Tapping aluminum intake

I need to tap an intake for a larger intake air temp sensor. 

Bought a bit and tap off Amazon 

Anything special to worry about? I read somewhere that aluminum doesn't cut cleanly

Cast aluminum machines quite easily. Use a tapping fluid if you have it, if not use a light oil.

Don't go too deep with the pipe tap or the thread won't do what it's supposed to do. You can always test it and go deeper if need be.

The softer the material, the lighter the oil.  WD 40 or PB blaster works well for cast aluminum.

You'll know when you're done if the tap was sharp.  A good sharp tap will leave clean threads.  A poor tap will leave it galled.  It's fine either way.  The threads are basically there to provide outward force against the tapered hole.  Might make a difference in how much pipe dope you use.

Thanks,

Wanted to check since I only have one part, so need to get it right on the first try!

Are you doing it in situ?  Got a plan for any shavings getting inside?

In reply to Stampie :

No, will be pulling it to drill and tap. Don't need shavings inside the motor! 

In reply to sevenracer :

Something that I've noticed, especially with aluminum, is that reversing the tap a little every quarter to half turn loosens the shavings and makes the tap go in smoother.  The light oil also helps.

JoeTR6 said:

Something that I've noticed, especially with aluminum, is that reversing the tap a little every quarter to half turn loosens the shavings and makes the tap go in smoother.  The light oil also helps.

Yes.  Don't let the tap get bound up in the hole from the swarf.  Back it out frequently to clear them out as you go.

If possible, use a drill press if only to ensure the tap goes in straight.  At least center the hole under a drill chuck and use a small pointed shaft to make the first few turns square.  DO NOT use Tap-Free, a lubricant for tapping holes but it will just eat up  aluminum.  Use a drill a tad smaller than specified for tapping steel, you can always take more out.

sevenracer said:

In reply to Stampie :

No, will be pulling it to drill and tap. Don't need shavings inside the motor! 

Good plan.  I have seen people do this sort of thing (at the track) buy putting grease in the hole and hoping it catches the swarf and that they can also get it all out after you withdraw the tap. Makes me veeeery nervous!

I would drill a pilot hole first then use the tap drill. That way it insures the tap drill doesn't wallow around produce an oversized or out of round hole.

pirate said:

I would drill a pilot hole first then use the tap drill. That way it insures the tap drill doesn't wallow around produce an oversized or out of round hole.

He is tapping an existing hole larger if I'm judging the picture correctly.

I was advised a long while back that gear oil makes a dandy cutting fluid for aluminum. 

Really, any kind of oil is better than none.  I have heard that ethylene glycol coolant is also really good on aluminum, have not tried.

The key is not so much the lubrication of the cutting tool so much as keeping it from sticking to the cutting tool. That way lies galling and despair.

I did some heavy duty hand cutting on an intake manifold when I was advised the gear oil.  Wow! Never had chips stick to the tooling after that.

It's done. Was uneventful, galling and despair avoided. I used a drill press to drill the hole, but hand tapped with wd40. Backed it out and cleaned the chips off a couple of times. 

Glad you had success!

AL is about the only time WD40 works ok. On steel, WATER is actually better! (But the right cutting cutting oil is better than either)

I just realized that was the intake elbow on a Turbo II and not a water outlet.

If you use a GM style air thermistor, the vibrations may break it, and it may get heat conduction from the inlet elbow to skew the temp one way or the other.  It's probably best mounted threaded into a plastic elbow rather than aluminum.

Worst case, it doesn't work and you can plug the hole with an NPT plug.  Assuming that "doesn't work" doesn't lead to a broken engine that is - I have heard of Ecoboost swaps failing because they threaded the temp sensors into metal, causing the temp reading to skew, causing the engine to run lean, causing the pistons to become high-flow crankcase breathers.

Well dang, now you tell me!

It's a Haltech sensor, I'm sure it's something common, like a GM piece. I figured stock location was a good place. I'm planning to use the stock top mount intercooler, so will have to think about where else it could go.