how possible is it to get a solid roller to idle smoothly, quitetly? Will it give increased rpm capability with small cams as well? i figure increasing the rpms wont hurt the solid lifters like hydr's would, so power would stay high beyond hydr.cam capabilities. For an LT4 say a cam with 224-234 duration and .580 lift... what is the rpm range for it, will it make power beyond 7k?

 

The mechanical rollers I looked at from Comp Cams all tap out at 7000 RPM and you need more duration ( 250 to 260 ) to get to 7000 RPM. They do make 8000+RPM cams but would be no good on the street.

There are many other manufacturers out there as I was only looking at one, but those RPM's generally make the power band of the cam too high for street ( 3500 - 7500 RPM ), but great at the track .

 

I'm running CompCam's XR274 in a 362 ci engine. It's got 236/242 duration
at .050, .570 lift and 110LSA. Their advertised power band is 2200 to 6200,
which a nice pretty wide range.

One of the reasons I chose it is because the
valve lash is relatively tight at .016 and .018. You can hear the valve train but
I wouldn't call it noisy or thrashy. I've got long tube headers (with some
relatively quiet mufflers) and the headers make as much if not more
noise than the valve train.

With a 30lb flywheel and some ign advance at idle, it shakes a little
at 850 to 900rpms, but not bad. When I retard the timing and lean out
the idle mixture at idle, it can get pretty rough. CompCams makes "one
size smaller" XR solid roller, and if I want something a little tamer but want
to keep a solid roller I'll either move down to that and/or have one ground
on 112 LSA to reduce the overlap.

At first I had a 16lb flywheel, and getting moving from a stop was not very
good. It was doable, but not as easy as I want a street driver to be. The 30lb
flywheel made a significant differenece in keeping the rpms from dropping
off fast and made starts much smoother, which makes for in my opinion a
more "streetable" driver.

Don't know if that helps you any or not. One thing to keep in mind is that
one persons idea of smooth, tame or "streetable" is not the same as
another's.

The absolutely best way to make something smooth, quiet and make lots
of top end power is to turbocharge it.

Dan

 

By their nature, a hydraulic lifter has a lower maximum rpm ceiling than a solid. The rpm range of the power band, however, is a function of the lift and duration of the cam, not to mention the way the rest of the engine is cofigured. I can't picture a reputable cam grinder marketing a cam that is meant to produce power in an rpm range beyond the capabilities of the lifters it recommends for it's cam. I have a CRANE roller hydraulic cam (yet to be installed) that states on the cam card, "Recommended RPM range with matching components: Minimum RPM: 3500; Maximum RPM: 7000; Valve float: 7500". I "trust" that Crane, as a reputable cam grinder, has done their homework, and that this cam WILL produce to 7000 RPMs. This cam card makes NO representation as to idle quality, and I am expecting the worst. Almost without exception, higher rpm horsepower comes at the expense of lower rpm torque and idle quality.

There ARE street oriented solid roller cams that will idle reasonably well, but they aren't likely to produce the BIG numbers at 7000 rpms. For a cam that idles well, lifter type (solid vs hyd.) is a moot arguement as to rpm capability. Just as a roller cam can have quicker acceleration rates than a flat tappet, a solid can, similarly, have quicker rates than a hydraulic. The solid roller will likely offer better power for a given idle quality than a hydraulic. The trade off being the noise and necessity for periodic adjustments. Good luck, and...

RACE ON!!!

 

What im basically looking for is a cam that will make peak power around 66-6800 rpm, i wanted a redline of 7500 (shift point). Im hoping that the cam will make a sort of flat power curve beyond 6800 not losing too much off the peak. That sound possible?

 

I've been using Comps line of Xtreme Energy Street Roller (mech) cam lobes. They're designed to run on the street, so the recommended lash is pretty tight, .016"/.018", and the ramps, while more intense than a hyd. roller, are easy on the valvetrain and don't beat it up. I selected lobes from this line on one of the cams I dyno tested in the NA SBC 427 and it made nearly as much power and torque as the drag race-oriented High-torque .406" lobes, that Comp described as "very aggressive".

These lobes are very capable of producing big power, and both cams I've used these lobes on, the current 254/254, 115LSA and a previous 256/264, 112LSA cam, had very good idel in the 850-900 rpm range and pulled between 9"-11" of vacuum at idle.

Each peaked in hp at around 6600-6800 rpm, and peak torque around 5100 rpm, but each still made good torque down low. The 256/264 cam helped make 500+ ft lbs from 3000-7000 rpm, with over 400 ft lbs at 2000 rpm. That was with 11.3 compression. We spun the engine up to 7500 rpm, and although it had passed the hp peak and was starting to decline it was still over 600hp.

 

First, I agree with Monty. How big of an LT-4 are you talking about? The cam you have outlined above, will have a good idle and street manners in a stock displacement engine. It will calm down even more, with more displacement. The cam you discribe will not pull the "big" numbers at 7000 rpms. Look at the durations Monty is citing. These are MUCH bigger cams.

A lot of the answer depends on your interpetation of "smoothly" and "quietly". It is MY interpetation, that Monty is more forgiving of a "healthy" idle, than you may be. This is not a critism of either of you, just an observation made by "reading between the lines".

Not in MY opinion. What will the usage for this car be? What can you tolerate? Good luck, and...

RACE ON!!!

 

Sorry to change the subject here, but Monty, what lifters are you running?
I too am using Comps Xtreme Energy solid roller, and I got their
"recommended" lifters which are the Endure-X lifters, even though they
were nearly twice the price, and now I'm seeing posts about problems
with them. So just curious what you are running.

