roller vs non-roller cam

[jerry S]

How much better is the roller vs the non roller? I currently have a hydraulic flat tap cam. What kind of gain might see by converting over to a hydraulic roller cam? I know I would have to change the valve springs. I have screw in roller rockers so I am ok there.

 

[skywalker]

The biggest 2 differences:
less friction which translates into faster/smoother revs.
Higher ramp times and more radical profiles without ruining streetability. This means you can pull more power and still seem like a street car.

If you put a roller cam on that has the same basic profile as your flat tappet cam, then you probably won't notice any gains (though some slight ones would probably show up on a dyno.) But you can get more radical with your cams and still maintain streetability (if that is your goal.)

 

[65ShelbyClone]

I agree with sky.

The roller cams' design allows faster ramp rates, meaning the valve opens faster and therefore can stay there longer. Rollers tend to have a broader torque spread in mild apps and can be more agressive before getting unstreetable. They also (usually) have a distinctive sound compared to flat cams.

What are the specs on your flat cam? Judging by your mods, its probably pretty lumpy.

 

[jerry S]

What are the specs on your flat cam? Judging by your mods, its probably pretty lumpy.

Here is my grind:

ADV DUR: INT 297, EXH 308
LIFT: INT 538, EXH 534
DURATION AT .50 DEGREES: INT 236, EXH 242 @ 108 centerline

If I convert to a roller and get better valve springs, how much "more" cam could I turn and what kind of gains might I see?

My objectives are to realize more HP and more torque than now. I am stuck with my current heads and pistons but I will upgrade to a 700 cfm double pumper and an RPM Air Gap.

 

[65ShelbyClone]

I was right, that is pretty lumpy .

If you dont have any more space between your valves and pistons with the current cam, then you wont be able to run "more" cam per se. If you get a roller with the same specs, I would guess a 10-15fwhp gain just by design. A custom cam might net you even more. This is the point where I put the disclaimer saying I'm not a cam expert, but I do know how they work.

Thats a nice dyno chart too.

 

[D.Hearne]

If you don't already have a roller cam block, the gains you'll get from a roller will not be cost effective. Cost to convert a non roller block to a roller cam, is going to run you at least $600, maybe more.

 

[skywalker]

If you don't already have a roller cam block, the gains you'll get from a roller will not be cost effective. Cost to convert a non roller block to a roller cam, is going to run you at least $600, maybe more.

More like $400 if you get the link bar lifters from crane cams. And you can use a standard base circle cam.

 

[D.Hearne]

More like $400 if you get the link bar lifters from crane cams. And you can use a standard base circle cam.

You've forgoten to add in the cost of pushrods, valve springs, and the cam, and a steel cam gear, and if going the other route, (reduced base circle cam) the tie down hardware

 

[jerry S]

If you don't already have a roller cam block, the gains you'll get from a roller will not be cost effective. Cost to convert a non roller block to a roller cam, is going to run you at least $600, maybe more.

Let's see: $300 for the cam, $150 for the springs, and then maybe $250 in labor. I have a new steel cam gear that came with my MSD distrib but after re-evaluating it, I do not consider this a cost effective way to gain 15 hp.

 

[D.Hearne]

Using Crane's lifters: $150 for the cam, $120 for springs & retainers, $30 for pushrods, $420 for the lifters, $45 for the cam gear, thats $735. Using a reduced base cam, $300 ( guessing here) for the cam, $30 for pushrods, $180 ( for a better set of Crane stock type replacement lifters) the tie down hardware?, $30 at most. $45 for the dist. gear. That's $585, almost $600. Not really worth it in my opinion. If you're starting with a roller block, the costs come way down and well worth it then.

 

[10secgoal]

Pish posh. What about spider plate, dog bones, and push rods from junk yard..30 bucks Cam, steel gear, and springs...dirt cheap, you'd have to weld in the spider plate, but we'll worry about the removal later. Anyone ?

 

[65ShelbyClone]

you'd have to weld in the spider plate, but we'll worry about the removal later.

You're kidding, right?

 

[65fastback2+2]

Pish posh. What about spider plate, dog bones, and push rods from junk yard..30 bucks Cam, steel gear, and springs...dirt cheap, you'd have to weld in the spider plate, but we'll worry about the removal later. Anyone ?

you can drill the two screw holes in the block yourself. cheap, easy.

 

[10secgoal]

You're kidding, right?

Hehe
, yeah of course, but fastback is right. Just had to be careful not to go too far and go into the cam bearings.