I was digging around looking for the most common method of tapping the manifold for the EGT guage. The results have been quite conflicting. What path did you guys take in your install?
Engine running or not? not a fan of this, I think the vacuum/magnet trick is sufficient.

Grease/lube? Seems like a good idea for lubrication purposes, but dry makes more sense so the flutes of the bit can do their job and send the metal bits out of the hole. As for the tap, I'm just not sure.

Drill bit size? Calls for size R, I have an 11/32 which is awfully close. Good enough or do I need to drive my butt to town and get the R?

My biggest question is really over the use of cutting grease or not. Using the drill bit dry doesn't bother me, but should I lube up the tap?

 

What I did was touse the drill dry, the truck was not running, I did not [ush through, but a slight presure the whole time. The tap I used cutting fluid. Did not want to break a tap and have an exhaust leak.

I believe when I looked into this, eveyone was nearly on the same page and said there should not be an issue with chips as long as it was done slowly.

Good Luck

 

I drilled the up-pipe instead of the manifold, but the process is the same. I did use lube while drilling- use a slow speed on the drill & let it work. High speed & pressure will just burn & dull the bit. When tapping, use lots of lube and keep backing out the tap as you work it in a little further each time. Once you get to about half way in with the tap, I suggest you back it out & test fit the adapter. It's probably more critical to do that on the up-pipes since they're thinner, but you don't want the hole too big. The adapter won't tighten and you'll have leak. Other than that, it's pretty easy. Take your time and you'll do fine. I didn't vacuum anything when I was done. I simply installed the probe & started the truck when done. The shavings won't be big enough to hurt anything and will just blow right out through the turbo & exhaust...

 

Here is a link to a gauge install and has very good pics of the way I did mine and it was easy! Go slow and work tap slow and easy!! Go on the drivers side
easy reach!!

Smokie

http://www.dieselmanor.com/diy/PSD3-gauge/image27-1.htm

 

Thanks for the replies, fixing to dive in. Was looking at DieselManor the other day, they never make any mention of using cutting oil and clearly state not to use any grease. Others here and other sites mention they used grease. Just thought I'd get some more input from the folks here. I am going to lube 'er up!

 

I wouldn't do that !!! Better off dry! If you do the manifold like it shows the metal is soft and drills easy!!

Smokie

 

Lubing won't hurt anything. I used WD 40 for both drilling and tapping. No issues. The lube helps the bit cut + cools it...

 

You don't want to use any lubricant when drilling cast iron as it just makes a paste and slows the drilling down. You can on the up-pipes since it is not cast. At least that is my experience from machining in the past.

 

Well, got called away and never got started. Makes some sense that the cast would paste up with oil. Maybe I can get started on it again tonight.

 

Did mine dry not running no problems.

 

Drilled mine dry too. If you really want to do it right and don't mind spending a couple bucks get the drill bit and tap kit from Clay. You'll still need to start small in bit size and work your way up but you'll know your drilling the exact size hole for tapping. I bought the drill and tap set and I didn't want to booger up anything as I'm good at doing that sometimes.

 

To answer your question about the 11/32 drill bit. It will be just fine.

 

Decided to hit that hole dry.
Got everything done last night leaving the manifold for last. Started tapping it and the tap just wouldn't bite. Worked fine on the aluminum aih delete plug. After a few tries it was clear that the tap was doing more damage than good. The set was my grandfathers and probably 30-40 yrs old. Got a nice Matco tap this morning and it was clearly a better tap. Ran it in no problem. The Matco called for a 21/64 drill bit but I had already hit it with the 11/32, seated just fine though. Thanks for the replies.

 

The right tools aways work the best!!! Good job !!

Smokie