Lunati Solid Roller Cam

[EffinDuff]

Wanted to see if anyone had any experience with the Lunati Voodoo Solid Roller Cams.  Not too sure if one of their precut grinds would work or if i should get a custom somewhere.  No matter how much i read i can never fully grasp the cam combination or the torque converter choice.     I understand the concept but can never really tell when it will work good for the car.  I do understand their will be maintenance involved with this style of cam and that is not a problem.

Looking to put it in a 440- 512 Stroker from 440 Source w/ their Alum heads.  I believe it was 11.3:1 compression, but he said we can cheat to 11.1:1 with a thicker head gasket.  Not fully decided on gearing and trans but for now my thoughts are 3.55 in the 8 3/4 rear with the tci 727 streetfighter we already have in it.  Had thoughts of doing the Tremek 5 speed conversion but still undecided.

the 72 charger its going in will be used for street / strip.  I will not be killing the car just taking it to the track now and then to enjoy the power.  I know a lot of people will say the compression is high, the guy from 440 source said it would be manageable and I dont mind mixing gas if needed.  I have also read you can cheat a little with the timing if needed.  Thanks in advance for everyones input.  All thoughts are welcome... Be Gentle... ha

[Challenger340]

What kind of Roller ?

"Street" mech. Roller, or more aggressive profile ?

[EffinDuff]

I was hoping for something in the middle.  If anything closer to street.  Probably one of the most important things which i left out is it needs to create enough vacuum for power brakes at idle or low rpm.  I heard this can be a problem with aggressive cams.

[oldschool]

all things being equal,a roller cam makes more vaccum than other cams. i have a solid roller in 2 500" motors  274/276 @.050,they both have power disc brakes with no problem.  i use to run a smaller flat tappet cam, and the power brakes did not work.

[EffinDuff]

Thats a good thing to know.  Who makes your cam, lifters and rockers?  How do you like it and do you have any cons that come to mind?

[oldschool]

Thats a good thing to know.  Who makes your cam, lifters and rockers?  How do you like it and do you have any cons that come to mind?

i use comp cams for my cam and lifters.the rockers are indys 1.6,s. i have roller cams in all of my motors,so yes i like them. large cubic inch motors really respond well to big roller cams.
cons: costly, more to mantain ( tough on valve springs, lifters need rebuilding)
my valve springs only last about 3-4 thousand miles.
i rebuild my lifters about every 3 years or so.

hope this helps

[375instroke]

Is there a long term roller solution?  I like adjusting valves, but replacing springs every 3000 miles...  Are OEM rollers just really small?  Do the smaller rollers last longer?  Is there a difference between hydraulic and mechanical rollers in longevity of parts?

[EffinDuff]

I'm obviously no expert but I would imagine that its the same or similar to the relationship between hydraulic and solid cams. the hydraulic lifter can absorb a lot more then the solid.  The solid exerts much more force to the valves and therefor puts more stress on them wearing them out faster.

I would imagine auto mfgs are using hydraulic roller cams.

Just a guess I'm sure someone will yell at me haha

[EffinDuff]

If I'm not mistaken the Solid Roller has a much more aggressive lobe ramp profile too.

[375instroke]

I still have the original solid cam in my '64, so there's got to be something more to it than that.  Hydraulics don't compress, and the valves are opening and closing very fast, so leakage can't be that big of a deal.  I thought the problem with hydraulic cams is that at high RPM, air may get in them, or the oil pressure starts pumping them up, letting the valves hang open a tiny bit.  Is this true?

[oldschool]

Is there a long term roller solution?  I like adjusting valves, but replacing springs every 3000 miles...  Are OEM rollers just really small?  Do the smaller rollers last longer?  Is there a difference between hydraulic and mechanical rollers in longevity of parts?

i was using mine as an example.my seat preasure is 230#,and 628# on the nose.that much spring wears things out. after about 2-3 thousand miles MY springs lose about 40-50 pounds of preasure. then it causes valve float,and i break valves.
if you use a smaller cam you dont need that much spring and parts will last a lot longer.mine are race springs that i use on the street,so they wear out alot faster.i dont know about hydraulic rollers,as i have never used one.

