PACBRAKE JakeBrake on a PPump 24v

Jacob 76

Jacob 76

Let'er Buck
Joined
May 3, 2011
Messages
365
Could one of these be adapted to fit on a mechanical engine? I know it will bolt on but would there be any way to control it? They dont give much info about it on the website, about the only thing they give you is this picture.

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It makes sense how it works I just dont know how you would time it with your valve train or control it?
 
rig it to a manual switch, and you could put that switch on the gear shifter (if its a standard). Seems cut and dry unless i missed something? Ive drove big trucks like this but, it wont have the low rpm cut-out.$.02
 
The part you are looking at is available for the 24v head. It is not a "jakebrake" in the sense of a compression brake. It is designed to work in conjunction with an exhaust brake or vgt charger, not as a standalone brake.
 
I dunno, the flyer I got from pacbrake calls it an integrated engine brake for the 6.7 Cummins. The picture with it sure looks like a Jake head.

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I understand it to work like this. When you're off the fuel coasting down a hill there is no need for a compression event to happen, therefore this unit opens all the exhaust valves on every stroke. This in turn makes the engine pump a higher volume of air which creates higher back pressure in the manifold and more effective braking. This unit must be used in conjunction with an exhaust brake because as a stand alone unit it will most likely reduce engine drag @ 0% throttle input.

For those of you who have a hard time wrapping your mind around the concept that this is not a stand alone compression brake, you need to study a "Jake Brake" until you understand exactly how one works, only then will you understand how this works.
 
If all you need is a switch to activate it, what's to keep it from holding the exhaust valves open too long or at the wrong time and they smack a piston?
 
Here, I did the web search for ya! ;)

Pacbrake P67 LoadLeash Engine Brake
By Scott Dalgleish

While I was up having the PRXB and air bags installed in my 1998 Turbo Diesel this past winter, I was treated to a look and test ride of the all new P67 engine brake for the Cummins 6.7.

How does it work? Unlike an exhaust brake which is the typical “potato up the tail pipe” device, the P67 engine brake holds an exhaust valve open to take advantage of the engine’s compression stroke to build retarding pressure as opposed to just using the exhaust stroke. The results are amazing!

The brake is a system of electronic and hydraulic components housed in an aluminum body, which replaces the “spacer” on the top of the head, below the valve cover. Within the new spacer a solenoid actuates a valve that uses oil pressure to hold the exhaust valve open, thereby taking advantage of the engine’s compression stroke.

The brake is controlled via a programmed module that automatically engages and disengages under varying conditions, making the use of the brake as simple as turning on a switch. The test vehicle I rode in had a 20,000 lb. load and was equipped with the cab and chassis version automatic transmission. We descended six and seven percent grades using service brakes, the VGT exhaust brake, both the P67 and VGT brakes and just the P67 engine brake. In a word, the brake’s performance is impressive!

During our test-drive we descended grades that required hard service brake application. Then we repeated the same descent using the VGT brake and service brakes…better, but still required a significant use of brake pressure to control the service truck’s speed. Next we used both VGT and the P67, and not only did we not need to apply the service brakes, our speed actually SLOWED during the descent.

The sound of the P67 meets the global requirements for noise, but has a definite big rig tonal quality, the kind Turbo Diesel owners will love. Will every Turbo Diesel owner NEED one? If you are using your Turbo Diesel to haul heavy, then I would put it on my list of GOTTAHAVITTS… but then you be the judge.
Click to expand...

Or you can read it here.
 
"The brake is controlled via a programmed module that automatically engages and disengages under varying conditions, making the use of the brake as simple as turning on a switch. The test vehicle I rode in had a 20,000 lb. load and was equipped with the cab and chassis version automatic transmission. We descended six and seven percent grades using service brakes, the VGT exhaust brake, both the P67 and VGT brakes and just the P67 engine brake. In a word, the brake’s performance is impressive!"


Only problem is they didn't say how just the Jake worked. If this thing had any real braking power on its own I bet they could sell a good amount of them to guys with aftermarket turbos.
 
LReiff said:
I understand it to work like this. When you're off the fuel coasting down a hill there is no need for a compression event to happen, therefore this unit opens all the exhaust valves on every stroke. This in turn makes the engine pump a higher volume of air which creates higher back pressure in the manifold and more effective braking. This unit must be used in conjunction with an exhaust brake because as a stand alone unit it will most likely reduce engine drag @ 0% throttle input.

For those of you who have a hard time wrapping your mind around the concept that this is not a stand alone compression brake, you need to study a "Jake Brake" until you understand exactly how one works, only then will you understand how this works.
Click to expand...

Not exactly, it does compress the air but the exhaust valve is then hung open to release the stored energy in the cylinder (the compressed air) out the exhaust not allowing the compressed air to push the piston back down. Look at a P-V diagram for a engine.

You also do no need a VGT for a compression brake to work. Either can work independent of each other.

Tobin
 
Its a legit Jake! I always wondered why nobody had attempted to build one for a b series.

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Well then, if you're all convinced it's the real deal, buy one and let me know how it works as a stand alone brake! The info I got from the package brake rep.could be wrong.
 
The way they describe it is just how a Jake works, I'm sure it'll work better with the vanes closed on a vgt, but I don't see why it wouldn't work better than a regular exhaust brake on a standard turbo.

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We will be testing these at the end of the month..they work like all real jakes... Oil psi holds down a electric over hydraulic servo that holds the exhaust valve open . Retail is in the 1800 range with install between 4 to 6 hrs....
 
I retract my previous statment. I assumed the OP was speaking of a standard exhaust brake.
 
I understand how they work like a compression brake in the respect of hydraulic solenoids holding the valves open. The part that I don't understand is how the thing is timed to open the valves for maximum effort braking when there is no mechanical component to do such as there is on a Jake.brake found on a big rig motor. I drove and worked on big trucks for years and played with the parts in the Jake brakes to make them perform better and have more braking power. This unit lacks all those parts that make it possible to time valve opening and function as full fledged Jake brake.
 
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Its probably set up the same way as a mechanical cat Jake.

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Mechanical Cat jake, like all other jake found on big rig motors are actuated by one of the rockers.
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Yeah, I see what you mean. It doesn't say that it won't use an exhaust rocker but its not real clear on what it will use. Maybe it just piggybacks the injector solenoid signal and fires completely electronically? Kind of like an electronic version of the mechanical Cummins Jake.

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chevota84 said:
Yeah, I see what you mean. It doesn't say that it won't use an exhaust rocker but its not real clear on what it will use. Maybe it just piggybacks the injector solenoid signal and fires completely electronically? Kind of like an electronic version of the mechanical Cummins Jake.

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Not possible. There is one solenoid to activate all 6 cylinders, making it either on or off.
I have talked to people and studied this thing thoroughly to come to my conclusions. If someone puts one on their truck and shows me that it works as a standalone brake then I'll believe it.
 
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Looking at in on a bigger screen, it sure seems like it is just holding the exhaust valve open for the whole time. If that's the case, I doubt if it'd work well without the vgt providing back pressure.

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