stealthramman

To you camshaft experts out there, consider this:

What about using a solid roller cam with some milder street specs, so that a guy could:

1. have a decent idling engine with strong vacuum and good emissions

2. use high lift to generate lots of mid range and torque and reasonable mileage

3. have an extended RPM range(beyond 6000rpm) by saving significant valvetrain weight and avoiding hydraulic roller lifter pump up

What do you think? Can solid rollers be made to live with every day street usage? I was told "no" by comp cams techs about a year ago. Has new technology made this possible yet??

MaxRaceSoftware

after 100,000 + miles on Comp Cams 270 HE hyd cam in my Chevy Suburban with 406 cid SBC
2 intake lobes rounded-off recently

that CC cam went about 40,000 miles more than i expected it to
so i'm pretty satisfied...i wish it would have been more though


i already purchased a low-lash (.008") street roller cam from Terry Williams at Cam Motion, Baton Rouge, LA

along with Crower HD pin-oiler roller lifters

i try to use a roller cam in everything we build
never wipe out a lobe

i've had a few solid and hydraulic cams wipe out lobes
even in just a few dyno tests....even though we breakin engine under light load at 1 hour or so...still managed to get a lobe sometimes..its pretty rare , but does occur

as far as performance gain Roller -vs- Solid or Hyd
you have to go at least .500" lift on up for the Roller cam to start showing you big HP advantages

at lower lift the valve lift acceleration rate of solid or hyd is close enough to roller that there isn't a huge performance advantage yet.

stealthramman

The tech dude from cometition cams mentioned that due to a lack of oiling at lower (street) RPM that the solid roller lifters didn't last on the street.


Anyone have a significant amount of reliable street time on a solid roller?? (I don't care about a 'once in a while' lash adjustment, i'm talking about long lasting valvetrain.)

stealthramman

MaxRaceSoftware, using a high lift what i was saying. By using high lift, with a mild/medium (streetable) duration, and eliminating the weight of the hydraulic lifter and associated rpm pump up, in theory you could get a very powerfull street motor.

James

MaxRaceSoftware

stealthramman .. you are exactly correct ! ..but you actually didn't state how much Lift you were using

.450 or .500 Lift to some people is a lot of lift sometimes ?


i try to post conservative .... but "street racers" i do work for in my area running on pump gas ..a few are almost at .750+ Lift
and running 9 to 11 second ET ranges on engines alone

so "street " term is kinda of vague sometimes, hard to really give exact recommendation

stealthramman

MaxRaceSoftware. (talking theoretically here) I was thinking that in a small block you could use a very streetable duration of maybe 215/220* and with a big (net) lift solid roller, of maybe .600". You could have super wide torque and rpm curves without the typical 'fall-off' that a hydraulic would suffer after 6000+- rpm.
Did your cam supplier have any specific recommendations for your replacement solid roller set up?

MaxRaceSoftware

.600" Lift .....yes my Chevy 406 cid daily street Suburban now has .605" lift low-lash solid roller going in it


but you must be carefull here ..... most all SBC heads
"can" take a dive in Flow above .450 lift to .600" lift range
no matter what the flow curve looks like on their website sites
they always show you their best flow curve !

thats why some people try higher ratio rocker arms report gains and some racers report no change or losses

not so much effect or might not happen if you never BACKCUT the intake valve with a 30 degree backcut
..but you don't get a lot of low to mid-lift flow without backcutting the intake valve


so to make everything work out correctly, you have to port the intake short turn radius correctly to work in conjunction with
a 30 deg backcut angle for cams near .600 " lift

otherwise, don't let anyone backcut the intake valve
if you don't have access to FlowBench and headporter

stealthramman

I was almost sold on going Solid Roller, but i read some old posts where guys had problems with them on the street. Kind of make me rethink my plan.

Maybe a custom agressive hydraulic with an R series lifter might do as well on the street?

I want to be able to buzz the motor into the 6,500's and surprise some people with the 'old IROC'.

john35thss

Ran my 383 solid roller supercharged car all summer and cam was never an issue (copper head gaskets). 10000 km lashed once at 5000 236 248 comp cams approx 600 lift and had 14 pounds vac at 900 rpm. changing cam to 224 236 but keeping solid.

rskrause

With cams in the range being discussed here, there is really no benefit to a SR. The more aggressive HR ramps are very comparable to the smaller SR lobes. Why bother with the cost of the conversion and the need to adjust valves if you don't have too? As far as I am concerned, SR setups become necessary only when you start to design a valve train for 7,000+ rpm. If you want a cam with 230-245 or 250 degrees duration @ 0.050" you can get hydraulic lobes with >0.600" lift, and I would not advise anything bigger for street use anyway.

Rich Krause

LT1inaMGB

To me, the advantage of a SR over Hyd would be that you could maintain the shorter duration and reduced overlap for streetability while utilizing steeper ramps and higher lifts for more area under the curve. I would think that combination would provide substantial HP and torque increases in the RPM range defined by the duration you select and maintain 16"+ idle vacuum for drivability. The power would still drop off before 6500 RPM but how many guys need a 7,000+ capability for their daily drivers?

Zero_to_69

I think many people have a difficult time admitting that their "daily driver"
is actually a weekend strip monster.

Reading these points and throwing in what I've been taught, a HR
can be setup and lashed to perform *similar* to a mechanical cam.

Since we're talking about SR vs HR maintenance, why not set a very
conservative preload on the HR...let's say, 0.005" - 0.010".

That will satisfy some of the performance needs, as well as provide
a little time before adjustments are needed.

How long would it take to shave 0.005" off the valve train components
in a full roller setup?

In any case, there are some wild HR cams out there that seem
overkill for street use...so why go SR to begin with (for daily drive)?

My friend (Bob) will set lash after every pass in his top sportsman
Camaro. If things change enough to be setting lash every "seven
seconds" to ensure max performance, is there really a need to have that level of maintenance on a street/strip car?

OldSStroker

I guess I'm saying the HRs do exactly what you want a SR to do for a street engine. That's my kind of street engine also.

SR lobes with 230 or less duration @.050 and 140+ @ .200 and .340+ lobe lift aren't very readily available. HR lobes like this are easier to find.

As Rich said, HR lobes like Comp's 319x series are perfect for what you suggested. I've seen a 3190/3192 (214/224) with .565/.605 lift make upwards of 550 hp on a 365 cube SBC, and idle less than 900 with no lope, and pull from the low 2000s to 6500 peak power. It had negative overlap @ .050. SR lobes like that are rare, but if you want 230-280 @.050 you have a huge choice of SRs.

FWIW, and LT1 in a MGB? My MGB buddy would have a coronary! We're trying to get him to bolt in a T5 transmission. Geesh, 10X the hp would do him in.

stealthramman

AHA! a reply from someone who has actual experience! I'm glad that you replied. It seems that theoretical discussions can go on forever without reaching a conclusion. What actually works in real life and in an engine is what really counts!

The motor you describe sounds wicked, and would be about perfect for my needs (wants?).

Would it be recommended to use a 1.5 rocker, or could a 1.6 (pro magnum) work? Also, if this combination has the ability to rev past 6K RPM, should a different lifter be used such as the Type R? Can you also comment about what would be required in the motor to make that combo work? ie. compression, head flow, etc. ?

OldSStroker

You have mail. Too long to go into here. You are on the right track.