Pac brake

[George Lowry]

Hi Wallace,

I see you have got several other answers from those who have not
actually worked on the various auxiliary braking systems.

The Pac Brake, <http://www.pacbrake.com>, is made by a privately owned
company in the northwest. I believe it is homebased in Canada. The
Pac Brake is primarily an exhaust brake consisting of a butterfly
valve that is placed in the exhaust. When activated, the exhaust back
pressure acts as a braking device. It is very effective and, more
important these days, Quiet...

Someone else likened it to the Jake Brake. Only in that it provides
auxiliary braking. The Jacobs Company developed the Engine Brake,
which is commonly called the Jake Brake. It is more complex and
operates by activating the exhaust valve of the engine to release the
stored energy from the compression stroke. It is also very noisy -
makes the BRAACC noise you hear on trucks etc.

Now that he patents have run out, there are several companies that
make both the Engine brake and the exhaust brake. Each are referred
to by their original developers names, hence the Pac Brake and the
Jake Brake. FWIW, there are other auxiliary braking systems such as
the transmission retarder and the Telma retarder which is a
magnetically operated system.

I have used both the Jake engine Brake, commonly used on Detroit
engines and the Pac Brake. I had that on the GM bus conversion on a
Cummins 903 engine. I was going to use the engine brake but the
installation did not have enough room for the extended valve covers.
After using the Pac Brake, I found that we actually preferred it
because it was not restricted from use like the noisier Jake.

Hope this helps,

George Lowry
'95 WBDA 4203
Spearfish, SD

Wallace Craig wrote:

> I can't seem to find what a "Pac brake" is; it in an ad for BMC
> with no further explination. Help ?
> Wallace Craig
> 85WLPT40
> Azle, Tx
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