I have been told by 2 people now that unless I go with at least .600 inch lift and LOTS of duration it is not worth going to an roller cam setup. I have an th350 auto trans with stock converter so I dont wiant to run a huge cam like that. I have a dyno program and the Comp Cams Hydraulic Roller 270HR seem to make way more torque across the whole powerband and seem like a real nice cam. It would be used with Sportsman II headers, full length headders, wiend duel plane intake, and still need to get a nicer carb. Is the roller worth it or should I just get something like a Comp Cams Extreme Energy 268 with some rhoads variable lift and duration lifters(blead down). Thanks for your input. Oh ya, specs on 270 roller are LIFT :.495 int .500 exh DURATION 219 int 224 exh

 

I personally love hydraulic rollers. You have several advantages: Much longer life. No break in. Lower oil temp (lower friction). Faster ramps = more power & torque for a given 050 duration. All vehicles from the late 80's and up have roller cams. There has to be a reason for that.

I have a custom ground hydraulic roller in my 454 and it works great.

 

There are a number of other reasons why a roller is benificial :

1. Reduced friction. Becuuse the roller bearing contacts the cam lobe and not the dished surface of the lifter body you are generating less friction, less heat, reduced wear and longer oil life.
2. Less overlap. When running a larger flat tappet camshaft there is a limited amount of ramp that you can subject the lifter to. Thus with larger camshafts there is a longer ramp to the point when the valve is fully open, thus more overlap. With a roller cam you can literally slam the valves open and shut as the roller bearing is much less sensative to lobe ramp up angles. This can allow a motor to run more duration with less overlap, giving a car more low end.
3. Longevity. There is no break in period, and the chances of a cam going flat are almost nill with a roller. Look at all the OEM, they all exclusivley run with roller camshafts. The crate motots, ZZ4 etc are all running roller cams.

I have a roller in my car and I think its performance exceeds that of a flat tappet cam.

 

I wouldn't leave home without one. The cost of going roller is about $1200. You would have to understand cam science to understand all of the benifits. If you run the same cam specs with all four types of cams the solid roller would have the highest intake vacuum the smoothest idle and the most HP. But it only marginally beats out the hydro -roller.

Hp cost money!

 

here is the dyno comparison. Does it look acurate? If so it definently seems worth it. But I have had people tell me that they are really not worth it unless you run a real BIG. Damn! How do you attach images?

 

Be careful of you Dyno program. Only use the roller option if you are using a radical mechanical roller cam. In fact, Dyno 2000 tells you to use the regular hydraulic flat tappet setting unless you are using a radical roller cam. Otherwise it WAY over estimates the HP. Hydraulic rollers and flat tappets of the same duration and lift do NOT have significant HP differences. The only differance is, the roller will ALLOW you to run a higher lift and duration while maintiaining streetable idle characteristics. i.e. a 284 with .510 lift flat tappet cam may be unstreetable in a 350, but you may be able to run the roller version of it on a 350 because of the steeper ramps and less overlap.

PS for what your considering, I don't know that I think it's worth it from a cost vs benefit view. If the flat tappet version of the cam (same lift and duration) is streetable, then I say keep your money in your pocket and get the flat tappet version. You won't gain any significant HP with the Roller, and they are both prone to valve float over 6,000 RPM's



[Modified by 79MakoL82, 11:20 AM 3/22/2002]

 

I love my hydraulic roller. For a hot rodder it's a touch decision for going between a solid roller and a hydraulic roller. The solid roller profiles make me drool with their nice lift numbers, but any cam manufacturer will tell you they are not good for street use and require periodic maintainence (setting lash and inspecting lifters). There are some scary stories of solid roller lifter failure, which can lead to big engine damage (valves hitting pistons). Another advantage of the solid rollers is their increased rpm potential over hydraulic rollers due to their lighter lifter weight. If you want to rev over 6500 or so, you'd want to give serious thought to a solid roller.

One thing about the nature of roller cams is that the initial ramp is very slow, then speeds up quickly. So if you look at the duration between .005 lift and .050 lift, it is longer than a flat tappet cam, however, between .50 open & close you get a lot more lift than with a flat tappet cam. The difference is dramatic when you get into beefy cams. For a short duration cam (210 @ .050 ish), there is not a very dramatic difference between roller & flat tappet.

If I were on a budget, I'd consider a couple alternatives. One is hydraulic flat tappet fast bleed lifters like Rhoads lifters. They have the effect of shortening the duration of a cam at low RPM (VTEC for rednecks :) ) I've heard a lot of very positive comments about these, but you have to do your research and size your cam correctly and install it correctly (cam timing is important with these because they cut duration off the end the ramp, effectively advancing the cam at low RPMs).

