exhaust back pressure

[Blue Ox]

Thanks for the warning! I found some oil in my air pipe so I am going to swap turbos before it fails maybe get one with the better seals. I can hold it with the jake and keep it at 1800. I really just want some extra, more braking the better.

[Hobert62]

If the "jake" basically opens the exhaust valves in the compression stroke letting the compression out.  Wouldn't adding an exhaust break wich holds exhaust in the motor totally counter act the functions of the "jake" brake?   

[mrsmackpaul]

I dont think so

 

Im pretty sure by opening the exhaust valves it makes it not have enough compression to ignite but still make compression to work against the motor

A exhaust brake would make even more compression and make the motor compress the air even further to slow tje truck

 

Paul

[JoeH]

Not sure how far the Jake's open the exhaust valve, but they can't have it opened enough to interfere at TDC. Idle injection advance is ballpark 18°, so injection and combustion have already happened by the time the Jake starts opening. That last 18° the combustion works to slow the engine, then near TDC the exhaust valve starts to open, venting the remaining pressure generated by the combustion.  

Not sure if diesels change injection advance based on rpm.

Hobert may be on to something with the butterfly brake not working in tandem with a traditional.  The Jake doesn't dump the "compressed air" it dumps the cylinders "reward" combustion. It works to make the combustion but the combustion is vented before it can be turned into mechanical power. Thus, it's a force of resistance.

An international oil delivery truck i drive in the winter has a butterfly style, and that brake will throw you through the windshield! But that's a single axle truck, not a 107000# truck. At that weight you simply need to drive smart and maintain a safe rig. (That goes for all weights)

Edited March 29, 2019 by JoeH

[Blue Ox]

Mack had the stealth brake that was both jake and exhaust brake from what  info I can find. I know of older macks with exhaust brakes and the guy who drove them said they worked fine.

[Blue Ox]

I have everything to put the exhaust brake on. I can't find any reason it will cause major issues, like valves hitting pistons. I think I will try it, if I find any issues I will take it off.

[fjh]

4 hours ago, Blue Ox said:

I have everything to put the exhaust brake on. I can't find any reason it will cause major issues, like valves hitting pistons. I think I will try it, if I find any issues I will take it off.

Pre and  real early eteck there was An exhast brake Option called Stealth brake!!!! To install this unit( and to run in tandem with jake  ) we were  required to remove valve covers and replace or add valve seals and replace valve springs to install these!    WHY I am unsure ??? As  I stated before ! So they had us replace the valve springs and seals for what ever reason !!! ? Now having said that you could just disable the jake you don't got to use it! This combo worked well with exception of the turbo issue on long grades! if you are running on relatively  flat ground and in town type work I see this as a viable option! that said proceed with caution! you have the right approach  may  worth the while?  time will tell Guess! if it don't work you don't have to use it!

Edited March 29, 2019 by fjh

[Blue Ox]

Thanks again fjh! According to the service manual I have the e7 valve springs had to be replaced with 190 t0 210# valve springs which is what the etech standard springs are in the book. I don't have the long down hill grades like out west so I may not have the same issues. I will try it if it works good if not I try a telma.