Ok, this is what has happened. I tried tapping the hole on my block above my oil filter for the 89 TPI oil sending unit, instead of using an adaptor for the hole behind the intake manifold. This is where my problems started, I figured out that the thread is a 1/2-20 which i am still not absolutely sure about because it might be NPT. That is problem number one. Problem number two is wehre i was drilling, i had thought it was a solid iron notched cut out, instead i found out it was a plug. The problem is i drilled it out and was not exactly in the center, then when i was done the piece of plug fell down from the top of the hole, meaning i now have a slightly oval hole. I can't tap it because the hole is now too big for my tap.

I'm not panicing yet, but my questions are: Can I helicoil the hole? I still need the correct tap size for the stupid sending unit.

Could I just weld the hole up with a MIG welder? Should I fill it with weld or should i weld a small plate on the front of the hole? By me i mean get it done at a shop.

Thanks ahead of time!!

Matt

 

The hole is 1/4" NPT.

If you drilled through there already, you have real problems on your hands. You now have metal shavings in your oil passages, downstream of the oil filter. Which means that the first time you start it up, they're all going right straight to your bearings. You need to pull it, tear it down, clean out the passages with a rifle brush, and put it back together. And of course, get the remains of the old plug out, and a new plug put in.

 

Its already apart, thats not a problem.

Matt

 

Since it's already apart I would suggest just letting the machine take card of it. They will know the best way to handle it. Just be glad it's still not in the car...