Manifold Vacuum Port

[gedoane@bellsouth.net]

What is the tap size for the vanifold port?

The plug was frozen and I had to drill it out. I need to acquire the correct tap to operate my windshield wiper.

Thanks, Gary

 

[The Master Cylinder]

⅛"-27 NPT - pipe thread

 

[Y-Blockhead]

One of the big tools I will miss when Bratton's closes their doors is their on-line catalog. They list the thread size of all the fasteners in the listings.

I suggest you all save your paper copy of Bratton's Catalog for this great resource.

 

[JayJay]

What is the tap size for the vanifold port?

The plug was frozen and I had to drill it out. I need to acquire the correct tap to operate my windshield wiper.

Thanks, Gary

Depending on how you drilled it out, you may need to go up a size on the pipe thread and use a reducing bushing. The proper drill size for 1/8"-27 pipe thread is a letter "Q" drill (0.332"), which is just a hair over 21/64" (0.328") but less than 11/32" (0.344").

Be sure you take your carburetor off before you drill or tap into the manifold, it will prevent chips from going down inside.

 

[KMBeers]

As a follow on to what JayJay said I would have a helper hold a shop vacuum over the open manifold bore to make sure the chips go the right direction while you are drilling and tapping the hole. Maybe a bit of an overkill but better to be safe than sorry…..

 

[nkaminar]

Since the tap is a tapered pipe tap, the depth of the tap determines how deep the fitting will go. Tap a little then try the fitting. If the fitting does not go in deep enough tap some more and try again.