice straight hole in something before you go larger.

[edge]

how does a helicoil kit work and where can I get one?

[smokinwrench]

how does a helicoil kit work and where can I get one?

It is probably the best thread repair that you can get. You can get them at any auto parts store.

It is actually just a thread insert. You drill out the hole to a specified size. Then you run a thread tap down the hole (tap is supplied with the kit). Then you install the helicoil (it looks like a streched slinky). Breakoff the install tab remove it from the hole and your done. First one might be kinda hard but once youve done a few it only takes a couple minutes to repair any broken bolt.

Sharp drill bits are a must when it comes to drilling out bolts and screws.

I have found that left handed drill bits will remove bolts most of the time.

Good luck