Is the 6.7L Turbo Water Cooled

[TMRoper1669]

I have heard several things regarding the turbo on a 6. 7L being water cooled, I looked and can seem to make heads or tails of it. Is this True and if so this would allow the turbo to run hotter, Correct?

 

[JDiepstra]

You have heard several things that are incorrect.

 

[pcarlson]

It is water cooled.

 

[TMRoper1669]

You have heard several things that are incorrect.

Thanks, for the reply

 

[Bob4x4]

6. 7L DIESEL





6. 7L TURBOCHARGER

1 - TURBINE

2 - TURBOCHARGER SPEED SENSOR

3 - COMPRESSED AIR FLOW

4 - COMPRESSOR

5 - FRESH AIR FLOW

6 - YOKE MECHANISM

7 - NOZZLE RING

8 - SHROUD PLATE

9 - AIR FLOW TO ENGINE

10 - VANES



The electronically controlled Variable Geometry (VG) turbocharger is a water cooled, exhaust-driven, oil lubricated compressor that increases the pressure and density of the air entering the engine. With the increase of air entering the engine, more fuel can be injected into the cylinders, which creates more power during combustion.



The VG turbocharger allows the engine to operate in a wide power and speed range to achieve the best power, torque, and engine operating conditions.



The VG turbocharger can also provide engine braking and to reduce engine warm up time.



The VG turbocharger assembly consists of:



Turbocharger assembly

Variable Geometry Nozzle (7)

Water Cooled Bearing housing

Electronically Controlled Actuator

 

[HBarlow]

6. 7L DIESEL


6. 7L TURBOCHARGER
1 - TURBINE
2 - TURBOCHARGER SPEED SENSOR
3 - COMPRESSED AIR FLOW
4 - COMPRESSOR
5 - FRESH AIR FLOW
6 - YOKE MECHANISM
7 - NOZZLE RING
8 - SHROUD PLATE
9 - AIR FLOW TO ENGINE
10 - VANES

The electronically controlled Variable Geometry (VG) turbocharger is a water cooled, exhaust-driven, oil lubricated compressor that increases the pressure and density of the air entering the engine. With the increase of air entering the engine, more fuel can be injected into the cylinders, which creates more power during combustion.

The VG turbocharger allows the engine to operate in a wide power and speed range to achieve the best power, torque, and engine operating conditions.

The VG turbocharger can also provide engine braking and to reduce engine warm up time.

The VG turbocharger assembly consists of:

Turbocharger assembly
Variable Geometry Nozzle (7)
Water Cooled Bearing housing
Electronically Controlled Actuator

Good answer.

Maybe you have an answer to this question:

Does the use of a water cooled turbo in the 6. 7 engine change the guidelines regarding exhaust gas temperature for engine shut down?

With my first Dodge-Cummins, a 2001 HO 6 speed, I learned from TDR to idle the engine and wait until EGT cooled to 300* before shutting down to avoid coking the oil in the turbo bearing(s). At the summer 2002 TDR Rally @ the MREP in Columbus, IN a Cummins engineer told me that allowing EGT to cool to only 350* was adequate for safe shutdown.

I have gauges on my C&C with Cummins 6. 7 engine. The EGT seems to cool slower with the 6. 7 engine than on previous 5. 9 engines and extremely slow if it happens to be in the regeneration mode when I am ready to shut it down.

Does use of a water-cooled turbo mean it is safe to shut down while the EGT is still high?

I've submitted this question to Robert Patton to add to his list of questions to ask Cummins, Inc. about the new 6. 7 liter engines but it will take a while for him to obtain the answer then publish it in TDR magazine.

 

[Jim W]

I believe in the owners manual not sure of the page number (I do not have it with me now, it is in the truck). The manual states a time period for letting the turbo to cool down after running the engine under various conditions. One of these conditions was towing, the manual stated a time period to wait before shutting off the engine. After I installed my gauges I timed this period when towing and watch the EGT temps as I idle to cool down. The gauge read about 400F when I reached the time period that Dodge recommend for shut down. This has been my guide line since then for shutting down the engine on my truck under all conditions.

Watch some 5. 9L reader chime in and say I am trashing the turbo. They seam to know more about these engines then the engineers who design these engines.

 

[HBarlow]

I believe in the owners manual not sure of the page number (I do not have it with me now, it is in the truck). The manual states a time period for letting the turbo to cool down after running the engine under various conditions. One of these conditions was towing, the manual stated a time period to wait before shutting off the engine. After I installed my gauges I timed this period when towing and watch the EGT temps as I idle to cool down. The gauge read about 400F when I reached the time period that Dodge recommend for shut down. This has been my guide line since then for shutting down the engine on my truck under all conditions.
Watch some 5. 9L reader chime in and say I am trashing the turbo. They seam to know more about these engines then the engineers who design these engines.

Thats a great idea! I never thought of watching the EGT on my pyro gauge to determine EGT at each minute interval corresponding to the owner's manual shutdown guidance. DUHHHH!

Now that you pointed out such a simple, practical, and logical technique for determining shutdown temps I have noticed that cool down to 400* doesn't take long but waiting until EGT cools to 350* tries my patience.

