Drilling and tapping exhaust manifold

[LRutigliano]

Thanks to all your replies on the gauges. I ordered the DiPricol 3 gauge set with the A-pillar mount.



- Boost gauge will use port in AFE Bladerunner.

- Trans temp will use sender extender in test port of 48RE.

- Pyro: do I go post or pre turbo?



Post turbo looks very appealing. I can drill and tap from the bottom of the truck into the elbow coming off the turbo. Chips fall onto ground and no turbo to worry about.



Pre turbo seems like a better temp of EGT, but I am FREAKED out about drilling and tapping into the exhaust manifold due to chips getting into the turbo. I've read about using a shop vac while drilling and tapping and not using grease because it will trap chips.



What did everyone else do? Looking for reassurance and advice on the pre-turbo drilling and tapping or concurance that post turbo will be fine.



This single mod has me all "pinched up", please help... :{



Thanks,

Louis

 

[Hoefler]

Shop vac while drilling, grease on tap, cleaning and re-applying grease a couple of times during tapping. Any pieces that may have fallen in will be blown through before turbo has a chance to spool up and out.

 

[SSalzer]

I used to have mine post turbo. I moved it pre when I was installing my Pacbrake. I can not believe the difference in the readings between the 2 locations. I would definately recommend placing it pre-turbo.

I had the engine running while I was drilling and the pressure from the exhaust blew the drillings right out of the hole. Never had a problem. It's really not as big of a deal as you might think. Just go for it!

 

[Jetpilot]

Drilling while the engine is running is they way I have done it for years. Be sure and wear eye protection you wouldn't believe the pressure inside the manifold even at idle.

 

[steved]

Drilling while the engine is running is they way I have done it for years. Be sure and wear eye protection you wouldn't believe the pressure inside the manifold even at idle.

This is how I did mine as well... make sure you go very easy on the drilling as you can easily "break through" the last bit of material.



I used never-seize on the tap when I did mine (it handles the heat better)...



steved

 

[Joseph Donnelly]

I recommend having the engine cool, shut off, and putting the probe pre-turbo. On third Generation turbo diesels, we have an easy place to drill and tap for the probe. Drill from above into the horizontal leg of the exhaust manifold just rearward (toward the firewall) of #3 exhaust passage. Try to keep chips out and remove them with a magnet before breaking through into the exhaust passage. A few chips may get inside, even using grease on the tap. A small magnet on a telescoping stick will fit into the 11/32” (for 1/8 NPT) or 7/16” (for ¼ NPT) hole you drilled, and you can move it around and collect the chips easily. Tap progressively deeper until your probe fitting can be threaded in about 4-5 threads.

 

[RRees]

I did what Joseph Donnelly recommended to my truck.



Yeah I was freaked out. But no problems, 15K miles later.

 

[CumminsBu]

Thousand have done it with no ill effect. The shavings are so small it would hurt any thing. I was more worried about breaking a drill bit or messing up the threads.

 

[MasterChief]

Personally I look at that turbo as a small jet engine. Just thinking about the chance of metal shavings or a single metal shaving moving through something that is turning at such a high RPM kept me from going pre-turbo. If you even get a small nick on one of the blades the turbo will slowly start to FOD itself out. And over time (shorter than normal) it will it will fail. The purpose of the temp gage it so you can have a relatively good idea as to what your turbo temp is, post or pre; same thing just a different reading scale.

Ten people ten different reason; mine safety and $$



Mike

 

[LRutigliano]

Joseph Donnely,



Thank you for the very ingenious magnet tip. It is so simple, yet so brilliant! My dad is a retired auto mechanic and he always had tips like you. However, I hate to ask him because his reply always starts with "why cant you leave stuff that is not broken alone!!" and then after a long time of ranting/raving I get some suggestions...



Thanks to everyone else for the replies and confidence.



Could I request some pics posted of your thermocouple install just to ensure I am drilling in the correct location(s).



Regards,

Louis

 

[MDTyree]

I took the exhaust off the down pipe, the boost tube off the turbo and the intake, and unbolted the turbo, covered it with tape and moved it out of the way. I think that would be the safest. It took my brother and I about 2hrs. I put it in the back port of the manifold.

Good Luck

 

[Joseph Donnelly]

The location of the probe is not critical. I wouldn't worry about the probe breaking off or something else causing damage to the turbo, so long as you get the chips out. Clearance of the fins to the housing is not great, so I wouldn't want to take a chance on a big chip getting wedged in there. I have had only one probe failure, and that is from a post-turbo installation when a turbo failure caused the exhaust wheel and shaft to roto-rooter the down pipe and destroy the probe. That just added to the cost and pain of replacing the turbo.

