Best pyro drill location?

[Agades]

just talked to Rod today and asked him about the probe location



he said to use the same dimensions as the 2nd gen (turbo tims diagram)

and make sure to use the rear port because cylinder 6 is the hottest running cylinder (rear port includes 6)



a short bit and an air drill or 90 deg attachment is necessary because of the tight area

 

[KatDiesel]

Heres a post by another user that just moved his probe from POST turbo to PRE turbo... ... ... ... .....



Add 300 degree myth

 

[Hohn]

That was me, Kat. The earlier post about the stock vs. modified truck was to me most interesting. I second all the mention of pyro as control mechanism vs. diagnostic tool.



Charlan, a class 8 rig is much different. First, they are almost always stock. You won't see a big truck "drive by the pyro" because they simply aren't that heavily fueled to where they could hurt the engine. Thus, the post pyro location offers both diagnostic capability and low cost. Think, too, about cracked manifold and other things that the class 8 guys would rather not mess with. Moreover, the TOT that a post-location measures are there more to monitor the turbo temp, not EGT.



A pyro is a live or die thing for a BOMBED ctd. So you can't go by cost. You simply need more accuracy. Measuring the one hottest cylinder (or 3 hottest cylinders) EGT will give you a good, worst-case picture of what's going on in the engine as a whole. True, it won't tell you WHICH cylinder is having problems if you notice something, but neither will the post-turbo location. One thermocouple per cylinder is the only way to accomplish the ideal.



I moved to Pre-turbo and I am glad I did (as my post says so). I should have done it that way to begin with, but I was afraid of tapping my manifold.



Justin

 

[skobylenski]

I didn't really feel like reading 3 pages of people kicking charlan's ass, so I'm just going to put in my response, and I appologize if someone already threw this out there. I think the reason Class 8 trucks have the pyro drilled post turbo is simly because there is not much room on the manifold, so they do it pruely for convenience. That's what I've noticed working for a local trucking company, anyway. All three major manufacturers (Cummins, Cat, Detriot) are the same - post turbo, and all three have little space on the manifold. Anyway, that's just my $. 02 on this matter.



How's the asbestos underwear holding up?

 

[DMC]

Post turbo will definately prevent a probe from falling off and going into the turbo on our engines. The Emd 12645 F7B's we run on the tug boat have probes on each exhaust manifold. But EMD puts parts screens on the front side of the turbo to prevent it from being destroyed by flying parts in the event of a piston or ring failure. I understand that the class 8 trucks all have the probe post turbo but have never seen temps over 900 anywhere in the US. Most all of the class 8 trucks are set up to run in a safe temperature zone. You dont screw around with a 25-30 thousand dollar engine unless you really know what your are doing with its longivity. There are a few shops around that modify road truck power plants. But the reputable ones know how to set them up without grenading them. Of course it is also up to the driver to do his part and not pull a hill in to low of a gear and hold it there. That is when I have seen the highest temps when pulling the rpms down to low and not downshifting.



I will probably put the probe on my engine pre turbo but wouldn't mind having one post so I can accurately monitor shutdown temps.



Good Luck



Be nice



Don

 

[dpuckett]

I sold a Ram CTD to a guy who rebuilds Cumins and Detroit diesels. He is one of a few mechanics in this county who will even touch a diesel. Since he has been working on them for 20-odd years, he invariably knows more about them than any 22 year old ever could. He mentioned the part abouth the tip breaking off (I had the t-couple mounted pre turbo) and trashing the turbo, and most likely the engine with it. I have since read here and on other truck related sites that that is an urban legend, and if the tip breaks, you have BIG problems. Anyway, that, along with his comment about any AFC adjustments having no efect on the fuelling/ performance of a VE pump, killed any confidence I might have had in his ability as a B series machanic. Aparently, this urban myth is still floating around, due to longevity of careers of mechanics and others "who know their stuff. ", as opposed to research and development, and real world experiences. I noticed in my early 91, that I NEVER EVER hit 900 deg the week I had the pyro mounted post turbo; had a machine shop drill and tap the manifold, and I could EASILY hit 1350 up a 5% grade empty. At 20 psi at the high temp, there goes the 10 deg per psi boost.



disclaimer- I am by NO MEANS an expert in this field, and meant no offense to anyone on this board. For towing, I have read about and talked to several shops recommending PRE turbo mounting, to monitor overheating up a hill. I am my own warranty station.



Daniel