Roller vs. Flat tappet cams descussion

[Takid455]

With the new more ‘streetable’ roller cams available of Pontiacs nowadays, I am investigating/ entertaining the thought to install one in my engine. Right now I am weighing the pros and cons of roller vs. flat tappet cams. So far this is what I have found out:
Roller
Broader and flatter torque curve which ‘comes in’ at a lower rpm than tappet
Less friction therefore frees up valve train power
Can reuse lifters with different cams as with tappet it is best to match lifters w/ cams
Cost 2.5-3 times as much than tappet

Tappet
Low cost
Peaky torque curve
Grinds are similar to rollers to a certain degree (lifts, duration)
Proven them selves over time in milestone engines of yesterday

I would like some thoughts to add to this topic. As of now I am limiting the lifters to hydraulic. If mechanical has better advantages, I may consider them and feel free to add your thoughts. Keep in mind that the application / car usage will be street and road racing as opposed to single purpose drag.

[trackrat79]

From all the info out there, you can't beat a solid roller. The catch is that you will probly end up adding valve jobs to you reagularly scedualed maintinance. heres how I understand the differances.

Solid roller. more radical profile, softer valve spring, will last longer with proper maintinance.

Hydrolic roller: can't go as radical with profile, stiffer springs to avoid float, shorter life span. Less maintinance over the life of the cam, just have to replace springs sooner.

[Zee]

With a roller, you won't face the cam wear issues common with flat tappet cams and modern low zinc oils. I believe comp's 288HR is the hot set up for most 455 applications. Crane's cams use press on iron distributor drive gears so you can any distributor gear. You will need a composite or bronze gear with any other manufacturer. At higher lifts, a lifter bore brace is recommended with factory Pontiac and non SD blocks

I'm on a budget so in went my Crower 60310 solid lifter cam and their lifters with the restrictors built in. I like it and there is nothing peaky about the power curve. I don't feel a roller provides a cost effective improvement (performance wise) over a healthy solid cam on a traditional Pontiac with either stock to moderately ported heads. That being said, if for some reason, I loose this cam, it will be replaced by a roller.

[PT Goat]

I went with a hydraulic roller on the advice of my engine builder and I couldn't be happier. Biggest difference I noticed over my flat-tappet Pontiac motors is how quick it revs. I also wanted piece-of-mind with all of the recent flat-tappet cam failures. Mine is a custom-grind from Comp that Spotts has used with repeated success in PT-type builds where AC might be involved. I can look up the specs for you if you want.

[Takid455]

if you woul dbe so kind to list the specs , i would appriciate it.

[critter]

I think you may have your spring pressures reversed regarding roller profiles. I think the solid roller requires the more radical spring pressure since it does not have the cushioning effect of the hydraulic roller lifter. It needs more spring pressure to control the valve action.

FYI, I'm running a solid flat tappet and it's fine for the street but a comparable hydraulic roller gives more average torque under the curve. I'm switching to a milder, HR cam this winter.

[PT Goat]

if you woul dbe so kind to list the specs , i would appriciate it.

Here you go: 230int/236exh at .050 lift, 281/287 advertised duration, and .510int/.520exh lift with 1.5 rockers. Lobe separation is 110. Lobe lift is .340int/.347exh.

[CarlC]

Economics and engine requirements can help guide you on this.

If you can afford a HR and your maximum engine RPM will be below 5800 - 6000 RPM, then it's the way to go. HR's don't like higher engine RPM unless some trickery is done, and that will increase the overall cost significantly. For an average PT build that will see the track occsionally, a HR is ideal. On the next engine I'll look real hard at adapting later model (LT1) GM HR lifters to an earlier block. There was a story recently in one of the mags about this conversion.

If you need to go over 6000 then either a solid or hydraulic flat tappet cam can be used reliably. The current version of Shell Rotella is high in zinc content, or a bottle of GM EOS can be added to periodic oil changes.

For me, solid roller is not an option for a street car. The spring pressures and reliabilty problems surrounding them make it a no-go for me. Reliability is key for me.

[pitts64]

Ta, I run the Crower 60919 (041) with Rhoads lifters in my 462.
It's a wonderful street cam.
I have a 64 Bonneville with a no slip 4 speed Hydro transmission.
The hydro / 2.56 posi combo requires power for 1000-1200 rpm low end cruising. This cam lifter combo along with 10-30 Mobil 1 / GM EOS additive works great.

[Madspeed]

I couldnt help but to add my 2C
A roller cam makes more power because it opens the vavles VERY fast off the seat and closes them very fast as well and slowes down just before they hit the seats.

You can not do this with a flat tappet cam because the ramp of the cam lobe causes the lifter to scrap off the lubrication...

There are gains of up to and over 100 hp with roller cams vs flat tappet with no loss in engine efficiency... that means more mpg for the increased power.

I dont run anything but rollers anymore..
hell my 72 4X4 blazer has a 454 with a Solid roller in it