Flat tappet cams

[dsmith41]

Could someone please explain to me the difference between a flat tappet cam and a regular modern cam design like we see today. I understand flat tappet engines need more ZDDP for anti wear but I don't understand where that extra wear is coming from.

This is what I think of as a modern cam. How is a flat tappet cam different from this:
http://www.youtube.com/watch?v=TEHpIbDwtvE

 

[CourierDriver]

way to tech for me, sounds good, I m not into to flat tappet cams, but I know the nation will be waiting for this, do u?

 

[gtx510]

uh, a flat tappet cam would block. cam, lifters, pushrods, rockers, all that stuff isn't in the animation

http://www.google.com/search?q=flat+tappet+lifter it's called googling

http://www.compcams.com/technical/FAQ/FAQLifters.asp

 

[punisher]

That Youtube video is of a flat tappet cam as well. It just happens to be an animation of an overhead cam vs an in block cam/overhead valve setup.

 

[gtx510]

Looks more like the solid lifters (tappets, cam followers, etc) that OEM's like Mazda and Toyota have been using for a decade or 2
Ford calls the D-A-M-B (direct acting mechanical buckets), they use them in the Duratec. I think they also used them in the later Zetec's. Nissan uses them in the VQ, they hit the new VQ37VHR ones with DLC

flat tappet cams are for amurican v8's, and they're in the block

 

[mechtech2]

This term is used to denote whatever anybody wants.
The truth is that modern designs are often flat tappet, even with overhead cam engines. Some cams use roller lifters.
If it is not a roller lifter cam, it is a flat tappet cam.

Problems are with strong spring pressure , high lifts and opening rates for high performance, when used with flat tappets/lifters/buckets.
Oils are castrated enough so that 'hot' cams may need more additives.

 

[labman]

Originally Posted By: mechtech2
This term is used to denote whatever anybody wants.


There seems to be a lot of that.

 

[JetStar]

In pushrod engines the Rocker arm ratio also increases the pressure at the cam/tappet interface. Pushrod engines typically need stronger springs than a direct actuation OHC because they have more reciprocating mass (i.e. rockers and pushrods) in the valve train. OHC engines can also use multiple smaller valves to reduce reciprocating mass instead of opening fewer large valves as on a pushrod engine.

 

[CourierDriver]

I glad somebody knows this stuff,,,I dont