Helicoil issue in head stud hole.

[john worden]

Attempting to install Helicoil in head stud location. After drilling with the supplied drill, the supplied threading tap will not engage to start cutting threads. The block is in the car and I lubricated the drill and tap with cutting oil. We tapped lightly on the tap while turning it, but it will not engage. Any thoughts appreciated. Thanks. John

 

[Charlie Stephens]

Would it help to chamfer the hole?

Charlie Stephens

 

[Synchro909]

I think a steady downwards pressure while you turn the tap would be better than "tapping the tap". If you chamfer the top of the hole, don't go overboard. Chamfer a little, try it and if you don't get anywhere, chamfer it a little more till you succeed. Personally though, I wouldn't chamfer it.
PS. It is important that the drill and tap are kept perpendicular tot he top of the block or the stud will not line up with its hole in the head.

 

[johnneilson]

Typically machining cast iron is done dry, no lube

J

 

[Y-Blockhead]

It is important that the drill and tap are kept perpendicular tot he top of the block or the stud will not line up with its hole in the head.

I agree. I use a tap guide similar to this one to ensure the tap is pertpendicular to the top of the block (or whatever you are tapping https://www.amazon.com/GATOR-TOOLS-V-Tap-Guide-Standard/dp/B000ZN30U4/?tag=atomicindus08-20

 

[Bruce of MN]

This was my experience:

https://www.fordbarn.com/forum/showthread.php?p=1997462&highlight=insert#post1997462

 

[nkaminar]

Synchro has a very important point. The Helicoil must be in the proper location and perpendicular to the block. I have used an old head for this, bolting it to the block and enlarging the hole where the Helicoil tap is used just enough. The head can still be used on an engine with the enlarged hole, if necessary.

I agree that a steady strong pressure is needed to start the tap. I also agree that the hole should be tapped dry. Tap a little then back out a half turn to clear the chips, then continue. Repeat to back out as you tap to continue to clear the chips.

 

[Terry Burtz Calif]

Helicoil taps come in plug and bottoming styles.
If you are trying to start a threaded hole with a bottoming style tap, it is very difficult.

 

[john worden]

Would it help to chamfer the hole?

Charlie Stephens

Worth considering. Thanks.

 

[john worden]

PS. It is important that the drill and tap are kept perpendicular tot he top of the block or the stud will not line up with its hole in the head.

We did make and use a guide for that purpose. Thanks.

 

[john worden]

Typically machining cast iron is done dry, no lube

We will try that. Thanks.

 

[john worden]

I agree. I use a tap guide similar to this one to ensure the tap is pertpendicular to the top of the block (or whatever you are tapping https://www.amazon.com/GATOR-TOOLS-V...3351856&sr=8-5?tag=atomicindus08-20
Thank you. John

 

[john worden]

This was my experience:

https://www.fordbarn.com/forum/showt...rt#post1997462
Thank you. This looks promising. John

 

[john worden]

This was my experience:

https://www.fordbarn.com/forum/showt...rt#post1997462
Thank you. John

 

[Phil Brown]

Agreed with Terry, trying to start a bottoming tap in a freshly drilled hole is tough to do. might also check that the drill is the correct size for your Helicoil, even if it came as a "kit" things happen in packaging

 

[john worden]

Agreed with Terry, trying to start a bottoming tap in a freshly drilled hole is tough to do. might also check that the drill is the correct size for your Helicoil, even if it came as a "kit" things happen in packaging
Will check again. I know it isn't a bottoming tap. Thanks. John