Hypothetical question about a fan clutch

[Nilao]

Not sure on the 2350 but it could be a normal sound. I know my 871 has more of a old school sound after it was done.

[Rawze]

(05-22-2019 )ababajoni Wrote:  I have a question so I demandated last week but engine when I start it for the first second is as quite as it was before I demandated then the tapping kicks in as if it needs the overhead ran but it was done at time of demandate 2014 kw cummins 2350 demandate done in Ga you guys know where. Had a mechanic tell me its needs to have over head ran again, so does it get a lot nosier after demandate. Truck runs great no other issues. sorry about asking in your question still haven't figured out how to start my own ?

If your referring to Mr.Hag's shop is who did work to it, then I can only assume that no mistakes were made(would be very rare), the engine was tested, it was test driven, adjusted, including the overhead valves adjusted, boost and pyro gauges installed, fuel pump checked, and everything else done in the ways to ensure there is no loss in engine longevity.

With a correctly made de-mandate, the turbo will no longer be used by the ECU to choke off the exhaust, putting the engine under load, so that it can rapidly warm up those 'cans' that are no longer present under the truck. On those newer 2250 and 2350's, the sound of the engine will certainly change because of this, and is typically nothing to fear. The benefit of the entire engine running in a more relaxed state will now allow it to use about 1/3 the fuel at idle than it did when everything was wound up tight, especially at idle. The down side is that it takes longer for the engine to warm up in the dead of winter, as it is using a lot less fuel to keep it running.

Since we are on this particular subject, I though I would dig deeper and also mention that a couple people have asked me about valve-seat and other wear in the top end being accelerated due to this. I know it would certainly concern me, so I spent some time checking several people's trucks after they had been set this way and the wear rate form year to year really did not change by anything that could be measured. As a safety though, I have always recommended people adjust their overhead valves every 250k miles (every 2 years for most trucks) instead of 500k miles just to keep the fuel mileage at its peak and to be certain that the valves clearances do not get tighter due to this type of wear.

A person can easily measure their valve-lash wear rate by measuring the valve clearance with a dial indicator, then measuring it again every 50,000 or so miles interval under the same conditions (temp, etc). Do this for a year or 2, across a typical 250k mile span (do not adjust the valves during this 250k miles of testing) and with this info, they can calculate how long the head will last with concern to valve seat wear rate.

What you are most likely to find is that a factory 'stock' engine actually has a higher valve wear rate every time when compared to a de-mandated engine where everything is relaxed. - Why? -- the soot monster in a stock engine takes its toll and wear in far worse ways than the slight differences in how tight the engine runs at idle.

In my own truck, I had this taken tis to the extremes to try to get the absolute least amount of fuel at idle possible. Mine is set so low that it only uses about 11-12 mg of fuel per stroke vs the 40+ mg/stroke it did when it was stock. My engine actually rivals my thermo-king APU in fuel consumption. I got 960,000 miles out of my head/engine and it still did not have any amount of accelerated wear that would have been of any concern by doing this. if I had not had an injector cup getting leaky (unrelated), it certainly would have made it well past the million mile mark. Anyone is more than welcome to watch my re-build series and speculate on how my engine did over the long term with it set in these ways.

[ababajoni]

Thanks Rawze Now I feel better and wont let the different sounding engine bother me, yes it was mr Hag, I am planning on running a gallon of gear oil on oil changes does it matter if its 80w 90 instead of 85 /90

[Waterloo]

Maybe you were hearing the air compressor? She has a distinctive knock....

[ababajoni]

no waterloo this sound wasn't the air compressor it starts exactly one second after engine start up and always there unless I push clutch in and coast so its just has to be the difference in tone the engine makes now, after demandate you know you get to know the sound of your engine so now with the change it just seems weird but at least I know why it sounds like that.

[Waterloo]

(05-23-2019 )ababajoni Wrote:  no waterloo this sound wasn't the air compressor it starts exactly one second after engine start up and always there unless I push clutch in and coast so its just has to be the difference in tone the engine makes now, after demandate you know you get to know the sound of your engine so now with the change it just seems weird but at least I know why it sounds like that.

LOL! I know, it is a totally different motor than what you are used to. ;-)