I just insatlled a Jacobs E Brake on my 97 3500, and i am not sure it is working to its potiential, I tow an 8000# trailer and in 4th or 5th gear down a grade it wont hold or slow the truck, I still get some acceleration. My other question is where does all the exhaust escape from? When I activate the brake it makes a relativeley loud hissing noise -- is this the wat it should sound and act? I bought this from a friend who never used it, so I have no idea of what to expect out of this thing.

 

Since you have a 12 valve, did you upgrade to heavier exhaust valve springs?

The 24 valve engines already have the heavier exhaust valve springs from the factory, the 12 valve engines did not, and need the heavier springs in order for the E-brake to work.

In addition to the hissing sound, it should rap just like the big boys do.

 

I am not sure I understand why I would need heavier exhaust springs for an exhaust brake -- doesnt it work simply by creating back pressure? As far as the rap sound, I thought that was only created by an actual Jake (engine) brake?? Like I said I am new to this exhaust brake so any info I gather here is all new to me. what is the price of the exhaust springs, and is the install pretty straight forward? Thanks for the help

 

If you don't use the the 60 lb exhaust valve springs on the 12v, the tremendous back pressure that the e-brake creates will literally blow the exhaust valves open and you will lose a lot of your retarding power. My experience with my Pacbrake is that you don't have a lot of retarding power under 2000 rpm either. When towing heavy, you may have to drop down to 4th gear slow the truck on a grade at highway speeds to get the desired retarding power.

Swapping valve springs isn't a big deal.......they are quite inexspensive and most shops should be able to do this for you in a couple of hours if you can't change them yourself.

And yes, the hissing sound is normal but it will thump fairly loud under load at 2500 rpm!!

 

Hello
I have a exhaust brake on my 2001 with the 6 speed. When you turn it on there is a rather loud HISS out of the tail pipe. There is a flap that closes and all of the exhaust is forced out of a hole in the flap, the hole is about the size of my index finger.
You will not get the big rig JAKE BRAKE sound. The JAKE BRAKE on the big rigs shut off the fuel and turn the engine into a air compressor in a sense. That is where the sound comes from.

The exhaust brake I have ( which I think is the same one you have) will slow you down. I have moved a goose neck trailer a few times loaded 18,000 lbs truck trailer and a farm tractor and on another trip ( or ten) a fith wheel camper. Coming down the West Va turnpike 5 % grades and maybe more, I would leave the truck in 6th gear and use the exhaust brake, I would lose speed and have to turn it off.

As suggested in the above replies you may want to get the stronger springs to make your exhaust brake work.
Hope this helped
See Ya
Chris

 

Sorry to hijack the thread, but im wondering if an e-break is 'hard' for the turbo. The back pressure it creates on the turbine side, it not hard on the turbo shaft ?

Cheers,
Marc/

 

The back pressure blows right by the turbine.......no ill effects.......you can hear a loud huff if you were boosting very high and then suddenly let off with the brake engaged.......that is not good because you get some pressure reversion on the compressor side - that is hard on main shafts because the compressor wheel is trying to stall.......but this happens even without a E brake though, it can precipitate the effect if misused. Other than that, the E brake is not hard on a turbo at all.

 

You will get a BIG RIG sound if....

1. Remove the air snorkel going into the fender or go to a BHAF or Scotty ][.

2. Remove your muffler and resinator and put in a striaght pipe.

3. Remove the silencer ring in turbo.

If you stock setup your going to get a light hissing noise...

With the above mine rattles to a stop like the bigger cousins...

 

I had no idea you could get them to sound like that.... I allways thought it was just a hissing sound....... NOW I WANT ONE !!!!




KP

 

Most of the rattling sound comes from the air box under the hood...

But all the mention mods really do help in making it sound like a real rig and not a toy...

 

Who has the best deals on Jacobs Brakes?
Topper

 

I got mine at a DC Dealer for about $800...

Shop around there out there for a good price...

 

Hi -- Thanks for all the input -- I put an ad on the local radio program "Trades & Sales" -- A friend called me and said a mutual friend had one on his truck that was unused -- anyway got it for $300.00 -- After reading the replies, bought a set of heavy valve springs today, hope toget them in tomorrow -- again, thanks for all the replies.....

 

Yu folks really lost me with your explaination of the brake. If you think about it, if there is too much "backpressure" on the exhaust valves, you say it will blow the valve open. That means it is supposed to be closed. When it closes, where is the piston when all this is going on? I wonder. You will have a lot more trouble than "the brake not working like it's supposed to", with the exhaust valve open, when Cummins designed it to be cosed at that time in the cycle.

Some folks can really cause trouble when they explain a cure to a problem they really don't understand..

..Be careful..

.Preston..

 

Preston,

You don't blow them all the way open!!! You crack them open slightly......enough that they lose their seal and float.........but not enough that they smack the pistons. It is perfectly possible on a CTD to have some valve float and not have the valves contact the pistons......why else do you think the heavier exhaust valve springs are required on a 12v when an E brake is installed?

Nobody else appeared to have a problem with this explanation or voiced a concern about some "trouble" with the explanation. Instead of saying "Some folks can really cause trouble when they explain a cure to a problem they really don't understand", why wouldn't you just politely ask that the explanation be clarifeid to clear up any misunderstanding that you may have instead of accusing someone of not knowing what they are talking about? These forums on DTR are very friendly with the way everyone shares their knowledge and experience......let's keep it that way.