Do You Have a Decelomatic?

[thane]

Does anyone else have a Decelomatic on their motorhome?
My 1977 Class C has such a system and after weeks of trying to figure out what it was, I stumbled onto its inventor and had a nice talk.  He also invented a Marvel Mystery Oil Injector that is on my motorhome.
There is a vaccum driven switch in the engine compartment and three control switches in the cab.  A large vacuum line runs to a pressure control valve mounted away from the engine.  There used to be a one or two valves in the exhaust pipes (either 1 before the muffler or one off of each header) but those were missing on my motorhome; probably removed with the last muffler replacement.
When going downhill the driver would arm and turn on the Decelomatic and when his foot was removed from the accelerator the exhaust valves would close and the vacuum pressure in the intake manifold was controlled by the pressure control valve to provide engine braking.   The third switch is so the operator can cycle the exhaust valves to burn off soot and carbon build up.  The Mystery Oil Injectiton system would help with the soot removal.
If you have one of these note that the pressure control valve is labeled “Experimental Prototype”.  They were labeled this way for legal reasons.  The inventor said they sold about 4,000 units.

[Stripe]

You find those on Big Rigs now as exhaust brakes. A couple of the trucks I drove in CDL school had an on off switch for that.  Pretty cool deal..  Although they aren't allowed to be used in certain areas now due to noise restriction.

Fredric

[Froggy1936]

AKA Jake brake Very noisy By blocking the exaust the engine has a hard time releiveing the compression Increasing the deceleration hold back by a lot Its important on a rig weighing over 35 Tons  Frank

[thane]

I found the missing exhaust valves, they are built into the header.  I am going to buy the manuals and maybe get it operational.