Jake Brake?
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Tuned
Joined: Aug 2006
Posts: 327
Likes: 79
From: Runnells, Iowa
Jake Brake?
Anyone here put one one an N14 that didn't come with on from the factory? I can buy the jake at the junkyard for $750. Any info appreciated. Casey
Last edited by Diesel nut; Oct 17, 2007 at 08:36 PM. Reason: MISTAKES
Thread Starter
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Tuned
Joined: Aug 2006
Posts: 327
Likes: 79
From: Runnells, Iowa
What all is involved in the install. Looks like to me you have to pull the v/c's off and install the additional block that goes on top of the head, and run the neccesary control wiring. You dont have to pull the cly heads to do this install do you? I assume the blocks that go on top of the cly heads have the actuating device in them? Am i right in saying the jake brake works by controlling the opening and closing of the exhaust valve? Im just guessing but it would make sense if the device keeps the exhaust valve closed on every other complete stroke of the engine. I'm fairly knowlegable in engines but don't have a lot of experience in these big 855's.
Last edited by Diesel nut; Oct 17, 2007 at 11:44 PM. Reason: MISTAKES
The Pacifier
Joined: Jan 2003
Posts: 8,245
Likes: 7
From: Cloverdale, BC
Okay... It goes like this. Valve covers, Jake, Rocker housing, Head, Block. Pull the valve covers. Under that is a rocker housing. Leave that in place, but there are plugs that need to be removed, they are 1/8" pipe thread, with 3/16" hex heads, to be removed by allen keys. These will supply oil to the jake.
Before you install the jakes, you might as well do a valve set, as it's all open at this point.
Once the valve set is done, get your new gasket, and install the jake heads. I hope you are not just putting a "used" set on, and at least using a matched set, and putting a spring kit in it. I can't think of the torque spec off hand, but 75 lb ft is jumping out at me. The jake set should be on the tag, but is typically 0.023". You'll need a feeler gauge that is shaped like an L to get it.
After you got the jakes torqued, and set, you can wire them up. Make sure the inside wire is connected. I have not missed it yet, but I have heard of others doing just that. Then, you can install the valve cover.
I'm off to bed, but I'll answer any more questions you may have tomorrow night.
Before you install the jakes, you might as well do a valve set, as it's all open at this point.
Once the valve set is done, get your new gasket, and install the jake heads. I hope you are not just putting a "used" set on, and at least using a matched set, and putting a spring kit in it. I can't think of the torque spec off hand, but 75 lb ft is jumping out at me. The jake set should be on the tag, but is typically 0.023". You'll need a feeler gauge that is shaped like an L to get it.
After you got the jakes torqued, and set, you can wire them up. Make sure the inside wire is connected. I have not missed it yet, but I have heard of others doing just that. Then, you can install the valve cover.
I'm off to bed, but I'll answer any more questions you may have tomorrow night.
Postmaster
Joined: Feb 2003
Posts: 4,043
Likes: 4
Originally Posted by Diesel nut
Im just guessing but it would make sense if the device keeps the exhaust valve closed on every other complete stroke of the engine.
.
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I might be wrong, but I believe the jake works by cracking open the exhaust valve at or around TDC to bleed off compression. This forces the engine to do the work of compressing the intake air (there is no throttle on a diesel so it's ingesting the same amount of air as if it was a gas engine at wide open throttle all the time). Then, before that compressed air can act as a spring and push the piston back down, the exhaust valve is opened and the pressure is bled off. This provides the 'compression braking' effect that a diesel does not naturally have.
This is also why there is a noise problem when using a jake. You're venting the air at it's highest pressure so there's a larger shock (sound) wave going out the stack.
Posting Guru
Joined: Nov 2004
Posts: 2,155
Likes: 1
From: sunny fla sometimes windy
That ain't a noise problem that is music!! You got the idea right open at TDC. Mack
does the stealth jake which is a exhaust brake and the jake paired together, It sounds
crazy definately quieter and more powerful braking action.
does the stealth jake which is a exhaust brake and the jake paired together, It sounds
crazy definately quieter and more powerful braking action.
