Where to put EGT probe??

[Sledneck]

I am getting ready to install a Pyrometer in my 04 H. O, what I noticed was Cummings moved the exhaust header collector rearward and it now immediately turns 90 degrees down and connects to the turbo mounting housing. On my 02 HO it was in the middle of the engine and came straight out. I guess they didn't have the room for that setup in the new body style. Anyone have the correct location for mounting the probe, My guess would be on the down portion right before it bolts to the turbo housing but I don't know exactly where to mount it. Distance up from the bolt flange? how far right or left? or should it be on the side? This time I will have to un bolt the turbo so gravity doesn't let the shavings get directly in to the turbo.

 

[KLockliear]

You have it correct. About an inch up from the flange, in the back half. Your gauge should come with a picture if it comes from a diesel specific supplier.

 

[RankRam]

That's where mine is, you can see it in my readers rig gallery.

 

[nickleinonen]

if i get some time and nice weather this sunday, i will be installing pyro/boost gauges [hopefully] . i think i will go pre turbo for the probe in this location... i hope i don't screw up

 

[XJSuperman]

Nick(and anyone else)... I recently did mine pre-turbo... I was literally shaking when I first drilled. But i had practiced on a spare piece of metal I had to be sure I could do it.



I went right off #3 cyl. straight up on the manifold. Very easy to drill and tap as there's nothing in the way(I had moved my air intake as I was installing a new one then as well). I greased the drill bit and tap liberally and just took my time. I then used a little "pencil" magnet to get the filings out. It;s been over 200 miles and I have yet to have any problems and man is the guage sensitive!!

Be scared... but do it. Once you start to drill there's no turning back and the fear will mostly go away.

 

[nickleinonen]

well i started my gauge install project today. all i got done was cutting up the dash and mounting the pyro gauge where the cig. lighter plug use to be. had to trim the back of the dash panel also to get room for the gauge [there was a spring clip mount point right behind the cig. lighter plug] if the weather holds good for the weekend, i will drill & tap the exhaust and intake horn for the pyro & boost fitting.



***edit***



picture of pyro gauge mounted in dash

 

[Rosco]

I have spoken to Scott at MassDiesel regarding drilling and tapping the manifold. He said that you really don't need to worry about the shavings from drilling and tapping. Just start up the truck and let it idle for a minute. He states that on startup the turbo is not spinning and all the chips immediately blow harmlessly out the exhaust.



I know this goes against what we anal TDR members (me included) have come to know but it does make sense. Also, Scott does these pyro's on a regular basis and I don't think he'd do something to jeopardize his hard earned reputation if it would bite him in the arse later.



Finally, I post this right well knowing most of you will still try to fish out as many chip's as possible. I just hope it calms you a bit when thinking about that one chip that got away .

 

[EEdmondson]

I thought I read somewhere that you drill with the engine running to blow the shavings out. Is this true?

 

[XJSuperman]

You can clog the tail pipe and then fire the motor and it;s supposed to blow the shavings back through the hole you drilled. I think the consensus is if you don;t have BIG chunks in there just use the magnet as best you can and then let the truck blow the rest out.

Genos told me this and Rosco in his post above was told the same by another manufacturer/distributor as well... and as said... they aren;t going to tell us to do something that will cause damage to our trucks.

 

[bpenrod]

I was worried when i did mine but greased the drill and tap to help catch the shavings and all was well. It wa still scary hitting the key the fisrt time! Nick, I'm curious why you would drill and tap the intake for the boost. Geno's sells a boost bolt pretty cheap that replaces one of your manifolrd bolts and your there. Piers also sells one at over double the price and the nice thing is if you ever remove the guage you can put the original bolt back in instead of plugging the hole you drilled. Just my 2 cents!

 

[JThiessen]

C'mon Guys! All you gotta do is obtain the correct drill speed and bit pressure to obtain a continuous curled chip!!! (I seem to do it often with Aluminum)

Good reminder about the boost bolt - gonna order one today, in addition to the triple guage pod.

 

[nickleinonen]

Originally posted by bpenrod

I was worried when i did mine but greased the drill and tap to help catch the shavings and all was well. It wa still scary hitting the key the fisrt time! Nick, I'm curious why you would drill and tap the intake for the boost. Geno's sells a boost bolt pretty cheap that replaces one of your manifolrd bolts and your there. Piers also sells one at over double the price and the nice thing is if you ever remove the guage you can put the original bolt back in instead of plugging the hole you drilled. Just my 2 cents!

i don't have one on hand, so i will drill & tap instead. geno's is a fine company to deal with, but i won't order from them again. i got burned good with duty charges first/last time. free trade my arse. i would buy one from piers, but i can get it all done tomorrow [if the weather is nice]. .

