Neither will a simple ball bearing- unless it's specifically designed for side loading (thrust). See: [link]http://www.nsk-corp.com/page.asp?ID=252[/link] and note "Angular contact". While a standard ball bearing will take a moderate amount of side load, this is not the specific type of loading they are designed for- unless the bearing in question is indeed an angular contact bearing.

That being said, you'll need to determine if the engine has an adequate provision(s) for thrust loading. This notwithstanding, rollers are fine and will support a higher axial loading than ball bearings- albeit with a lower top RPM limit.