Loose injector adjustment

[Hammerhead]

(01-13-2020 )AussieISX Wrote:  ... I actually set mine slightly tighter than spec for the reasons I listed.

(01-13-2020 )tree98 Wrote:  So tightening the injectors doesn't put more pressure on the cam ? Sure seems like it would.

The injector pre-load that is set an 8Nm is the closing pressure of the pintle into the seat of the injector tip. 8Nm is not a very high torque value for a "needle & seat" as it is a tapered contact point. As long as you're only increasing it "slightly" (I don't know what value he's using, I'm just speaking in general), you wouldn't be adding a large stress to the cam/follower. An injector cam is not shaped like a valve cam. The high lobe is a larger percentage of the cam than the relief as the injector is held closed until it is "time to load" the timing and metering areas, then the cam relieves the pressure, opening the injector to be filled, then the cam drives the fuel into the charge mix for combustion...this is when the most pressure would be applied to the cam/followers as the cam/rocker/injector must produce enough physical pressure to overcome the compressed charge mixture near TDC to not only inject the fuel but also atomize it for optimal combustion, which other than during the combustion stroke is the point of peak cylinder pressure...