There are a lot of reasons not to like the SKF
if they can't take impacts as good as the others then its just another scratch against them
the roller end radius is very sharp 1/3rd that of other bearings so when taking end loadings the tendancy to dig in and misalign is worse.
actual problem in the bergs is probably not just misalignment but that misalignment coupled with the rollers contacting the lip on the inner race from crank flex, wandering endfloat or poor engine build. in those situations you have both skewing of the rollers and increased stresses on the roller ends.
although roller to lip contact is not mentioned in the rollway bearing literature they do say that deflection (crank flex) is the worse of 2 evils because of the stresses on the roller ends.
IMHO bigger end radius = longer life in a worst case situation = don't use SKF.
the SKF C3 range is very broad too Ive found some too tight and others too loose still having C3 on them, while other bearings like orangebergs specials can be speced to have exactly 46 microns clearence
ABMA standards state that optimum dynamic capacity C values refer to roller bearing mountings so designed and executed that uniform load distribution over the active roller length is assured. it is further stated that if misalignment is present a reduction in the capacity value should be made.
2 types of misalignment: A location misalignment, and B deflection misalignment.
location misalignment implies misalignment in a plane at right angles to the direction of the load. this type is assocoated with skewing of the rollers on the roller track and resultant distortion of the contact area. location misalignment may arise as a consequence of 2 bearing supports some distance apart being out of line. though very undesirable this type of misalignment is not as serious as deflection misalignment and does not result in large bearing capacity reduction.
Deflection misalignment misalignment in the same plane as the direction of the load. this type is ascocitaed with a tendancy toward digging in of the roller ends on the roller tracks with resultant high stresses at these points. with straight non crowned, cylindrical rollers this condition is much more exaggerated than in designs incorperating crowned cylindrical rollers.
deflection misalignment is encountered when moderate to heavy external radial loads exist on small diameter shafts and/or bearing supports are remote from the point of load application"
with all that I ran the oem vc025 skfs for 170 hrs they looked fine. if everything is spoton, crank runout, endfloat, interference fit in cases and on the crank there isn't really a problem in the 628 engine. the 550 seems to have a more veracious appitite for mains, the local butchers have just got another one in
I use rollway bearings and have one of orangebergs to test.
