Diesel ex. valve seat pressure

[starspangled]

I have asked Cummins and around diesel forums with no replies: there are many general references to the Cummins 4B and 6B engine's exhaust valves being 30 lbs spring stock or 60 lbs spring in HD apps. That doesn't seem near enough pressure to me, in comparison with many spark ignition gassers. What do you say, is this simply slang terminology, or is that an actual spring pressure/tension figure? Further explanations for a somewhat 'challenged' diesel owner much appreciated!

I plan on fabricating an exhaust brake with the actuator spring-tensioned to 10% below valve spring actual pressures to keep valves out of piston contact etc. Thanks,

Starspangled

 

[GregLocock]

if that is the rate then it doesn't tell you how much preload there is on the springs. In general the rate of the valve springs for a diesel can be lower than for an SI of the same size as its redline will be lower.



Cheers

Greg Locock

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[patprimmer]

If that is the seat pressure, it sounds about right for a low rpm engine with a cam profile to give long valve train life.

What is the Cummings spec. The OEM engineers probably have a rough idea of what is required.

Regards

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[starspangled]

Thank you, gentlemen! Unfortunately I couldn't get a straight answer when contacting Cummins. As a matter of fact after about 30 minutes of question and answer and dodge-ball, all I found out was that the injectors are "...the wrong injectors for that engine..." even though they are the ones spec'd on the data plate.

Your info is more than sufficient to answer my question as it just didn't seem possible to me. It's not SI, and it's all new to me! Thanks...