Another thing I would consider is getting the lifter bores increased to use a Ford or AMC style lifter with a custom ground cam. They have larger diameters, which allows for cams with much faster profiles. You can get chevy hydraulic roller profiles with flat tappets. I'd get an experienced machine shop to make sure your block has enough meat by the lifter bores to handle it though.

Rob

 

WOW :eek: I took the roller option and set it to hydraulic flat tappet and what a difference! It makes more power but not much! So when you start running BIG lift LOTS of duration and MUCHO rmp that is where the program becomes more accurate? I understand all the benifits of a roller cam and agree there better but I guess I would like to see some accurate #'s in power increases so I decide if the $$$ spent would be worth it. With roller option turned on seems worth it. Came cam with roller option changed to flat tapped it does not seem worth the dough. At least for my setup that is.

 

Believe me. This is more accurate. Again, same duration and lift will equal similar HP. The roller will ALLOW you to run a more radical cam with higher lift and duration because of less overlap. That's the real benefit. So unless you are going to use the roller to go to a more radical cam, keep your money in your pocket.

That's my opinion anyway. The views of others in regards to the benefits are all valid. I would just prefer to spend my money on other mods.


[Modified by 79MakoL82, 11:29 AM 3/22/2002]

 

Finally caught up with the rest of the posts. Thanks for all the great info :D I will probably go with the Rhoads lifters and flat tappet cam. Any suggestion on a good cam. Probably wont boar the lifter boars because I dont want to strip down the moter and send it in. It is already assymbled and in the car. I am just going to swap out the heads and cam. I am running crappy stock casting heads and a pretty wimpy cam. Going to pick me up a set of dim der Sportsman II heads Cant wait! :D

 

I once had a hydraulic (non-roller) cam and Rhoads lifters.

I now run a solid roller. More expensive. Definitely more torque and power with slightly better vacuum/idle. Awesome driveability.

The previous cam (that I ran with Rhoads lifters) was a Lunati with 280 off the seat, 232 @ 0.050", 0.475 lift, 110 degrees lobe separation, as I recall.

Here are my current specs. I am far, FAR more pleased with the way this roller cam runs.



-Noel

 

I bought the ZZ4 because of the roller. Cams of the same duration and lift make the same power. No difference between roller and non roller

The advantage is that you can run high lift with short duration giving great power without hurting driveability. ZZ4 makes great numbers but idles great with good gas mileage.

 

Yep! :yesnod: :yesnod: :yesnod:

 

Okay guys, we have the positives here. Any negatives?

$1200 - what is the huge cost for? CAM, special lifters,
different springs? anything else? Block machining? I though there were
special lifters that didn't need machining...

 

Well, one cost from the Crane site is the $528 cost just for the retrofit roller lifters :eek: . These are the ones that do not require machining to your block.

AC


[Modified by A C, 6:56 PM 3/22/2002]

 

I did the complete setup for $650. Included the cam, retrofit lifters, shorter pushrods, cam-lock plate and thrust bearing. Got it from internet racers supply. All parts are comp cams.

 

I am using the cam you mention. My engine is similar, TFS heads, 1.6 RRs, Air gap rpm, Demon 750. I have an M21 w/3:55 gears. You might want to go one cam smaller w/stock converter. I spoke to Comp Cam tech guy. He picked the 270 because of my gears and trans. I am extreamly happy w/engine. Powerband is SEAMLESS! Get a retrofit kit and save big money.

 

There's alot of good info here. If you want a very detailed analysis of cams, including hydraulic rollers, check out the latest issue of Chevy High Performance. Very informative.

 

Okay guys, we have the positives here. Any negatives?
$1200 - what is the huge cost for? CAM, special lifters,
different springs? anything else? Block machining? I though there were
special lifters that didn't need machining...

I just jumped through the Jegs cat. just to price out a conversion. Your going to need a button type cover and good cam timing and chain $200. Cam $250 or so. $260-360 for roller lifters. good pushrods $120 Springs, locks and retainers $250 minimum, Screw in studs and guide plates ????? roller rockers $$$$ Stud girdle with custom Allen locking nuts???? bigger valve covers. All the new conections for PVC and breathers. Gaskets....... It never ends. I have nice stuff . But I didn't go shaft rockers. You have to cut cost somewhere. I did go rev kit and titanium intakes valves with titanium retainers billet small circle base custom cam and it's more like $2000+

It's well worth it. If your not feint hearted! The biggest bang for the buck is high flowing heads with lots of compression and then see if you need a max cam.

 

What's the cam size in a ZZ4?

Thanks!!