[oldschool]

I still have the original solid cam in my '64, so there's got to be something more to it than that.  Hydraulics don't compress, and the valves are opening and closing very fast, so leakage can't be that big of a deal.  I thought the problem with hydraulic cams is that at high RPM, air may get in them, or the oil pressure starts pumping them up, letting the valves hang open a tiny bit.  Is this true?

that is exactly what happens

[EffinDuff]

I know I've read that high rpm is a problem with hydraulic roller and I also read that with a solid roller you will get more HP and torque throughout the entire rpm range. As far as why I have no idea I was just guessing with my last reply.

I don't know if the springs wear as fast with the hydraulic roller either.

[firefighter3931]

Hyd roller cams require less spring pressure to keep the valvetrain stable so yes, they do last much longer between service intervals. Stock roller cams found in today's passenger car engines are very mild....nothing like a performance grind solid/hydraulic roller from the aftermarket. 

If you want to run a roller you have to be prepared to stay on top of things. Solid rollers require extra attention and monitoring but to some the benefits outweigh the pitfalls. It just depends on how much power you are chasing and how badly you want or need it.

Comparatively speaking, the solid roller will make more power asssuming similar specs. The hyd lifter design can only support so much pressure before it begins to collapse so the user is limited by the design limitations of the lifter...in this case hyd roller. The lower spring requirements means the lobe profiles themselves cannot be as agressive as a solid roller design. Most hyd roller cams run 175lbs or less on the seat and 450lbs or less over the nose. Typical hyd roller pressures are 150/400 lbs

A "mild" solid street/endurance grind roller will need 200+ on the seat and 500+ over the nose and many more agressive grinds require additional pressure to prevent valve float and breakage. 


As the pressure is increased so must the quality of the parts. You can't run a Crane Gold rocker for any length of time with a 500+ lb spring and expect it to survive. Solid roller cam means expensive rocker arms (harland sharp/T&D) so that has to be factored into the total cost as well



Ron

[EffinDuff]

Thanks oldschool and 375 for clarifying... i didnt see your posts on my blackberry so i just kept rambling on like an idiot.   

i was using mine as an example.my seat preasure is 230#,and 628# on the nose.that much spring wears things out. after about 2-3 thousand miles MY springs lose about 40-50 pounds of preasure. then it causes valve float,and i break valves.
if you use a smaller cam you dont need that much spring and parts will last a lot longer.mine are race springs that i use on the street,so they wear out alot faster.i dont know about hydraulic rollers,as i have never used one.

Do you feel a big enough change in the motor that you can preventatively change the springs and not break valves all the time?  If you were to use a different spring would they last longer or would the sacrifice be too much that its not worth it?

[EffinDuff]

Awesome explanation Ron.  What would you consider to be a good balance (grind wise for solid roller) between longer life and aggressive? 

While you guys are teaching me I am also a little fuzzy on Torque Converters  .  Based on what I've read which is pretty much all race application, is you want to match the torque converters stall speed with your motor so that your motor is putting out the most power at the time it releases (all with trans lock).  How do you figure what is the best converter for a street application.  Same calculations or you looking for a lower rpm stall speed for street?

[firefighter3931]

Awesome explanation Ron.  What would you consider to be a good balance (grind wise for solid roller) between longer life and aggressive? 

You're welcome....hopefully it helped you undertand. 

The right cam really depends on the application. For example : a stroker build with standard port heads (Stealth/edelbrock rpm) will be port limited and stop making power in the 6000rpm range. In that case you can get by with a hyd roller profile because the motor will stop making power before the valvetrain goes into float. A street solid roller is also a good choice because the lobe profile is relatively mild and will be easy on parts (lower spring pressure requirements)

So, it really depends on the build and specificly what the cylinder head flow will support in terms of power given the displacement they are sitting on top of.    On your type of build a solid street roller would be a good choice....nice balance between power and long term durability. The big displacement and modest cylinder head will benefit from the street roller profile....moreso than on a smaller displacement build. 

