off topic, but i need help...

PoweredByDodge

nothing is ever easy...

perfect example - flat tappet lifters = 3 dollars each. flat tappet cam = 90 bucks.

roller lifters = 20 dollars each. roller cam = 200 bucks.

can't put flat lifters on a roller cam... can't put a flat cam under roller lifters. so yuou're fooked on replacement parts because life just sucks.

hellohello

whats flat tappet?

PoweredByDodge

instead of the lifter having a "roller" wheel on the bottom of it - that it rides on the cam shaft lobes with - it is just a flat solid hunk of steel. as it rides on the cam it "Seats" itself... problem with these is that you have to constantly make sure they're in adjustment... when you do your plugs each year or whatever you have to pull your valve covers and inspect lifter travel and ****. pain in the ****.

Jstas

PoweredByDodge wrote:

... problem with these is that you have to constantly make sure they're in adjustment... when you do your plugs each year or whatever you have to pull your valve covers and inspect lifter travel and ****. pain in the ****.

That is only for solid flat-tappet. Hydraulic flat tappets do not need regular adjustment...in most cases.

The cam materials between the two types of valvetrain are no different though. The reason you can use flat tappet lifters on a roller cam is because the lobe inclines are too steep for the flat tappet lifter to follow properly. That is why roller cams are teh high performance option for the street. They can handle a more aggressive cam profile and the valve opening and closing is more progessive with a roller cam than it is with a flat tappet. However, because of the roller lifter's ability to follow a more aggressive cam profile, the valve can open and close much faster than a regulat flat tappet hydraulic lifter.

Now, start talking about solid flat tappets and roller cams look like weaksauce in comparison. I have seen solid roller lifters and they are usually reserved for race applications with constant, high RPM use like in oval racing. Solid lifters though, they are pretty much a race only application anymore. They require too much maintenance for the street and since average joe blow has no clue what they are doing under the hood anymore, it save the car companies a boat load of warranty work by making things fairly maintenance free. However, solid lifters are a more accurate way of actuating the valve and they can handle very aggressive cam lobe designs. They also can withstand the great force that a more aggressive slope creates.

That slope dictates alot though. That slope determines how fast that valve opens and closes. The faster it moves, the more forces there are involved. Not only does teh lifter and pushrod have to be strong enough but you rocker arms need to be strong enough too along with your valves. Keep in mind too that the faster that valve opens, the more force is needed to counter act that opening so that it doesn't get shoved all the way into the combustion chamber but it can return just as quickly to a closed state. Hence teh reason for tandem valve spings and such. Valvetrain springs need to be extremely strong to withstand the pressures of that valve train. I know it doesn't seem like alot but keep in mind that when your engine is running at it's redline, we'll use 5700 RPM as an example, that entire rotating assembly, valves, piston, rods, crankshaft, camshaft and so on is turning at 5,700 times a minute. That is almost 100 times a second. That means that that valve is opening and closing twice as fast. That is a HUGE amount of stress on that valvetrain so the parts need to be beefy.

PoweredByDodge

it's kind of wild when you think of it that way - 10,000 times a minute that valve is opening and closing... that's sick.

... so if i follow you - in an ideal world, a solid roller cam would be the best? --- can handle a steep cam and also take the stress of wicked high rpm's.

... **** - i could have gotten solid roller lifters for a lot less than the damn hydro ones i bought. son of a *****.

hellohello

ok, so i understand the whole engine is an air pump idea, the fact that if u can get more air into an engine itll run better and more efficiently, but what about the exhaust... ive seen things like equal-length headers that are supposed to give more horsepower, along with cat-back exhaust pipes, if i remember correctly these things are supposed to increase back pressure giving a lil more kick... and the equal headers even out the atmospheric pressure "seen" by the engine... (aint google great?)
Ive mentioned before about my neighor with the 80 something f150, i told him about the gas mileage my old man saw when he used a more open carb lid, and my neighbor asked me if a better exhaust would help that situation... i knew it would increase horsepower, but efficiency I wasnt sure. He has a dual pipe air intake thing and as far as i know no one makes an aftermarket replacement, unless u get 2 of those pipes with the right diameter and hook them up... but that sounds like it could be troublesome...