Cams

[5.7 hemi]

What makes a solid flat tappet cam a solid flat tappet cam? Is it just the lifters?

I’m asking cause I don’t know.

 

[andyf]

That is actually a very complicated question but it has to do with the ramp design. Different ramp designs will require different amounts of lash. The math gets pretty hairy so I'm not going to attempt to provide a more technical answer.

 

[5.7 hemi]

Let’s make it simple......you by a flat tappet cam, do you buy hydraulic lifters or do you buy mechanical lifters? Can you put mechanical lifters in place of hydraulic for a given cam.

 

[steve340]

The grinds are specifically for use of either hydraulic lifters or solid lifters. I understand you cannot mix them up.

 

[tmaleck]

The primary difference is the lobes themselves. A flat tappet cam has a slight taper in the lobes side to side. The lifters also have a slight taper across the bottom of the lifter. These tapers cause the lifter to rotate in the bore. This helps prevent wear.

 

[wyrmrider]

both solid and hyd have tapered lobes and crowned lifters
putting solids on a hyd lobe is a BVVC as there is not the usual solid lifter cam clearance ramp
more like what steve said above than not
most often done by "cheaters"
simple answer hyd lifters for hyd cams- solid lifters for solid cams- both are "flat tappet"

 

[moper]

What makes a solid flat tappet cam a solid flat tappet cam? Is it just the lifters?

I’m asking cause I don’t know.

Like Andy said - it involves the earliest and latest parts of the lobe's ramps. Short answer is hydraulics have to be slower because the hydraulic piston and oil within the lifter can't withstand a really aggressive change in lift. Also holds true for hydraulic rollers.
Solids are run on hydraulic cams fairly often, but it's not wise to run a hydraulic on a lobe designed for a solid.