Eagle Forged Stroker Crank CRACKED
Thats interesting. They market that particular damper for mild street builds up to 400hp. It seemed like I fell within that and while this motor has had some WOT pulls while tuning, it never over 5000rpm or demonstrated any strange vibrations. Its in a 6500lb full size truck 2000 Ram 1500 4x4.
Right. But as was noted above, they don’t know Jack **** about YOUR rotating assembly. Bob weight matters. So does the natural frequency of every single part in the system.
So let’s say you start the engineering with stock rods, a cast piston, cast crank and say 6000 RPM max. Then you engineer the damper to dampen the frequencies that that do the most damage.
Now you (not YOU in particular but you as in anyone doing this type of thing) drop in a steel crank. The resonance frequency of the steel crank is far different than that of the cast crank. The damper wasn’t engineered for that particular frequency and bad **** starts happening.
Now throw in a set of forged pistons and a set of 4340 connecting rods, which is not only a different materiel but is a different design. All those pieces now have a different resonant frequency than the parts that were started with, and they could easily pissed off and do very bad things.
As Randy Neal of CWT Industries says…once you excite one part of the system it doesn’t stop.
Damper technology is overlooked. Guys spend thousands building an engine and slap a 200 buck (or cheaper) damper on there and hope for the best.
And cost isn’t the best way to chose a damper either. There are some pretty expensive elastomer dampers (other than the ATI) that I would trust as a door stop.
I put hundreds of runs on stock 318 Poly cranks at 8500 (sometimes a bit more) and never broke a crank. I lost some bearings and hurt them, but I never fractured a crank. And I was wet maging my cranks as part of routine maintenance so if one started getting pissed off I would catch it.
