Jacobs Engine Brakes

The only good thing to cum outa cummins
Iz Clessie Cummins Gr8 invention the jake brake
we have used m on all Screemin GM/Detroit diesels @ 'B' Model Macks
Later the Mack used there V: Dynatard

the simplest description of how it works is to say
it converts the motor to a compressor n it punches the valves open near TDC (n Th@'z the noise) if it didn't releive pressure it could build up pressure till a head or sumthing would/could let go
By multiply n it out by wot cog U're in, it can hold back on hills without useing brakes
normally ifn U kno the Hill/Rd/Load U can change down/up near the same place goin the other way pullin uphill
the most problems we ever had with the jakes is the wiring under the rocker covers, they cum loose or fall off the connection
the only major problem is when one of our drovers twaz stuffin round driven down hill on the jakes n thort might as well pull the engine stopper
it stufft a cupla injectors as no fuel was being squirted in to cylinders n the heat burnt the tips of the shoot n irons, normally when u run off a hill on the jakes the injectors get an idles worth of fuel to keep m from burning the tiips
Jakes have got a bad name for noise mainly from cowboy/hoons turn n ther mufflers up side down to give m a good note n rub the general public up the wrong way n th@z why we now C signs to restrict the use of the jakes
2 advantages of rollin down a hill on the Jakes is:
<1> Ifn U loose all electrical power the jake will cut out
<2> Ifn U loose all oil pressure rollin down a hill on jake it will cut the jakes out also
But haven said th@ U should have guages, lights n buzzes to warn U of any of the above failures

Cya
[ch9787]

I read somewhere that in the early days towns in the US were puting up signs that said "Residential Area - Don't Use Jake Brakes" but the Jake Brake company wasn't happy about the use of their name and had them change it to "Don't use engine brakes"... They even had a 'dob in a Jake Brake sign' thing going!

I might go for a drive around the block right now and use the jakes all the way...

-Stu

I remember a mate of mine had a 903 in a 3070. The camshaft went on it, and they whacked a new camshaft in it, but the bits of the cam must have gone through the bearings. It was like a GM, the jakes used to cut out automatically at idle when the oil pressure dropped off.

OK
a request
Ifn U may
haz any body gotta better pic n dimensions of this Jake Brake emblem doodadd



Thanx to Sarge for de Oshkosh pix
Cya
[ch9787]

OK
a request
Ifn U may
haz any body gotta better pic n dimensions of this Jake Brake emblem doodadd

Thanx to Sarge for de Oshkosh pix
Cya
[ch9787]

hmmm....even tho you on tha otha side of tha fence....i think i might still have a couple of them in tha archives....if ya dont tell chocs i'll havva look and let ya know
newto

Few pages from a booklet dated 1971.

Eye reckon your wish could come true
Take a luuk here
community.webshots.com/photo/fullsize/2214969820080251109Nxquoq

Chris

K-Tron Chris
Gudday M8

U dun well Thanx 4 th@
now all we need iz the xact measurements of the jake stiker
n may B a pic taken straight on
Th@ way we may B able 2 reproduce it by pixel manipulation Etc

Cya
[ch9787]

Not a real good photo Swishy, hopefully someone has a better one.



175mm wide
100mm high
50mm high on sides.

Good stuff Loadstar!

Stand-by Swishy!