Thanks,
Dan

 

Well its a 383 bored .060, = 387 ci (388). The heads have 2.055 intake and 1.6 exhaust valves, heads flow 314 @ .550 lift. They are hand massaged by a secret tuner. anyhow, a camaro they did with a baby smooth idle put out 419 rwhp in a 383 with a similar combo. The hydraulic roller motor pulled higher right up till fuel cutoff at 6750 (what he set it at) My headers are better, exhaust better, intake is better, heads flow more better, cam lift is greater, duration is more agressive etc.. im also going to run a DFi since the stock pcm wont go beyond 7k without shutting off. I was hoping to get nearly 450-460 rwhp out of it. The builder says it will be beyond that. This is basically a pushrod LT5 clone. My old Zr1 revved nicely, and i hate the 'out of breath' feeling my lt4 gave me at only 6 k rpm. heres some details...
95 Z28 / Vs My LT4
383 / 388
scat crank / Callies Crank
eagle rods (6.inch rod) / oliver rods (5.85)
je pistons (11:1 comp) / Je forged lightweight (11.5:1 comp)
lt4 heads, 2.02, 1.56 valve (298 cfm) / LT4 heads 2.55, 1.6 valves (314 cfm)
52mm TB / 58mm Holley with SLP triflow intake
Shorty headers / TPIs w/o emissions, coated longtubes
Stock Hydraulic lifters / Solid roller setup
Crane 1.6 rrs / Crower 1.6
single 4 inch exhaust with cats / B&B 3 inch no cats
stock wp / Mezziere pump
stock / MSD ignition
stock/ 4.09 gear ( :) )
obd1 / Accel DFI

probably lotsa little stuff i cant remember. anyhow, since it was based on a mild setup that works, we're really excited to see what this combo will do. The cam deal is what bothers me. id like this motor to really boogey around 6800 rpm, and maybe shift it at just over 7. Im starting to do away with the smooth idle mumbo jumbo. THe next time im up against my friends Viper GTS i aint gonna care how my car idles! :cool:

what doyou guys think.


[Modified by FRC2000, 5:09 AM 1/28/2003]


[Modified by FRC2000, 5:11 AM 1/28/2003]

 

quote "We spun the engine up to 7500 rpm, and although it had passed the hp peak and was starting to decline it was still over 600hp.
_______" end quote.

What im trying to say is based on my stock LT4. It made peak at around 5800 but i hang it out till 6300 anyways. It was obviously making less at 6300 but it still pulled good.

Oh and this is mainly a highway missile. :D


[Modified by FRC2000, 5:07 AM 1/28/2003]

 

It sounds like the new set up will be quicker than the old. Personally, I think you can use more cam than you origionally outlined. I would listen to Monty, here. I think his engines have been larger then these, but *I* would seek and value his advice. Good luck, and...

RACE ON!!!

 

Jesel .875" tie-bar solid rollers.

 

Some really good lifters for a street motor with a solid cam are the new Red Zone maximum endurance lifters by Isky. http://www.iskycams.com

That is what I went with for my new big block. Pricey(about $500), but they are supposed to be the best endurance lifter out there.

 

Hi Guys,
A off question on the same subject. I was looking to do a SOLID ROLLER
for the street, a reasonable profile, and I was told that the lifters will only last at best 5000 miles. At every 5K they suggest intake removal and to take a peak to see if everything is good. How many miles have you guys put on these setups?
Lou

 

I have run standard Crane solid roller lifters for 25,000+ miles and they still looked fine.
Much of this will come down to spring pressures though. I was usually able to keep spring pressure down with light components. My small block was running under 200lbs on the seat and about 500 flat over the nose and spun to 7200.
If you raise spring pressure you will shorten lifter life span. With some of the better lifters will hold up better. Those Isky lifters have additional oiling to the roller to help roller bearing life span. Oddly enough, one of the hardest things on high load lifters is low RPM and idling as the rollers do not get much oiling.

 

Thanks for the reply Phil. Wondering what cam # you are using? I'd like to see if the specs are simular to what I am looking for. Great to hear I might be able to do this after all. I'm using Trick Flow heads with the lesser springs. Might have to change them. I'm not looking to go crazy, but I think they are only good to 0.510 lift.
Thanks, Lou

 

I've got a Comp Cams XR274 with the Endure-X lifters. So far, I've put 16k miles on them. I'm running 150/420 spring pressures and I'm not concerned about a failure, but I'll probably pull the intake sometime this month (need to check for oil leak problem) and I'll inspect them.

I don't think you will find a solid roller with less than .550 lift and they usually like a little more pressure than the hyd lifters so a spring change would be in order.

 

I am using a mild solid roller in my 74 [see sig]. Make sure that the cam is a steel cam and not cast. The cast cams will ware at a much faster rate. I am using Crane vert lifters, have 10,000 miles on them with no problems. I did have a problem with Crane gold rockers, one failed at the trunion. I replaced them with Crowler ss roller rockers. I have 155/450 spring on the heads.
This cam grind is great for the street as it will idle as low as 600 rpm with a nice sound and no lump at idle. It will only pull to 6000 rpm, but I just love solid cams. I also get 17mph with this combo.
Ed

 

FRC2000 - Your heads have impressive flow! I would not even think about stock SR cams. Invest in DD2000 or some other program and run simulations. On dd2000 i could sent you some cam profiles approaching 600 hp with less tha 246 dur intake. You also want to plan on low to mid .600 lift