Cast cam and 13mm pump?

I ran a No Limit MFG cast cam and 13mm this year with no problems. It's actually a stock 24v cam that Eric re ground for me.
 
Maybe my heads in a fog right now , but can someone tell me what running a 13mm pump has anything to do with snapping cams? I can understand if your talking about spinning high rpms (4500+) for sled pulling, but drag racing and getting up to 4K rpms during shifts at max, I can't see how it would have any affect on breaking a cam?:confused:
 
Takes more effort to pump more fuel , the angle of the factory gear teeth pushes the cam to one side cast don't flex well
 
The post from Zach a few pages back explains the stresses on the cam, but not why so much.

Every lobe on the cam, every stroke of the pump, every piston stroke and every time a tire hits something is a change in the inertia of the power train. Each time this happens, the change in rotational speed has to be absorbed somewhere. If a component isn't strong enough to transfer that force (dissipate it) stress risers in that component (Zach post) will cause enough force to overload the part, and it will fail.
With a large injection pump comes high(er) torsional load, and if the inertia changes like some of these guys described, the energy has to go somewhere.

I'll probably get my ass handed to me for this, but it's what I think I know.



Something smart goes here
 
98 12valve man. said:
Maybe my heads in a fog right now , but can someone tell me what running a 13mm pump has anything to do with snapping cams? I can understand if your talking about spinning high rpms (4500+) for sled pulling, but drag racing and getting up to 4K rpms during shifts at max, I can't see how it would have any affect on breaking a cam?:confused:
Click to expand...

I am the OP.. My 1-2 ahift is around 5,500rpm and after that it's around 4,900rpm. I am tearing this motor down to go bigger with a billet cam (230/240) and try to keep alive. For anyone curious my setup worked great with a cast cam/13mm p&b pump and I ran the billet scheid cover with the bearing for the nose of the cam.
 
Levi_plummer said:
I am the OP.. My 1-2 ahift is around 5,500rpm and after that it's around 4,900rpm. I am tearing this motor down to go bigger with a billet cam (230/240) and try to keep alive. For anyone curious my setup worked great with a cast cam/13mm p&b pump and I ran the billet scheid cover with the bearing for the nose of the cam.
Click to expand...



Are you running better tires yet ?
 
97rada said:
Are you running better tires yet ?
Click to expand...

Not just yet.. I am planning on building a 96 I just bought. It will get coilovers on all four corners with a single leaf rear and caltracs. Logan Yelton and Tim Wright will be doing all the chassis work and the engine and transmission work I don't do. I plan to put it on a 30" slick then. I also have a schedule runner and O/S valves for the head. It will keep a wet block for street ability. Planning on an sxe88 and up in the air on modified non intercooled pistons or weisco's.
 
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