4th Tubocharger on its way out

[ENafziger]

There is simply no way that a PacBrake can provide stronger exhaust retarding than a Jacobs EB unless it is somehow creating higher back pressure. There is no rocket science or mystery involved in an exhaust brake. An exhaust brake plugs the exhaust outlet creating back pressure.

That is true in a sense... however, people report better holding power with the PacBrake because it uses a variable size orifice to attempt to hold 60 psi over a broad rpm range.

With the Jacob's brake (which I have), the max braking pressure of 60 psi is only realized at high rpm... 3,000 and over. As the rpms come down, so does the backpressure, and thus the braking effectiveness. As such, by the time the engine slows down to 2,000 rpm or so, you may only have 35 psi of holdback pressure. This is due to a fixed hole in the butterfly.

The Pacbrake on the other hand, uses a variable orifice, to restrict the exhaust flow as rpm decreases, in an attempt to maintain the 60 psi across the rpm range. This is why the Pac offers much more holding power than the Jacobs, even though both are restricted to a 60 psi max.

I think the 60 psi setpoint on either system comes from an engineering design point concerning the factory valvespring rate. Any more pressure than this, and you risk valve/piston contact due to an exhaust valve not closing, due to not enough valve spring pressure.

I've wondered if it would be possible to run higher backpressure for those who have upgraded to F1 springs, hamiltons, pdr, etc?

--Eric

 

[ENafziger]

Concerning the failures being on manual trans vehicles only... could it have something to do with how "hard" the brake comes on?

I know in my truck with 3. 73 gears and 37" tires, I can leave 2 little black patches of rubber by downshifting aggressively into 4th gear and letting the clutch out fast... going around a corner, you can get a little sideways just from the braking action! :-laf

That begs the question... what is the turbo doing when "abruptly" engaging the exhaust brake? What exactly is the failure on the turbo? Is it the oil seals around the main shaft? Excessive play allowing oil bypass?

Can anyone with an automatic trans and exhaust brake get harsh enough engagement to break 37" tires loose on dry pavement?

Well, enough with my ramblings... just throwing out some thoughts.

--Eric

 

[RVTRKN]

Gentlemen, Bill from Pacbrake here, Harold has left Pacbrake as of May 12 2009. I'm sorry to be so late in providing what I believe is a key piece of information regarding these turbo failures. We know of 4 trucks experiencing this exact issue, the common thread is ALL are manual transmission equipped vehicles. I drive a 2004 1/2 with an AUTO trans which I ran a brake off one of these trucks experiencing this issue, it never exceeded 60PSI backpressure. I have 132,000Kms the original turbo with no problems, we even pulled the intercooler boots looking for any signs of oil, none found.

Mr Carlisle proved the issue is caused by something other then the brand of the exhaust brake.

Anyone have a theory on why the noted failures are all manual transmisison vehicles?

With no truck signature and with a little research, You have a standard trany I'm assuming. What about what Bill is saying about the manuals only failing, with the four he is aware of. I know its ridiculous because in 05, an auto is not setup for a EB and will void your warranty with an auto. But you have stated in the past that you pull at 26K GCVW, is your EB on extended periods when descending long grades pulling heavy. As I have mentioned prior, run the engine without the EB for 10K miles and see what happens. You can still pull that weight, and be safe. Just remember your fundamentals, always drop one gear lower than it took to go up the grade when descending and keep your speed at the Semi speed limits and start the decent 5 MPH slower than the limit braking back to the 5 MPH under when you reach the limit. I'm able to do this when I'm at the GCVWR of my 2500 with the NV5600, and there is no EB.

 

[HBarlow]

That is true in a sense... however, people report better holding power with the PacBrake because it uses a variable size orifice to attempt to hold 60 psi over a broad rpm range.

With the Jacob's brake (which I have), the max braking pressure of 60 psi is only realized at high rpm... 3,000 and over. As the rpms come down, so does the backpressure, and thus the braking effectiveness. As such, by the time the engine slows down to 2,000 rpm or so, you may only have 35 psi of holdback pressure. This is due to a fixed hole in the butterfly.

