I'm just trying to learn here, not buying, not yet anyway's.

I got the following answer from CFI-EFI on another thread about heads so I wanted to start another threat.

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The Hydraulic one" can be either flat or roller. "The flat tappet one" can be either solid or hydraulic. But as to why a roller cam is more desirable than a flat tappet cam, simply stated, the roller lifter allows a steeper acceleration ramp than a flat lifter. Because of this, a roller cam can have a greater lift and a greater area under the curve for a given duration than a flat tappet cam. ----------------------------------------------------

I'm honestly still a bit confused, but I know the solid ones aren't very popular because they make a LOT of noise, so I won't really look any deeper into that one.

The hydraulic ones, roller or flat tappet, I understand the words and the explanation, but not really what the parts look like and how they work in comparison.

Can any one guide me a web site or have some pictures to make me understand.

Thanks!

 

Does my 88 Vette have the Flat tappet or roller cam?

 

Check out this link: http://www.compcams.com/catalog/
I don't recall if they have pics or not but their hard cover catalog does.

The important issue is that a cam starts out as a rod which is ground down down in diameter to a certain base diameter (base circle) with periodic bumps or lobes and larger diameter sections (bearing races) left along it's length terminating in a dist gear at one end and a gear attachment at the other end.

A flat-tappet cam has sloping lobes so that as it rotates the flat surface of the lifter bottoms tend to push the cam toward the rear of the engine, so that the cam doesn't "walk" forward; this lobe slope also causes the lifters to rotate which evens out lifter wear extending lifter life.

Since the bottom of this lifter rides on the cam lobe directly, too steep a slope on the lobe causes excessive wear. This limits the steepness of lobes and so the speed with which the valve can be opened or closed.

A roller cam is made of hardened steel to minimize wear; since the lifters have rollers on their bottom end, the cam lobes do not slope as this would cause the lifters to rotate and destroy the rollers. Since there is no rearward force on this cam a cam button (or other device) at the front is used to keep the cam from walking forward.

Since here the lifter has a roller on it's bottom, it only contacts the cam along the line where the roller rides on the lobe. This allows rather steep lobes which makes for "agressive" cam grinds which open and close the valves rather quickly.

A solid lifter is simple a cylindrical pieceof steel machined to ride on the cam shaft. Be it roller or flat tapped on the bottom, the body is solid; so it transfers the cam profile directly to the pushord. Though this type of lifter follows the cam profile at all engine speeds till valve float, wear of valve train parts necessitates occasional adjustment of valve lash.

A hydraulic lifter (either roller or flat-tappet) is hollow and uses motor oil within it's body to transfer cam motion to the pushrod. This oil, due to internal valving maintains valve train adjustment. But at very high engine speeds the internal fluid can become trapped within the lifter causing lifter "pump up", which can disrupt valve train operation.

I hope the reference and this brief overview is helpful.

 

http://www.newcovenant.com/speedcraf...camshaft/1.htm

 

You have a hydraulic roller, thats all you really need to know. Your combination will not be nearly serious enough to warrant solid.

 

Thank you

It answer my questions! :thumbs:

 

Here's what I suggest. Since you seem to really want to learn about engines go to the websites of CompCams, Crane, Manley, SummitRacing, JEGs and as many others as you can think of. Order their catalogs, which in most cases will be free.

The catalogs have all sorts of information about different components for your engine. There are photos of different parts so you'll be able to readily identify them.

I also recommend you buy TPIS' Insider Hints book. It has a lot of information about the TPI setup, dyno and flow bench data, It's not free but well worth it if you want to learn about the TPI engine.

If you're like most of us, the more you learn the more you want to learn.

Hope this helps.

Jake

 

For those that didn't see the origional thread, I thought I would repeat it in context.

The question was: Followed by the answer:RACE ON!!!

 

Great answer CFI-EFI, I couldn't have put it better myself! :thumbs: