thermocouple questions

[lariat 7.3]

the one comming with the gauges i ordered is the threaded one that screws in i believe. could i just use a regular stainless clamp,drill a hole in it and use it to mount it?

[SmokeyWren]

Why not do it right? Drill and tap a hole in the exhaust manifold, then screw in the new thermocouple.

Of course you can use shade-tree tricks to convert the screw-in thermocouple to a clamp-in thermocouple. But why bother? Home Depot and Lowes and any decent hardware store sells the right-size drill and tap set for a few bucks, if you don't already have one. Drilling and tapping the cast iron exhaust manifold is easy.

[lariat 7.3]

just a question. what about the metal shavings? i was planing on removing the up pipe to put it in there and not worry about the shavings.

[Matt0987]

I got mine from Bully Dog w/ the triple dog and outlook. The instructions, which are both in the supplied booklet and online at their site, tell you the advantages of the before and after turbo locations. I put mine before. I bought the specified tap with it's accompanying drill bit, no need to skimp by using an old bit or tap- a mistake here would mean piles of headaches- laid under the truck, drilled a pilot hole, drilled the actual hole, taped the hole, crawled out from under the truck and started the engine to blow out any metal shavings- expecting that the hole was the area of least resistance and the air would go out of there before it went to the turbo, thereby keeping the shavings away from the turbo and the inside of the engine- then I crawled back under the truck and installed the pyrometer.

It did take some time, no need to rush, but the pipe was easy to drill and tap.

Keep the drill bit and tape well oiled. 3 in 1 oil works well.

[Matt0987]

You know, if the drill and tap process doesn't work you can always return to the shade tree process. You are going to have to drill a hole anyway. Just drill the proper sized hole. Just take your time.

Oh, and when you buy the tap buy a proper size tap handle, too. It will make the process easier.

[Cavitation]

Just installed one yesterday. The drill and tap took about 15 minutes. The clamp on often leak exhaust and are somewhat sloppy in my opinion. Always use the screw and tap ones if possible. Use some heavy wheel bearing grease on the drill tip and tap to keep shavings to a minimum. Use a powerful shop vac right up to the hole afterward which will pull any shavings back out. Just take it slow. Use a new bit and tap as someone else mentioned. Some have broken taps by forcing them. Good luck.

[SmokeyWren]

Originally Posted by lariat 7.3

just a question. what about the metal shavings?

No problem.

Crawl under the truck with your head under oil filter. Look up to where the up pipe connects to the manifold. Drill the hole in the manifold about an inch from the flange for the up pipe. You'll be drilling almost straight up. The drill dust/shavings are going to be falling down into your eyes, so I hope you wear good googles. But unless the laws of physics have changed, not too much of the drill dust is going to fall up.

Even if a little bit of the drill dust winds up in the manifold, it won't hurt anything. When you first crank the engine, the dust will pass through the turbo before the turbo gets to spinning very fast. So it will pass right on out the tailpipe with no harm done.

[Scraph]

My 2 cents on getting this hole drilled and tapped if you're concerned about shavings (and you might as well be).

Locate the hole on the lower half of the drivers side up-pipe flange. This will give you the thicker portion of material to work with. (Easier to machine properly and will provide a stronger, better seal)

Start with the smallest bit you have and run up through the set (just grow the hole one size at a time). Don't use any oil or WD-40. It isn't really necessary if you drill the hole open gradually. Drilling dry will keep the shavings dry and they will vacuum up much easier.

For tapping the hole, I highly recommend finding at 12-point socket that fits the tap. A 10mm 12-point socket fit my tap very well. Put a good sized extension and a ratchet on this. It is very important to keep one hand around the extension/size/tap to get rid of all the unwanted forces on the tap since you're using a ratchet instead of a T-handle. I recommend this method because you have more mechanical advantage and are working more comfortably. As long as you make sure to use your holding hand to take out all the side loading, this will be a better method. No chance of screwing up the process if you're not straining to get your hands up there or struggling with not enough mechanical advantage. Like usual, drive the tap in a few turns and then periodically back it out about a half turn to clear out any shavings. Since you're using a tapered pipe tap, periodically check the fit of the thermocouple. When finally installed you want the thermocouple fitting to have a thread or two protruding into the manifold. Make the threads tight enough to accomplish this and still seal. Use anti-seize on the threads to installed.

Vacuum the hole out when satisfied with the tap.

[Matt0987]

Start with the smallest bit you have and run up through the set (just grow the hole one size at a time). Don't use any oil or WD-40. It isn't really necessary if you drill the hole open gradually. Drilling dry will keep the shavings dry and they will vacuum up much easier.

The oil saves the bit and the tap.

It allows the cutting edges to cut easier. It reduces the chance of a break of both a bit and a tap. You do not want either to break off. Then you will be spending hours cussing and fighting the broken tools. Keep your blood pressure normal. Use the oil.

Do not force the tap. As said before.... Cut a little thread, back off, (at this point I like to add a little more oil) and cut again. Repeat this process a little at a time until the threads are cut through the metal.

If you are using a wrench rather than a tap handle be careful of the additional torque the wrench provides. Taps are made of hardened steel and will snap "easily". Depending on the size of the tap. Their material makes them nearly impossible to drill out if one snaps off.

[Scraph]

The point of my post was how to make dry machining safer to aid in the removal of shavings afterwards.

Cutting fluid is _not_ an absolute requirement for any machining operation. The purpose of a cutting fluid is to provide cooling and lubrication. The lubrication is desirable to lessen friction between the tool and the material to ... lessen heat generation. The whole point in cutting fluid is to control temperatures of the tool and the material being machined to 1. lessen weakening of the tool due to excessive temperature (causing metallurgic properties to change) and to 2. prevent dulling of the material by welding of the metal shavings onto the tool itself.

Believe it or not ... the majority of torque required to tap a material is going to be from actually cutting the material ... and not from friction because you're not using WD-40. In fact, because the relative motion between the tap and the material is so slow and minimal (and substantial heat is removed as the chips fall away) there isn't very much friction generated heat coming from this manual tapping operation (at least not the friction that a cutting fluid could help with). Besides, dry machining is actually common practice on cast iron.

Long story short ... giving a periodic spray of WD-40 to the tap while machining may make you feel better about yourself but it's not by any means a requirement of the operation ... and in an instance where it is important to be able to remove chips and they are easily removed when they remain dry ... there is no good reason to use cutting fluid for this operation.

As for the comments on using a ratchet versus the standard T-handle ... I agree it allows more mechanical advantage. I also agree that tool steel is hard and therefore brittle. If the individual performing this operation doesn't have enough mechanical sense to understand the precautions and how to safely use these tools ... maybe he shouldn't be doing it himself in the first place?

A ratchet can very easily be made to strip the threads or shear the head right off of a bolt for any piece of hardware he tightens ... so should he instead then only allow himself use of his fingers? Proper use of any tool is a given. That's why not everyone is a very good mechanic.

[MonteC]

I liked diesel manors instructions the most. What scraph posted is pretty in line with them.

Im also for dry cutting in this situation. The cast iron manifold wont be a big problem for a quality drill bit. And you wont break the drill bit unless you just have no clue how to use a drill.

Keeping the shavings small and dry is the best way to go in my opinion.

[Matt0987]

Lariat 7.3

You have a couple of differeing opinions as to how to do this. Good luck.