Drilling the head

[BigD]

This kinda belongs in the DOHC section but it's more about the skill than the specific application. It feels to me like the cleanest solution for adding the 2nd temp sender to an M52 engine is to drill the boss in the head but I just can't get my head around how you can possibly expect to do this without getting shavings inside the coolant passage. I can see being careful helping to control the ones that come out from going in but there will always be a bit of shit that ends up on the other side when you punch through... right?

Any input from experienced machinists/drillers would be highly appreciated. I want to do it this way but it really scares me...

[Jean]

Do it with the head out of the car maybe ? or have a vacuum nearby at the drilling point ?

[BigD]

Do it with the head out of the car maybe ? or have a vacuum nearby at the drilling point ?

Well the engine's currently on a stand. I don't really want to take the head apart as I don't trust myself to put it back together properly. I could rotate it on its side, and drill up. But even with a vac, when you push through the hole, some shavings will be inside, I don't know if they will get sucked out...

[StereoInstaller1]

If the motor is on a stand, seems to me it would be fairly easy to thoroughly flush the motor with water.

Any tiny particles are just gonna get stuck in the radiator, I would think.

Either way, git it done!

Luke

[trent]

use grease on the bit as i told you..works perfect. :)

[LINUS]

use grease on the bit as i told you..works perfect. :)

That'a a good start, but what really worked for me was to take my wet/dry vac, put on that crevice tool, and then duct tape a 6" piece of drinking straw in the end of that, leaving 3-4" showing, and duct tape the end up so the only air moving is thru the straw tip. I got every last shaving that way. There's a big ledge inside the head where you are drilling about 3/4" inside from where you drilling, and if you make your head surface flat & level, the shavings all land there where you can easily see them, and none of it gets further down in the cooling jacket. After you are done you'll laugh how easy it was, and how much people around here make a huge deal out of nothing.

If you never tapped something before, use plenty of lube (grease is fine), and once you get a solid start (2-3 full threads/turns), then go forward a little, back off, forward again, back off - don't just mow forward. You get good clean threads that way.

[BigD]

Cool, thanks guys! I think I'll give it a shot. Can you tell me what thread size the sensor is (the brown one I guess)?

[LINUS]

Cool, thanks guys! I think I'll give it a shot. Can you tell me what thread size the sensor is (the brown one I guess)?

Not offhand, but it's got to be somewhere in the stickied 24v thread. Also, since you are new to tapping, when you search and find the thread pitch, you go buy the right tap and on the package will state the final bit size to use. I say final because you want to use a punch to locate the hole, use a fairly small bit to get your pilot hole, then either one or two steps to the final bit.

Do not cheap out on the right final bit size. It (bit size) determines the effort required, and also the final thread quality. I want to say the final bit was a 13/32" - but I really don't remember. Just buy a new, proper sized bit.

[BigD]

Not offhand, but it's got to be somewhere in the stickied 24v thread. Also, since you are new to tapping, when you search and find the thread pitch, you go buy the right tap and on the package will state the final bit size to use. I say final because you want to use a punch to locate the hole, use a fairly small bit to get your pilot hole, then either one or two steps to the final bit.

Do not cheap out on the right final bit size. It (bit size) determines the effort required, and also the final thread quality. I want to say the final bit was a 13/32" - but I really don't remember. Just buy a new, proper sized bit.

Thanks Linus! I'm not actually new to tapping but I've drilled and tapped enough holes to know I suck. I can't drill straight for shit. :( But I'll try very carefully this time, with some help to monitor the drill angle.

13/32? The sensor has sae threads? Anyway, I'll try searching the 24v thread.

[BigD]

Is there a place I can stick the sensor on the thermostat housing? That'd be a crapload safer and cleaner. Would maybe have to extend the lead but I have no problem with that. I'd like to add an aftermarket temp gauge anyway, for the oil temp and pressure too.

[LINUS]

Ok, I just went an grabbed the tap I **think** was the one I used, fairly sure, but it's in the thread. Anyhow, my 12x1.5 tap has some aluminum bits left in the flutes, so I'm guessing it's the right one, as I do a lot more in steel than aluminum. I only have a full-feed mig, so mild & stainless are all I use around the house.

12x1.5 takes a final size bit of 13/32.


So since I remembered 13/32 the other day, and my 12x1.5 has a bunch of aluminum on it, I bet that was it.


You really are building this up too much. If you can get the surface flat & level on your stand, it's fairly easy to keep the drill perpendicular to the surface, or use a buddy as a spotter. You're way out-thinking the deal, it's only metal. As long as you do this job before cracking your 1st beer in the garage you'll be just fine. Just punch the location, chuck up a pilot bit, and get to it - you'll laugh at yourself for all the buildup once you are done.

I put a temp sender in my oilpan, and I milled a deal to run a oil pressure sender. If you want pics of what I did, PM me your email addy.

[BigD]

No I know, you're absolutely right, I always overthink my projects. Usually it ends up with things being planned out well but in this case it's not really the drilling that worries me as much as the idea of metal shavings getting inside the engine where there's no way for me to get them out with any kind of certainty... if there are a few tiny ones left, is there any danger in it? I can't really see it screwing anything up, maybe getting stuck in the radiator like someone has already said... I know I sound like an insecure broad but it's my first time doing an engine swap so I'm pretty paranoid about it going right.

And you have PM, pls send me those pics!

Thanks a ton, Linus (is that your name btw, sorry I'm assuming...)!!!