Originally Posted by clinebarger
Originally Posted by OVERKILL
My dealer has done a few, though none of the tech's I've spoken to refer to it as "common".
Cue burla, as he's all over this.
Also worth mentioning: They've never done one, or heard of it happening on the SRT 6.4L, despite the lifters being the same part #.....
I'm not sold on it being a lifter problem, The surface hardening or lack-of on the Camshaft is where my theory lies. Every Hemi failure I've seen is on a Cast Iron core (Selectively Austempered Ductile Iron) which is a fancy way of saying Cast Iron with hardened work surfaces.
Pre-MDS 5.7L Hemi's used 5150 Billet lobes & journals pressed onto a hollow tube. I had a isolated incident with with one of these on a Mopar Performance Crate engine......Number 3 cam bearing was installed/clocked incorrectly from the factory, Starving the journal of oil. The cam journal seized to the bearing causing the journal to break loose from the tube.....Not before shearing the cam gear locating dowel causing the cam gear to rotate about 30 degrees out of time.
Mopar warrantied the engine!
Supposedly the SRT cores are SADI as well though...
My theory is spring pressure, as that's the major difference, the SRT's have heavier springs. I'm thinking light springs causes float, hammers the roller, roller sticks, breaks through the hardening on the lobe, and boom, it's a hot mess. I've seen a roller fail on a billet shaft and the cam faired surprisingly well in comparison.
Enough float (which rollers hate) could also cause the pin for the roller to shift, jamming up the roller.
Back when I was big into the SBF scene a ton of aftermarket sticks, including the one I ran for a stint, the TFS #1, were SADI. If you bought a custom grind, you could get billet, but a very large cross-section of the aftermarket cams were SADI and nobody was wiping lobes unless a link-bar broke and the lifter rotated.
