I had a Cat Mechanic tell me today that my exhaust brake I just installed will burn the valves. Has any one had this problems with a exhaust brake on their trucks? I installed a Pacbrake PRXB brake.

 

I don't see how. Foot off throttle, no fuel, etc....seems like another clueless mechanic....

MikeyB

 

I too have th Prxb and was told that Pacbrake can only use the specified backpressure allowed by cummins.

 

maybe he wants you to buy a CAT.

 

That part is true. Cummins has a max back pressure rating that must not be exceeded and Pacbrake meets that spec with their factory set pressure on the internal pop-off valve in the PRXB. But that has nothing to do with burning exhaust valves and seats...only for floating the exhaust valves. Burned up exhaust valves and seats usually has more to do with very retarded timing and high load/EGT. But you will usually get a hole in a piston before there are any valve and seat issues on these engines. So yeah, I think that mechanic should just stay working for CAT.

 

Thanks guys I have never heard of problems with burn valves before, so thought I would check.

 

i have had my prxb(2nd one actually) since the truck had 500 miles on it... 43000 later, no issues.... ever.

 

Does any one know what the max back pressure rating is? I'm going to bulid my own exaust brake, and this would be a good thing to know.
Thanks.

 

Thats some mighty fine glue he sniffs, lol no the pacbrake will not cause this kind of problem.

 

Harold. I read somewhere on hear that a guy was told by Pacbrake that the PXRB does not operate with the fast-idle. Is that true?

 

It is true that the brake is deactivated when the fast idle is on, as it is detecting fuel in the TPS. However there is a way to bypass this on some Cat engines with a relay.

 

my pacbrake works fine with fast idle. both automatic and manual (cruise control) high idle.. i can have the brake on from normal idle to 1100 rpm.. once temp gets to 170*, the brake kicks off.

 

Me too. As long as you don't increase the engine speed TOO much the exh brake stays on.

 

He is probably one of those people that will tell you that an engine or exhaust brake will hurt your fuel mileage too. You have to wonder about some of these mechanics.

 

Sweet!! That is what made sense, as that's how my Jacobs works.