Comp QXI Lobes

[digger]

Wonder why they don't just play games with the advertised numbers instead of sticking to the industry standard of 0.006" for adv duration? Since everyone that reads the magazines wants short advertised duration for a given 0.050" duration, why not just design lobes that work and published advertised numbers measured at 0.009" or something? I think Isky does something like this.

Because if someone has it measured, and it's not what Comp said it is, it's Comp's fault. If it matches the specs, and beats the hell out of the valvetrain,
Maybe it's the lifters? Maybe it's the rockers? Maybe it's the pushrods? Maybe it's the lifter bores? maybe it's the lifter bore clearances? Maybe it's the oil? Maybe it's the valves? maybe it's the valve seat? Maybe the engine builder should have known it was to aggressive for his application?
It's called "Plausible Deniability"

Depends, is there a commercial available valvetrain setup that would live as expected ? What are the recommendations made for component selection for the lobes ?

[Tom Walker]

The engine in the video clip sounds just like a diesel

[406shark]

The engine in the video clip sounds just like a diesel

That's what I was thinking when I listened to it.

Can you imagine if that small block Mopar had sheet metal valve covers instead of those thick cast aluminum ones? I don't think I've ever heard even a solid lifter setup sound that loud.



Jeff

[n2xlr8n]

No.
The force that is hammering the valve open, and slamming it closed, is the issue.

Mike answered it with this. Its not the lifter its the valve hammering the seat. Correct me if im wrong

Correct. The plunger is getting hammer also, but that's not what you hear. The issue is the valve hitting the seat, and the rocker hitting the valve tip.
Now, when the plunger is getting hammered, and collapsing, it can actually increase the velocity/acceleration rate at which the valve is leaving and hitting the seat.

Thanks for the clarification, fellas.

[Elroy]

The fast Comp hydraulic roller lobes will make some power if you can keep them happy////and don't mind the noise///or just put solid roller lifters o them

[paulzig]

The engine in the video clip sounds just like a diesel

It'll have some low down TQ then