The Pacbrake on the other hand, uses a variable orifice, to restrict the exhaust flow as rpm decreases, in an attempt to maintain the 60 psi across the rpm range. This is why the Pac offers much more holding power than the Jacobs, even though both are restricted to a 60 psi max.

I think the 60 psi setpoint on either system comes from an engineering design point concerning the factory valvespring rate. Any more pressure than this, and you risk valve/piston contact due to an exhaust valve not closing, due to not enough valve spring pressure.

I've wondered if it would be possible to run higher backpressure for those who have upgraded to F1 springs, hamiltons, pdr, etc?

--Eric

That's an excellent explanation that makes sense. Based on the understanding I derived from your explanation it seems that we can assume that although neither brake can exceed 60 psi back pressure and, therefore, exhaust retarding force at high rpm would be the same between PacBrake and Jacobs, the average back pressure during a long deceleration slow-down from high speed/high rpm to near idle would be greater with the PacBrake than with the Jacobs which I am familiar with.

Perhaps it is the long period of 60 psi back pressure that is blowing out the turbo seals. The back pressure begins at or near 60 psi with a Jacobs EB but quickly declines as engine rpm drops.

You may have diagnosed the problem with the original poster's truck.

I suspect that if the dealer's service department had a clue they would void his warranty based on use of the PacBrake.

 

[BEmmert]

Good thoughts on the “long duration” of the 60 PSI with the PacBrake, however I can prove that theory wrong as can the original guy with the issue. I have a 98. 5 and have the older vacuum operated PacBrake with no variable orifice to keep it at 60 PSI and I to have had blown turbo seals on more than one occasion. The original guy I believed proved this as well once he went to the Jacobs brake as it works the same as my older PacBrake and he to still had issues.

 

[JCarlisle]

That's an excellent explanation that makes sense. Based on the understanding I derived from your explanation it seems that we can assume that although neither brake can exceed 60 psi back pressure and, therefore, exhaust retarding force at high rpm would be the same between PacBrake and Jacobs, the average back pressure during a long deceleration slow-down from high speed/high rpm to near idle would be greater with the PacBrake than with the Jacobs which I am familiar with.



Perhaps it is the long period of 60 psi back pressure that is blowing out the turbo seals. The back pressure begins at or near 60 psi with a Jacobs EB but quickly declines as engine rpm drops.



You may have diagnosed the problem with the original poster's truck.



I suspect that if the dealer's service department had a clue they would void his warranty based on use of the PacBrake.

I put on the Jake and the Turbo started leaking after 2000 miles. That is sooner than the PAC Brake and as for Braking the PAC is the Best Hands Down

The Service Manager and Dodge are over the Brake issue and are looking for other things now.

 

[JCarlisle]

With no truck signature and with a little research, You have a standard trany I'm assuming. What about what Bill is saying about the manuals only failing, with the four he is aware of. I know its ridiculous because in 05, an auto is not setup for a EB and will void your warranty with an auto. But you have stated in the past that you pull at 26K GCVW, is your EB on extended periods when descending long grades pulling heavy. As I have mentioned prior, run the engine without the EB for 10K miles and see what happens. You can still pull that weight, and be safe. Just remember your fundamentals, always drop one gear lower than it took to go up the grade when descending and keep your speed at the Semi speed limits and start the decent 5 MPH slower than the limit braking back to the 5 MPH under when you reach the limit. I'm able to do this when I'm at the GCVWR of my 2500 with the NV5600, and there is no EB.

I make a 200 mile run and I have one pull that lasts about 15 miles and climbs 3000 feet in elevation ( checked it with a GPS) the Pull starts out at 6% and turns to 8% for the last half. The majority of the Trip is up and down these kinds of Grades I put the exhaust Brake on after I had a scary ride with a Trailer that got a little squirlley at about 60 MPH and my Brakes were Hot From the Start. I started from the Top at 20MPH The Engine would not hold me Back. This would not have been a problem if not for the POS Trailer, at the bottom of the hill it is a straight away and you can usually let the Truck Gain speed without wrecking if towing a good Trailer.

