3 replies to this topic

[Newbieminiguy]

Hey all first post,

I replaced the head gasket well attempted too as it had failed. When pulling the head i realised the bottom right srud was loose and pulled straight out i can only imagine it had not been put on properly by the previous owner as it was running rough when purchased. So i have attempted to put a helicoil in to fix this and im at the end of my tether i just can not get them to seat into the block properly and im lost for what to do now as i have tapped the block already?

 

Can i got the next size up 7/16?

Many thanks

[carbon]

To helicoil a blind hole you will probably need to use two taps, first is 'taper' (or first) tap to get thread started, and then finish off using a 'plug' tap which cuts the threads all way to bottom of the stud hole.

 

Many helicoil kits come with just a first tap. This won't cut full thread all way and the helicoil is unlikely to fit and work properly.

 

For a heavily loaded head stud the helicoill has got to be done just right, and this is not a trivial job. Also most important to have tap dead perpendicular to the top face of the block when cutting the thread otherwise the head stud will be skewed.

[MRA]

be careful as drilling too deep can result in the blind hole becoming a through hole..... 

[limby2000]

You,ll end up drilling for oil!.