Chasing threads and thread size of manifold bolts

[chaka]

I have a lot of rusty bolts and nuts. I just picked up a used craftsman tap and die set, but I have never used one before and was looking for any advice on the proper way to chase threads....

Also, if anyone knows the details of the bolts that attach the manifolds to the block....

Thanks for the response

 

[thecrazygreek]

10mm x 1.5 IIRC

Chasing threads requires some good rust buster like PB, and making sure everything is squared up.

I chased most all of the threads on my 69 after removing busted old rusty bolts.. what a PITA...

 

[chaka]

SO, as long as I am square, should i be worried about messing up the threads on the inside of the block? also do the block holes take a different tap (one that isn't funnel shaped?) or is it okay that the last few threads won't get cleaned....(and aren't they most important?

seems to me that could be a problem. Also, do you lube them up before chasing them? or soak them first? or just coat it so that the taps and dies work better?

 

[Poser]

if anyone knows the details of the bolts that attach the manifolds to the block....

Six studs, not bolts, 10mmx1.25 are used to retain the intake and exhaust manifold to the head of an F engine 1969 and later.....

SO, as long as I am square, should i be worried about messing up the threads on the inside of the block? also do the block holes take a different tap (one that isn't funnel shaped?) or is it okay that the last few threads won't get cleaned....(and aren't they most important?

seems to me that could be a problem. Also, do you lube them up before chasing them? or soak them first? or just coat it so that the taps and dies work better?

Ideally, you would use a 10x1.25 bottoming tap to get to the threads in the bottom of the holes in the cylinder head....


Just spray down what you want to run the tap or die into or over....

 

[chaka]

Steve,
very good points... I should have noted that my studs have become bolts (Studs with nuts locked on) which is why i was thinking of them that way. I was thinking of replacing the studs, but thought that the wear on the studs and the cylinder holes will probably have worn similarly, so is it better to keep the originals if i don't have a bottoming tap?

 

[Poser]

Steve,
very good points... I should have noted that my studs have become bolts (Studs with nuts locked on) which is why i was thinking of them that way. I was thinking of replacing the studs, but thought that the wear on the studs and the cylinder holes will probably have worn similarly, so is it better to keep the originals if i don't have a bottoming tap?

I would remove the nuts from the studs, and verify that the studs are re-useable. If they are questionable at all, I would replace them.

New studs are better than old studs with nuts seized on them.

 

[igotta40]

A word of caution: don't try to thread the tap in as if it were a bolt. What I do is go about a quarter turn at a time into and then back out of the threads to break loose any junk. Gradually work the tap that way 'til it's all the way in. If there's a lot of rust and dirt you may have to back the tap out and spray it and the threaded hole to wash it clean then go at it some more. That would be the case, for example, if the threads were left exposed with no stud threaded in over a long period of time. After a few times you'll get a feel for how the tool works.

 

[chaka]

is there a good way to remove existing studs other than the double nut method ? how about putting new studs in? is the double nut method used there as well?

 

[cruiser_guy]

A word of caution: don't try to thread the tap in as if it were a bolt.

That means DON'T torque it much at all!! Taps break really easy and getting out a broken tap will be your worst nightmare come true!!