I appreciate all of the tips and help that everyone has offered I just wanted to explain the Terrain a bit. I have been pulling these hills for 20 years and this Truck with the Brake is the Best Rig I have had in this time for the Job it does. It is also the first Truck that I haven't traded in before the Factory tires were worn out since 1999. It works Well and I like it.

I would like to get it fixed.

 

[HBarlow]

Thanks for correcting me. I guess I didn't read the part about the turbo failing again w/Jacobs brake. I remain clueless. I hope to learn what the cause is if the dealer ever figures it out.

 

[SSalzer]

I too have a Pacbrake w/manual transmission ('05) and am experiencing a turbo oil leak. I guess I make #5!

 

[brods]

JCarlisle, it sucks that they still can't get it figured out. If I were in your shoes I'd be contacting:



Cummins http://www.cummins.com/cmi/content.jsp?siteId=1&langId=1033&menuId=6&overviewId=33&menuIndex=0

Holeset www.cummins.com/turbos - USA (I'd start with the Marketing and Engineering support for North America at 812-377-9221)

and Jacobs: Jacobs Vehicle Systems - Contact Us



to see if their technical support departments have seen this type of recurrent turbo failure and what the likely cause is. I'd ask other questions too, like what the 60 psi back pressure limit is based on, is it the valve springs or the turbo seals or something else? What is the max safe back pressure for the turbo seals? What is the max safe egts for the turbo seals? Etc.



Hope you can get some answers and get your truck fixed for good.

 

[AH64ID]

That is true in a sense... however, people report better holding power with the PacBrake because it uses a variable size orifice to attempt to hold 60 psi over a broad rpm range.



With the Jacob's brake (which I have), the max braking pressure of 60 psi is only realized at high rpm... 3,000 and over. As the rpms come down, so does the backpressure, and thus the braking effectiveness. As such, by the time the engine slows down to 2,000 rpm or so, you may only have 35 psi of holdback pressure. This is due to a fixed hole in the butterfly.



The Pacbrake on the other hand, uses a variable orifice, to restrict the exhaust flow as rpm decreases, in an attempt to maintain the 60 psi across the rpm range. This is why the Pac offers much more holding power than the Jacobs, even though both are restricted to a 60 psi max.



I think the 60 psi setpoint on either system comes from an engineering design point concerning the factory valvespring rate. Any more pressure than this, and you risk valve/piston contact due to an exhaust valve not closing, due to not enough valve spring pressure.



I've wondered if it would be possible to run higher backpressure for those who have upgraded to F1 springs, hamiltons, pdr, etc?



--Eric

I just want to add a few observations based on my Jacobs EB and my DP gauge.



Max psi obtained is 63psi(verified on 2 gauges, his 63 and stops). 60psi is obtained from about 2500 rpm's up, lower if the EGT's are high from just coming up a large hill. From about 1800 rpms you have 50psi. 35 psi is obtained at 1100 rpms. From what I have noticed you really start to fell the braking at 45-50 psi.



Not that this is a Jacobs vs PB thread. . but I really don't want more braking at lower rpms, I like that lower rpms means more braking, more often than not my brake is off and on as it is. If I need more braking I downshift.







Yes the brake does come on hard with the manual trans, I will often blip the throttle on a downshift to get it to come off, so I am easier on the clutch. . . thou maybe the turbo likes it too?

 

[JCarlisle]

JCarlisle, it sucks that they still can't get it figured out. If I were in your shoes I'd be contacting:



Cummins http://www.cummins.com/cmi/content.jsp?siteId=1&langId=1033&menuId=6&overviewId=33&menuIndex=0

Holeset www.cummins.com/turbos - USA (I'd start with the Marketing and Engineering support for North America at 812-377-9221)

and Jacobs: Jacobs Vehicle Systems - Contact Us



to see if their technical support departments have seen this type of recurrent turbo failure and what the likely cause is. I'd ask other questions too, like what the 60 psi back pressure limit is based on, is it the valve springs or the turbo seals or something else? What is the max safe back pressure for the turbo seals? What is the max safe egts for the turbo seals? Etc.



