What engine lasts longer?

[Hammerhead]

(01-05-2019 )Rawze Wrote:  <snip>... Things like the dulled out low-end response an S60 has, lower HP curve, good HP and pulling only in the higher rpm ranges, etc. - Problem is no one wants their ISX to run like an S60.

I.E. it is not the engine design that make it last longer,... it is the dulled low-end response...

The full scale implementation of the VGT has caused everyone to despise that most despicable thing called turbo lag!!!
However, the turbo lag played a huge roll in engine longevity. Pre-spooling a turbo for increased right foot to seat of pants feedback, results in mechanical stress resistance. This increased resistance has a price...longevity.

Engine design is an endless series of compromises, you simply can't have everything.
Let's play...
Increased stress = increased wear.
There is no way around it.
So to compensate for the increased wear we need to make the components stronger to maintain longevity.
Ok, in order to make stronger components you need more material.
Ok, more material means the engine just got heavier.
Oh yeah, more material also means it takes more physical space, so it also got bigger.
Huh, now we've made it bigger and heavier...
Now we've increased the physical effort required to make our now bigger and heavier engine respond quicker, so now we have increase something else to compensate...
I know, that's easy! Higher compression reduces response time...
Uh oh, now we've increased the physical stresses again.
shi#t, back to square one...

I could type for days with flow charts like this designing an engine. I actually have spent weeks doing exactly this back in go fast days.
What are the shock load capabilities of various piston component materials?
What are the shear characteristics of this type of steel to use for wrist pins?
Hey this material will work better, but it needs to be 30% larger diameter to handle the forces, do these pistons have enough material to bore out the wrist pin bosses to allow the use of this new wrist pin?
Will the piston still handle the physical exertion after we remove the material?
Will the small end of the con rod accept the oversize pins?
With the reduced amount of material, how much have we shortened the life cycle of the rod?
Is this acceptable?
Now that we've increased the weight of the piston end of the con rod, we have to add weight to the crankshaft counterweight to maintain dynamic balancing...do we have enough material to drill a couple of holes to install tungsten slugs?
Why tungsten slugs? Cause the tungsten is twice as heavy as the crank material, so we can add weight without increasing dimensions...
Why are we so concerned about the crank dimensions?
Because we spent a week building a crank scraper plate that just barely clears the crank to "scrape" the oil off of it.
Why did you do that?
Because we want to use the weight of the oil on the crank to help pull the counterweight down thereby increasing crank force with free hp, however at the bottom of the swing, we now want to scrape the excess oil off of the crank because we don't want to waste the physical effort required to lift that oil on the counterweight upswing (parasitic drag/negative hp).
...
Does your head hurt yet?

[Ryeguy475]

I own a isx 871 and it’s been a money pit, it did make it to 534k miles/ 22k hours before I had to inframe it. Before that it was vgt turbo replace and emissions problems. After the in frame I had (still have) a vibration that appears when engine is under load. Broke crankshaft. I can’t say if any of these problems were caused by poor tuning when it was d-leted or what. It has been well maintained though, oil & all filters changed every 10k Miles. (Its always done local work) . A good friend of mine has a 2007 14l series 60, he had the egr deleted and put a single stage turbo on it & he loves it. I’ve been thinking about taking my 871 out & transplanting a N14 in lol

[Fixmytruck123]

In my opinion there is no replacement for displacement. You want big power and long lasting you need something like a QSK or similar.