 

[Matt400]

I put it here: #ad




I had the opportunity to do two trucks and while I put them in the same spot I did them different...

The first one I unbolted the turbo and the front down pipe bracket on the bell housing.

Next I slipped in two strips of duct tape to cover/seal the turbo inlet and drilled away worry free then just used a little air to blow off the tape afterwords.



The next one I found that the turbo bolts were just too darn tight and I was afraid I would make even more work if I broke a stud so I drilled using a shop vac with the hose stuffed into a transmission funnel next to the bit.

I also greased up the drill tip, here is a pic:

#ad




Another idea is to attach an electric leaf blower to the exhaust pipe and seal off the intake system to pressurize the exhaust manifold. Wear safety glasses cuz any shavings once you penetrate through should blow back out.



I gave that some thought but imagine what would happen if by chance the seal you make on the intake comes loose and you blow not just the metal shavings but any other junk in the exhaust back into a cylinder that has a valve open

 

[swexlin]

I have spoken to Scott at MassDiesel regarding drilling and tapping the manifold. He said that you really don't need to worry about the shavings from drilling and tapping. Just start up the truck and let it idle for a minute. He states that on startup the turbo is not spinning and all the chips immediately blow harmlessly out the exha

Scott (Proram) of Renegade Diesel did mine like this today. Smooth as silk.

 

[DLeno]

I was just researching all this again and thought that an observation might be of interest to you guys. Concensus has it that approximately 1" up from the turbo flange, and toward the back of the e manifold is the hottest place. Well, I decided to do a reality check to see how valid this is:



With approximately 10,000 miles on my 04, the varnish is still mostly intact -- on the e manifold. Heat from running the truck has burned off the varnish in an interesting pattern: Unfortunately I can't get a good pic, but what I found was that the varnish burn-off pattern is centered just about where you guys say the hot spot is! each cylinder has the varnish still in tact, but it is clearly burned off where all cyls combine AND the center of this burn pattern is a tad off center towards the rear of the engine on the vertical portion of the manifold prior to entering the turbo.



just thought y'all would want to know that. I just can't help but wonder how this location was derived in the first place. Maybe someone was looking at varnish patterns

 

[JThiessen]

I'm just getting ready to drill mine, and thought I'd chime in here - the hot spot on my exhaust manifold is definitly right off the #3 cylinder prior to the the main collector. I wonder why we are seeing differing patterns here... ... .



My next question is do you ALL have 90 degree drill motors????? There's no way my cordless or my 1/2" will get in there..... gonna have to check out the air motors at work... .

 

[DLeno]

Interesting you raise this issue again. Having studied the varnish burn-off pattern I tried to get as close as possible to the "1 inch above the flange, rear of the partition" location which seemed to make the most sense. I didn't exactly acheive that location but thats not the purpose of this post



The reason I am posting here is because, now that my pryo is installed and I was able to get on the throttle a bit more, my manifold is showing signs of being heat treated . it is getting that bluish cast to it, signifying that the metal itslef has acheived 550-600 degrees F. My point is that the bluish areas do not correspond to the varnish burn-off areas. In fact, what looks to me to be the hottest place is this location: (!) look at the bluish pattern on the pic -- it looks a lot like mine.

 

[JThiessen]

Yep - mine is showing the hot spot right where the probe is in that pic (mistakenly identified by myself in the previous post as common to #3 Cylinder). Mine isnt blue (yet) - its a very dark rusty color there - much more so than any other spot on the manifold.

So, in the interest of this post, what we are after is the temp of the air heading to the turbo, so the collector is still going to be the best spot for this, even if one spot on the manifold is showing a hotter surface temperature. I think I'll put mine on the forward side of the collector. .

 

[DLeno]

other than the effect of the water jacket and proximity to that, why would surface temp not correlate with the temperature of the gas on the other side of the casting wall?



Also, the chief thing we are interested in is the temperature of the gasses exiting one or more cylinders -- in the interest of protecting them. Thus, if the air collected just before the turbo is a tad cooler, it would be best to measure upstream at the hottest cylinder exit point found on the manifold, no?



I can see that, unrelated to the aggregate EGT itself, there will be a temperature gradient of some behavior on the surface of the manifold, consisting of contributions from the water jacket (cool) heat soaking from the block (hot), surrounding air temp, and distance from the block. Are these the reasons you suggest that surface temperature does not correlate well with the EGT?

 

[Matt400]

Originally posted by DLeno

why would surface temp not correlate with the temperature of the gas on the other side of the casting wall?

I would say due to the heat shield. Most gas motors we see that have cracked exhaust manifolds are broke under the shield where the manifold can't dissipate heat as well.