king_doodle

Many of you gurus probably already know this idea I stumbled onto today. If so, I applaud you. Hopefully this could help someone, though. A few weeks ago, I had a heckuva time getting the last bolt out of my right side exhaust manifold. I finally got it out, but fast-forward to today, that same hole would not take the 3/8 header bolt for my new manifolds. All the other bolts threaded up perfectly, but not the rascal over the #4 spark plug. I spent a good 2 hours trying various ways of getting the bolt to go into the damaged hole. After considering my options (heli-coil, re-tapping the hole, turning the hole into a stud, etc) I decided that maybe I could modify the bolt. I took an old file, laid it flat on a table, and filed a chamfer around the tip of the bolt. You can see it in the photo. Voila, the bolt went in the hole and threaded up just like all the others. So the next time you have a bolt that won't catch threads, consider putting a chamfer around its tip.


You can see the chamfer around the tip of the bolt. This was the key to getting it to thread into the damaged hole.

oldcutlass

I usually chase the threads with a tap.

king_doodle

That would be a perfect first step, Eric, except that in a 66 B-body there's about an inch between the hole near the #4 spark plug and the bolt from the control arm. It's impossible to chase the threads without taking the control arms apart.

Olds64

That's a good idea!

OLDSter Ralph

I sometimes use a "Uniflute 90 degree" tool lightly on threaded holes, where possible and check with a bolt. Champfering the end of the bolt works too. It doesn't hurt to have a small "3 cornered" (triangular shape) file for dinged threads or to run off the end to remove slight burr from champfering. Its nice to mention these tips for others who may not know. There are new people who come and read. Thank you for bringing it up.

king_doodle

Thank you, Olds64. I appreciate your kind support.

Those are super additional tricks, Ralph. It seems that a chamfer can overcome a lot when irregularities are present. I'm going to find one of those triangular files that you mentioned. Thanks!

OLDSter Ralph

King, get one that is small enough to fit clear down to the bottom of the V. Pulling it around a bolt and off the end thread will keep a bur from hanging up a bolt. Get a good brand file and handle. I prefer Nicholson. Good luck.

Ozzie

It's another approach to keep in mind when doing such work. The principle is similar to taps & self threading bolts. Different approaches can be helpful depending on the circumstances. Whenever I can, I try to clean up the threads with a tap or thread chaser. You're lucky that they all came out without breaking. Another thing that helps the next removal is using anti-seize on the threads when installing. Thanks for the tip for the forum members.

king_doodle

Ralph, I will definitely look for Nicholson. 'Thread management' is almost an art form. Thank you.

Ozzie, you're exactly. One of the bolts nearly didn't come up intact. The new header bolts have a generous helping of copper anti-seize. For gaskets, I used Percy's Seal-for-Good aluminum gaskets, with Permatex copper on both sides. Next time around, I'm going to check all bolts holes before actually beginning an install.

m371961

I have pointed bolts for years on a grinder.
I have used triangle files to straighten threads, but a better choice is a actual thread file. It is very useful to repair spindle threads, steering shaft threads, etc. It has the correct pitch and thread count.
http://www.sears.com/search=thread%20file%20tool

toymobile

Best advise DON'T TIGHTEN ANY BOLTS UNTIL ALL ARE STARTED.

Johnny

m371961

X2

ronskal

Good idea, have done it myself but your file job on the bolt is a lot better than I can do- especially when I am pissed off at the bolt.

king_doodle

Thanks, Patrick. I'm going to also look for a good thread file. I appreciate the link.

Johnny, you're exactly right. Get everything threaded up first. I think in this case I was thrilled to just get the manifold in place.

Ronskal: The bolts I was pissed off with were these b*stards. At least none of them busted on the way out. :-)

m371961

Your welcome. I have 2 that have saved me many times when a wayward hammer struck threads. They are even made for pipe threads. The square ones cover 8 types of threads, and are easy to use as you can line up on 2 good treads and repair the 2 next to them.
Looking closer, the KD ones look close to what I have, but the discription is for metric, and I doubt that is the price for 3.
Here is a link to a SAE one.
https://www.toolsource.com/individua...h-p-71150.html

m371961

Here is a set that would cover all.