Series 60 Jake Retrofit Article

[James77MCI8]

Thought this might be of some interest to you guys and gals.

http://www.jakebrake.com/support/docs/Retrofitting.pdf

[TomC]

One of the main reasons Detroit came out with the new DD13, 15, 16 liter engines is to have the Jake brake built into the engine.  And to have a separate lobe on the exhaust camshaft (dual overhead camshafts-one for the intake valves and the other for the exhaust valves and Jake brake) to operate the Jake.  On all other engines (except the Cummins ISX which also uses a dedicated camshaft lobe for the Jake brake) timing is done through the injectors.  Hence-the injectors pop open at the top of the compression cycle and when the Jake is activated causes the exhaust valve to open at the same time releasing the high compression pressures suddenly and with lots of rapping noise.  This is what makes for braking power.  With stricter and stricter noise laws, Detroit decided to redesign the engine to both with stand more compression pressure (higher efficiency) and to redesign the Jake brake.  With its' own camshaft lobe to open the exhaust valve, the exhaust valve is now opened during compression stroke gently allowing the compressed air to escape and almost completely eliminating the familiar Jake brake exhaust rap.  The way it works is very simple-there are two exhaust valve rocker arms and camshaft lobes (hence no rocker arm bridges to adjust) per cylinder and the Jake rocker arm has a hydraulic lifter built into it to open one of the exhaust valves.  When the Jake is activated the hydraulic lifter fills with engine oil pressing the Jake brake rocker arm against the exhaust rocker arm causing the exhaust valve to open for the Jake brake operation.  Very simple, powerful and quiet.  Good Luck, TomC