You're correct. My owners manual for the C&C also contains the shut down delay guidance suggesting the driver wait between 1 minute (routine city driving with light load) to five minutes (full power, heavy highway towing).

 

[HBarlow]

Well, I answered my own question.

I've been wondering for a year since I bought my '08 C&C about shutdown temps. This thread got me thinking about the question again today so I finally took the initiative to call Cummins, Inc. and ask. It took a while but I finally worked my way through the computer call screener and the customer service rep who provided a generic answer and finally spoke to someone I knew who referred me to someone who could answer the question.

Here's the answer from Cummins:

Hot shutdowns at egt up to 600* are not likely to cause harm.

The turbocharger used on the ISB6. 7 has a higher heat tolerance than previous generation turbos because of the more restrictive emissions requirements on the 6. 7 and the need for regeneration of the emissions components.

Also, because the ISB6. 7 engine turbo is watercooled, it can tolerate hot shutdowns better. Our old TDR guidelines of allowing egt to decay to a maximum temp of 350* is no longer applicable.

The Cummins rep I spoke with today told me that a short cool down delay is desirable following full load, full power operation such as heavy towing at highway speeds but he said it is not harmful to shut down with egt as high as 600* which it can be if the engine is in the regen mode immediately before shifting to Park position.

I think Robert Patton wrote a similar opinion in a previous issue of TDR magazine where, IIRC, he stated that he routinely drives his Ram pickup w/ISB6. 7 engine like a gas engine. I think Robert said he uses no idle delay for cool down at all.

I think I'll start a new thread with this same information so that more ISB6. 7 owners and prospective owners will see the answer.

I have never before in my life found a major American corporation like Cummins, Inc. whose staff will freely take calls from customers, ordinary individuals like me who owns only one little Cummins-powered Dodge Ram, not a fleet of trucks. Not only will they take calls from customers but they always provide thoughtful and complete technical answers to product questions. Every time I have had a reason to call or e-mail Cummins and the privilege of speaking to a professional employee of Cummins, Inc. my appreciation for that great old American company grows. Thank you to the professionals who spoke with me, and thank you Cummins, Inc. I wish Cummins, Inc. every success and each and every Cummins employee a long and successful career.

 

[Bob4x4]

The water cooling was needed to keep the vgt stepper motor alive,the less critical shut down was a nice benefit

 

[Bill Stockard]

I have never before in my life found a major American corporation like Cummins, Inc. whose staff will freely take calls from customers, ordinary individuals like me who owns only one little Cummins-powered Dodge Ram, not a fleet of trucks. Not only will they take calls from customers but they always provide thoughtful and complete technical answers to product questions.

In the nearly 30 years I worked in the heavy truck business, Cummins was like you stated. It's one of the reasons why I strongly recommended my customers consider Cummins engines in their new truck purchases. I changed several of my customers from Detroit Diesel and CAT over to Cummins. They became loyal Cummins users and thanked me for it later.



Bill

 

[TMRoper1669]

After reading the owners manual the shut down time seems to be alot shorter then I remember it being in my '93,'99 and my '04. 5. It sure makes in nice,although I will really appericate it once gauges are installed. Thanks for all the info.

 

[gsbrockman]

Very useful thread... ... . I've been watching my EGT's through my EDGE Insight and generally have waited until 350*F or so... ... probably has been a little overkill in hindsight.



I may just shut it off at 375*F to 400*F then... ... ... :-laf



Greg

 

[grasmo]

At what temp. does your brand of oil boil off at???That is the $64 Question.

 

[HBarlow]

At what temp. does your brand of oil boil off at???That is the $64 Question.

Not really that important. EGT on the 2001 Dodge Ram w/ 275hp injectors I previously owned ran as high as 1500-1600* for brief periods under full power, full load and without a water-cooled turbo and regular old Shell Rotella handled that heat. As long as I allowed a cooldown to 350* or below before shutdown I never experienced a problem.

Cummins engineers designed and built the ISB6. 7 so that water cooling will protect the turbo bearing(s) from oil coking. The coolant temp is not going to be higher than around 200* and is taking heat out of the turbo housing just prior to and after shutdown.

 

[Bob4x4]

The oil in the CTD flows at a good rate. Engine oil carries heat away from bearings and thanks to the oil cooler keeps coming back for more even under extreme conditions. Once the flow stops is when the turbo has a chance at testing the oil.

 

[JDiepstra]

HOLY SMOKES I just wanted to come back and kick myself in the pants for being wrong and say thanks for correcting me guys!



I was thinking the OP meant plain water but now understand he was talking about coolant. Frickin' 5. 9 guys I tell ya... .

 

[grasmo]

Exactly, when the oil pressure goes to zero what temp is the shaft? And wouldn't the oil that is laying on the shaft possibly coke?

 

[HBarlow]

Exactly, when the oil pressure goes to zero what temp is the shaft? And wouldn't the oil that is laying on the shaft possibly coke?

It might if the turbo was not water-cooled. The coolant acts as a heatsink absorbing heat and preventing coking of engine lube oil in the turbo.