cutting into cast manifold

[presterone]

I am going to run an external waste gate on my FP manifold. What should I use to cut out a good sized hole in cast iron? I assume a hole saw bit won't even touch it.

 

[EHmotorsports]

You will need some good drill bits and drill a hole big enough to get a steel cutting die grinder and grind away. Or pay a machine shop to cut the hole. Just make sure you taper the edges of the hole so it doesn't promote cracking.

 

[JNR]

yeah, some nice rotary files should work well, when used with a die grinder...they make all sorts from straight to rounded to ball and if you were to use a ball or rounded type to start the hole (putting it at an angle) and work your way down by changing the angle closer to 90 as you get towards going thru...then start rounding out the hole. Just be aware these are not meant to "plunge"; meaning you only want to be cutting one side, so to speak, if that makes sense.

I agree with what was mentioned about though to start with a drill bit first though, then do the above procedure....being it's rounded, take a sharp, small punch and tap it against the runner, so your bit has somewhere to bite and not walk. Don't go overly fast on it and use oil/lube to keep the bit cooler and sharp.

Anyhow, when I did my porting on my manifold and turbine housing those things cut thru the metal pretty quick and once you get the hang of it, fairly accurate, although you'll want some other types like flappers to smooth it out when you're done (although this isn't super critical since you're welding and not porting/polishing).

 

[presterone]

That makes sense. Thanks, one thing I am confused about though is the angle. Do you mean grind the hole so the inside is beveled?

 

[JNR]

I mentioned the angle only for the beginning(s) of the cut(s) since the rotary file is designed to cut from one side and not plunge...so, once you have a large enough hole so that the bit is only cutting from one side of it, then you can do a perpendicular cutting, or opening of the hole. Hopefully that makes more sense.

One thing I forgot to mention and it may be obvious, is use safety googles, or the type that cover all around your eyes (incl. the sides), and/or use a face mask...those little bits get HOT and you certainly don't want the dust in your eyes.

 

[presterone]

Also could someone send me a picture of a modified 02 housing for ex. Wastegaste in a galant that still has power steering and alternator in stock location? I requested this in a previous thread but a close up for inspiration would be nice.