firefighter2000

I know jacobs doesnt offer it for the 8.3 or smaller, but why doesnt jacobs or cummins offer a true ENGINE brake for the smaller diesels? Im not talking about the exhaust brakes, but the true engine brakes. Has anyone ever modified a larger one to fit on a 5.9? Anyone shed some light on this subject?
Thanks
Craig

wannadiesel

Engines that have a true Jake brake have cam actuated injectors. When the Jake is applied, the injector rocker is ganged to the exhaust rocker, which opens the exhaust valve for a short time near TDC. The 5.9 and 8.3 don't have cam actuated injectors - thus no Jake brake is available.

firefighter2000

Since the 5.9 has 4 valves per cylinder would it be possible for Cummins or Jacobs to engineer a true engine brake for them? Or is the cost too great to do something like that? When it engages doesnt it retard fuel flow? I guess with the common rail injection its not possbile to retard fuel flow to one particular injector/cylinder
Craig

wannadiesel

They'd need another cam lobe, pushrod, and rocker for each cylinder, I can't see how they'd work it in there cheaply.

Fuel flow is already at a minimum when a Jake is applied because the driver's foot is off the pedal and RPM is higher than idle speed.

Common rail can do whatever they want, even kill cylinders. There's a 3 cylinder cold weather warm-up feature on the 3rd gens. When the engine is very cold (under 20 degrees I think) it idles on 3 cylinders at around 1500 RPM.

dieselrob

The vp44s can kill one injector at a time to with the scan tool. It also has thehigh idle, and 3 cylinder warm up idle. You just half to get a scanner and flash it in.

dieselmech01

Isc 8.3 does have a jake brake available,it is the same basic design as a jake for a m11,l10,n14, they are oil psi fed and have a elec soleniod they dont need a push tube,rocker.

firefighter2000

So is that something that would be modifiable for a 5.9 or something that could be done with a 5.9? Im not going to be attempting it... Just curious as to why Cummins or Jacobs hasnt made one especially since the light duty pickup/diesel market has become as large as it has. I cant be the ONLY person who'd like one!

Smkndzl

Jake's do not require a second cam lobes or a cam driven injector. the ISL is available with Jakes and have electronic injectors just like the ISB or ISC. the reason you wont find jakes on the ISB is that it is still using a flat tappet lifter, the ISC for a long time was not available with jakes just for that reason. then the CM850 ISC came with roller tappets just like the ISL and also can now have jakes. both of those style use a different cyl. exh. to actuate a slave piston to open another cyl. exh. valve.