Exhaust Over Heating

[acme66]

I moved the exhaust on my 923 from the stack to under the bed and out the rear corner. Didn't have a choice as the state of Montana is requiring it for what I plan to do with the truck. I went with 4" to match what was already there. Did an amazing job making the cab quieter but, and this is a big but, the piping got hot enough on a long hill climb to melt off the rubber on the muffler hangers. Whoa. I never gave EGT's a thought since it lacks a turbo. I am beginning to think I have a huge amount of back pressure. I reused my old muffler which looked fine despite being sooted up with 1/16+ inch coating inside the muffler. Again I never really gave it a thought. My modifications added 10 additional feet of 4" line but also took out one of the 90 bends, it is literally a straight shot all the way out. Wondering if I need to upgrade to 5 inch, swap to a new free-flow muffler or if I just flip the exhaust hangers around, put the rubber at the top and drive it. It has to be quiet for our business. I know most of you run stacks and so give exhaust and muffler heat little thought (nothing up there to melt/burn) but do you have any ideas? Grade was 6 miles of steep, truck did it in 4th and I was not flogging it. Engine coolant temp never got above 190.

-Ken

 

[Suprman]

Maybe you can get some hi-temp insulation or wrap to put around the pipe I have seen it for headers before.

 

[wreckerman893]

Do you know if the fuel has been turned up? On a long pull with the fuel turned up you have to back off the throttle or you will build heat quickly. A lot of diesel engines have been ruined by "diesel doctors" that knew how to turn one up but not how to keep it cool. There are several adjustments that need to be made when turning the fuel up. Have you looked at the exhaust manifold and the first few feet of pipe coming out? If they are discolored you have prob gotten the engine very hot. Did you notice any increase in water temp while pulling the grade? Just my thoughts.

 

[markmontana]

Exhaust pipes get real hot- all the way to the end. Do they use rubber on the standard configuration? I don't recall ever seeing any- so get rid of the rubber stuff, IMO.

 

[acme66]

I am the second owner since the army but as much as I have been told no motor modifications at all. She is really slow to have had anything turned up. No water temp rise at all. No rubber mounts on the standard stack but then this ISN'T the standard stack anymore. I used your typical industry standard hangers so something is not right. Thinking of replacing the rubber in the hangers with a short chain so it can still flex. The remove all the rubber concept might be spot-on regardless.

-Ken

 

[tourus]

well in 20 + years of trucking if a person lugs an engine on a long hill(pull) the exhaust will heat up turbo or not.. so try to keep the engine rpms up towards the top of the scale.. believe it or not that will drop the exhaust temp down..