Hope you can get some answers and get your truck fixed for good.

Thanks for the Tip I will start emailing and calling Monday

 

[Grizzly]

I still want to know if the problem is due to the PacBrake because I still want to install one in my truck. Of course I don't want it if it's going to create that much of a problem.

 

[brods]

I just want to add a few observations based on my Jacobs EB and my DP gauge.



Max psi obtained is 63psi(verified on 2 gauges, his 63 and stops). 60psi is obtained from about 2500 rpm's up, lower if the EGT's are high from just coming up a large hill. From about 1800 rpms you have 50psi. 35 psi is obtained at 1100 rpms. From what I have noticed you really start to fell the braking at 45-50 psi.



Not that this is a Jacobs vs PB thread. . but I really don't want more braking at lower rpms, I like that lower rpms means more braking, more often than not my brake is off and on as it is. If I need more braking I downshift.







Yes the brake does come on hard with the manual trans, I will often blip the throttle on a downshift to get it to come off, so I am easier on the clutch. . . thou maybe the turbo likes it too?

That brings up a few questions. Are EB’s designed to close slowly to avoid high pressure spikes? On a downshift where the brake is left engaged, is there a high pressure spike as the EB is initially responding to the rapidly increased pressure? Is this worse with a manual trans? Can this spike be causing excessive blowby past the turbine seals causing elevated crankcase pressures or just elevated pressures in the bearing area of the turbo which then causes leakage past the compressor seals? Can this short duration event cause relatively little damage, but when repeated over and over again it eventually lead to seal failure?





For those that are interested, here is Holset’s site to learn more about turbo failures: www.cummins.com/turbos - failure diagnosis

Here is their Turbo Trouble Shooting pdf from their literature section: http://www.holset.co.uk/partsservice/service/TurboTroubleShooting.pdf

Remember, if the root cause of the problem is not identified and corrected your problem will remain!

 

[Southbound]

TDR Brethren-

I currently have a PAC Brake installed on my 06 manual transmission however I have never completed the install as I have been doing research on how I want to run the on-board air. After reading this thread I am reluctant to proceed any further until I see what the outcome is.

Southbound

 

[JHardwick]

Turbo failures on unmolested Cummins engines are not common. I put lots of miles on an '01 and an '06 and have never had a turbo problem. Have known lots of RV transporters and a couple of oilfield hotshotters who put hundreds of thousands of miles on Dodge Rams and have never replaced a turbo.

I just hit 500,000 on my stock charger.

 

[Grizzly]

Jim Gail, jelag, of Pacific Clutch & Brake asked me to cut and paste his thoughts on the topic situation concerning PacBrake as emailed to me from him;





I haven't been on the TDR for a while (months)...

let me assure you that the exhaust brake, no matter

if it's a PacBrake, Jacobs, Banks, or any other brand

can not do damage to the turbo... .



If this were the case, than these devices wouldn't be

approved by most engine manufacturers... . remember

that the PacBrake doesn't work much differently than

the others... . except the ability to hold the back

pressure for a longer period of time... .



Also remember that PacBrake sets the back pressure

based on suggested numbers provided by the engine

manufacturer and extensive dyno testing...



I'll get to the TDR again but I guess it will be a

week or so... . We've just had a lot of personal

stuff going on and I've had to cut back... . but

your more than welcome to cut and paste this into the

thread if you wish...



What you really have is some under lying problem and

the customer has now taken the stance that since he

or the shop repairing this truck can't find the real

problem they are blaming the exhaust brake, as its

hung on the turbo...



I personally have owned 10 trucks in the past 15

years, have put 500K on each before the sale of that

truck, selling all of them with the factory turbo and

exhaust brake that we installed in the first 500

miles of the engines life. .



Hope this helps...



Jim



Pacific Clutch & Brake

1124 N Freya St.

Spokane WA 99202





Additional comments from jelag;



There is no problem with

using an exhaust brake or engine brake on any engine

that is designed for their use... . and the engine

brake or exhaust brake will cause NO problems or

damage to the engine...



