crooked exhaust studs

[catback]

well i got my head back from my builder, i asked him to helicoil the studs and put 7/16 studs. i tried to put my manifold on last night and three studs are in crooked. the manifold wont fit at all:3d_frown:

how can i remedy this.
i'm calling this guy and freaking out tomorrow, just want to know how he should fix it. re-tap? if he does will he need bigger studs?

thanks
Dan

 

[bigaaron]

If you want it done right you gotta do it yourself. (That's why I sell the kits :biglaugh

What you can do is take out the crooked ones, put the manifold on, then try to screw them back in. It's important for them to drill the holes straight otherwise it will turn out like yours. If they are just a little off it will probably be ok. If they are really crooked then the machine shop may need to install timeserts (sp?), but that is even more critical that it's is drilled straight. In fact, there is a drill guide that should be used, or put the head on a drill press to make the holes.

 

[tte]

You could use a bigger helicoil with a bigger sized thread on the outside but 7/16 thread on the inside. That way you could use the same studs.

A good way to make sure you drill and tap the holes in straight is to make a block that you could temporarily bolt onto the side of the head.

On the block you drill the right sized hole on a drill press or bridgeport...that way the hole will be perpendicular to the surface of the block.

Mount this block over the hole position on the head where you want to drill and tap. Using the hole in the block as a guide drill the hole in the head and tap it.This way you make sure the hole you tapped is perpendicular to the exhaust side surface of the head.

Others have used a drill with a bubble.

Cheers,
Roy

 

[catback]

If you want it done right you gotta do it yourself. (That's why I sell the kits :biglaugh

What you can do is take out the crooked ones, put the manifold on, then try to screw them back in. It's important for them to drill the holes straight otherwise it will turn out like yours. If they are just a little off it will probably be ok. If they are really crooked then the machine shop may need to install timeserts (sp?), but that is even more critical that it's is drilled straight. In fact, there is a drill guide that should be used, or put the head on a drill press to make the holes.

thanks for the quick reply:icon_bigg
is it ok to open up the holes on the mani to make it fit aswell?

i knew i should have done it myself. but i was worried about this exact thing happening to me:3d_frown:
i'll try to take the 3 crooked onesout ,put manifold and replace studs.

thanks again

 

[bigaaron]

thanks for the quick reply:icon_bigg
is it ok to open up the holes on the mani to make it fit aswell?

i knew i should have done it myself. but i was worried about this exact thing happening to me:3d_frown:
i'll try to take the 3 crooked onesout ,put manifold and replace studs.

thanks again

I wouldn't drill out the manifold, if they are that crooked when you tighten them down they are going to pull straight which could strip out the threads.

 

[staticpat]

I installed bigger studs on mine while in the car and one came out crooked (tight space + drilling with 90 on drill = bad idea). I just drilled the manifold hole a little bigger and it worked fine. Works in a pinch, but probably not the best idea if the head is out of the car with full access. Also I loctited my studs in, so they wouldn't pull out of the aluminum as easy