 

[JMichelson]

Location, Location, Location

I'm going to put mine in the conveniently pre-tapped hole in my Jacobs Exhaust Brake. All you are doing by drilling it in the exhaust manifold is in my opinion greatly increasing the odds of messing up the turbo or possibly ruining a perfectly good exhaust manifold. The big difference between pre and post turbo is how fast the gauge responds and the temperature limit you use. I had pre-turbo in my 98 and it worked great for years. I would guess that if you took it to a shop to have the probe installed they wouldn't do it without removing the turbo. I could be wrong. Maybe someone with a shop would chime in and prove me wrong.

I have flown various turbine airplanes over the years and they have different locations for the temperature probes. Some were ITT (interstage turbine temperature) others were TIT (turbine inlet temperature) and others were EGT(exhaust gas temperature). The only thing that we saw as pilots were different temperature limits on the gauge.

If you understand the limitations from locating it post turbo it will be fine. It's risk verses benefits. I'm not convinced that anyone can say thousand have been done with no ill effects. I wouldn't want mine to be the first. Jeff

 

[betterthanstock]

. The big difference between pre and post turbo is how fast the gauge responds and the temperature limit you use.

Depending on low or high boost, your actual engine out EGT will vary. At low boost, less difference, at higher boost, more difference. I think the guage is too slow ahead of the turbo, so even slower would only be useful on very long hills, where you hold power steady.



I too was concerned, but by drilling it on the flat, where chips cannot fall in, and then using the magnet several times, in all directions, I took out all chips. I then started and idled it, then revved it up to 1000, 1500, 2000, and so on, to blow every thing out before the turbo hit any real rpm.

 

[Jack in Alaska]

manifold taping

Have the engine idling when you break through with the bit and while you are tapping the hole. Works great.

 

[BHolm]

I'm going to put mine in the conveniently pre-tapped hole in my Jacobs Exhaust Brake. All you are doing by drilling it in the exhaust manifold is in my opinion greatly increasing the odds of messing up the turbo or possibly ruining a perfectly good exhaust manifold. The big difference between pre and post turbo is how fast the gauge responds and the temperature limit you use.

Yep, and the closer to the source of heat, the quicker the response and more accurate dipiction of the temps involved. Very good reasons to go in the manifold.

I'm not convinced that anyone can say thousand have been done with no ill effects. I wouldn't want mine to be the first. Jeff

Thousands HAVE been done with no ill effects. If somebody had lost a turbo due to an EGT probe installation in the manifold, trust me, it would have been plastered all over this site, and that of the other TD sites. I have never heard of such an issue, can you show me an example?



I had the probe in the exhaust brake elbow on my stock '06 Mega. I have it in the manifold of my '06 QC. There is a pretty big difference, and if you are seriously concerned about damage, the turbo is probably a lot less expensive to replace than melted pistons and all that come with that failure.

 

[JMichelson]

BHolm
I was thinking more of metal shavings going into the turbo and damaging the blades there is very close tolerances in the the turbo and even a small chip could damage it. Can I cite an example, No. I'm just pointing out that the risk is there.
Thousands HAVE been installed post turbo with no ill effects. You just have different limitations. If you manage to melt pistons you have exceeded the limits and it doesn't matter where your probe is stuck.
Jeff

 

[BHolm]

BHolm

I was thinking more of metal shavings going into the turbo and damaging the blades there is very close tolerances in the the turbo and even a small chip could damage it. Can I cite an example, No. I'm just pointing out that the risk is there.

Thousands HAVE been installed post turbo with no ill effects. You just have different limitations. If you manage to melt pistons you have exceeded the limits and it doesn't matter where your probe is stuck.

Jeff

... and a bus could run you over tomorrow crossing the street, doesn't keep you from doing it though.



I don't think a very good argument can be made against putting the probe as close to the heat source as possible. There is a risk, there is risk in everything you do. This is an extremely small risk and unless you seriously botch the job, you have nothing to worry about. The metal shavings are pretty small. Only a moron would let the big ones get by, the small ones will blow through without issue. Like I said, it has been done a thousand times, no reported issues I have ever heard of AND pre-turbo is undoubtably the better place for the probe perfomance wise.

 

[Grey Wolf]

When I drill the manifolds I magnetize the drill bit and tap, everything sticks to the bit and the little bit that gets by is picked up by putting the bit down into the manifold... .

 

[betterthanstock]

I think the people who do it with the engine running are actually at much greater risk of damaging something, or getting injured on the hot manifold.



For one, the exhaust has pulses, so the chips can be sucked in, as well as blown out. They can even be sucked up into the cylinder, then spit back out. When you drill a hole into the side of a pipe carrying a fluid at high speed, it may also cause a suction at the hole due to a venturi effect. It varies with where you drill it. I still think the safest is to have the motor off, then use a magnet inside the hole, until there are no more chips coming out.