When the 5. 9 first started to get exhaust brakes was

in the light trucks that the engine was put into... .

not pickups... than pacbrake designed the direct

mount and got approval from Cummins to offer it in

light trucks... later the design was introduced for

the pickups where the 5. 9 was installed by dodge...



There were also some F650, and F750 early on where

you could order Cummins and mount the same pacbrake...



Each pacbrake was designed based on if the engine had

vacuum or air... . based on the early production... .



Jim

 

[JCarlisle]

I traded the Truck in on a 2009 got a good deal. I pulled the Brake and other accessories and will be putting both brakes on Craigslist. I really like the way the new 6. 7 exhaust brake works and the new Auto Trans works great

Thanks for all the advice

 

[MMeier]

I traded the Truck in on a 2009 got a good deal. I pulled the Brake and other accessories and will be putting both brakes on Craigslist. I really like the way the new 6. 7 exhaust brake works and the new Auto Trans works great

Thanks for all the advice

So, where are the pics of the new ride, details, price, where bought, etc. ?

 

[jelag]

JCarlisle.....

I'm a little late getting to this... I mentioned in another thread that I have access to a group of rebuilders who know how to look for cause of failure in the products they rebuild... just as we do in Clutches, Air Compressors, Fan clutches etc... .

I assume that real failure analysis is not done on Dodge warranty parts... as I understand that Dodge buys the complete turn key package from Cummins and assumes all warranty issues... so the real guys who know (Cummins) never really ever see's the parts...

I personally have owned at least 10 trucks in the past 15 years. . All Fords & Dodges with an even spread... . I sell my trucks with 500K miles, have never replaced a turbo and all have run PacBrake from day one and we changed to the PXRB through a program provided by Bill at PacBrake during the roll out of this new product... .

I'm willing to do the research and send a turbo to an independent rebuilder for analysis if someone has a failed one they wish to send me... .

But you need to consider this... as mentioned in all these pages... .

1 - all brakes work the same using back pressure and usually controls from the ECM...
2 - all brakes can use the fast idle warm up if the ECM on the truck is programed to turn on the brake... after at least who knows how many installations we've learned that all trucks of the same year with the same transmission are not programed alike... . at least in the way the ECM works... its like there is at least 5 different software versions... .
3 - Cummins, CAT, and several other engine manufactures offer engine brakes and exhaust brake options at the factory with an engine purchase... . and they used to offer your choice of a PacBrake or Jacobs... . remember this is not a pickup option but sometimes the same engine used in a mid range truck... .
4 - PacBrake in their wisdom not to share some of the stuff they do... . could tell you they sell and service a lot of exhaust brakes on military vehicles that have the common CAT, Cummins, and other engines we are seeing around our world... even though our leaders (Congress - Whitehouse) make some foolish mistakes, most of the military stuff is done with sound engineering...
5 - I can share with you... . that we rebuild air compressors and 80% of the returning cores have nothing wrong with them... we're not talking warranty stuff, just the raw core where the air compressor was replaced, for some reason, but driving that air compressor on our dyno for 3-4 hours finds nothing wrong with it... . this alone is a very hard nut to swallow because I believe that 80% of the compressors replaced at a $1,000 a pop with labor are done for lack of ability to correctly understand how to test and diagnose problems and repair said truck... using this a rough guide you'll see why I'm on record with my post in another thread by JCarlisle... . that there is another problem that is being overlooked and that is the root cause of the failures... it just hasn't been found... .
6 - we belong to an association, APRA, Automotive Parts Rebuilders Association, I happen to be the chair of the Clutch Division but we have several HD rebuilders, like us... that do Turbos... . they would be the ones that I'd focus on... . We're a world wide group, that includes engine builders, transmission builders, Jasper Engine and Transmission is a member... South Bend Clutch used to be a member but I don't know if Peter still belonges... . I don't have that information... . anyway this group might have the best wealth of knowledge in our industry... we just need to tap it. .

I'm going to stop here as there might be a limit to posting and I don't want to retype this... .