While you guys are teaching me I am also a little fuzzy on Torque Converters  .  Based on what I've read which is pretty much all race application, is you want to match the torque converters stall speed with your motor so that your motor is putting out the most power at the time it releases (all with trans lock).  How do you figure what is the best converter for a street application.  Same calculations or you looking for a lower rpm stall speed for street?

Tq converters are a completely different subject but certainly relevant when selecting a cam profile. Basicly you want to match the engine power curve to the converters flash stall speed. No point in running a stock 2000 converter if the engine combination you've designed doesn't start making power to 3000. That will just make for a dog off the line and leave you disappointed. 

Cam selection, stall speed and rear end gearing all work together....they need to be matched up. Good street/strip converters act similar to a stock converter during normal driving conditions but will stall higher when you drop the hammer. It pays to buy a descent quality piece in this instance.



Ron

[EffinDuff]

Sweet.  It's all making sense now.    Now to just pick what grind and who to get it from   

If I go with the solid roller i will definately need the better set of roller rockers like you said before?

Solid roller cam means expensive rocker arms (harland sharp/T&D) so that has to be factored into the total cost as well

Out of curiosity where are you a firefighter?  I'm a volly in Thornwood NY, just north of the city.

[firefighter3931]

Sweet.  It's all making sense now.    Now to just pick what grind and who to get it from   

If I go with the solid roller i will definately need the better set of roller rockers like you said before?

I would look at the Comp Cams extreme energy street rollers. The right profile for yours will depend on the factors discussed earlier....stall speed, gearing, displacement, head flow etc...


On any roller cam combination i would spend the money and buy a top shelf rocker arm. Once you break one of the lower priced pieces you will have to upgrade anyway so why spend money twice. 

Out of curiosity where are you a firefighter? I'm a volly in Thornwood NY, just north of the city.

Cool....we have another smoke eater on board.  I'm a full timer in Ottawa, Ontario, Canada....about 8hrs northwest of the big apple. We're 45 minutes from the US border at Ogdensburg, NY




Ron

[oldschool]

Thanks oldschool and 375 for clarifying... i didnt see your posts on my blackberry so i just kept rambling on like an idiot.   

i was using mine as an example.my seat preasure is 230#,and 628# on the nose.that much spring wears things out. after about 2-3 thousand miles MY springs lose about 40-50 pounds of preasure. then it causes valve float,and i break valves.
if you use a smaller cam you dont need that much spring and parts will last a lot longer.mine are race springs that i use on the street,so they wear out alot faster.i dont know about hydraulic rollers,as i have never used one.

Do you feel a big enough change in the motor that you can preventatively change the springs and not break valves all the time?  If you were to use a different spring would they last longer or would the sacrifice be too much that its not worth it?

i just change them after about 2000 miles,just to be safe.i let the springs go too long this year and had valve float that broke a exhaust valve.
you have to use the right spring for the cam. not using enough spring,i would have the same problem. to much spring is not good either,it would just wear things out faster.the right spring is strong enough to allow the valvetrain to follow the profile of the cam lobes,but not so strong as to not cause excessive wear.its a pretty fine line.

[EffinDuff]

When you broke the valve did it cause any damage to the guide or was it just swap and fit the valve?

[oldschool]

the head of the valve broke in half,so the rest stayed in place.it spit the broke piece out the exhaust. it only put some nicks on the top of the piston and on the head. i was lucky. i bought all new valves and springs,the guides were ok.

[375instroke]

So what's a good non-aluminum rocker?

[Purple440]

While you guys are teaching me I am also a little fuzzy on Torque Converters  . 

Hey EffinDuff - Ron helped me out big time with determining that lack of stall speed was one of the main reasons my take-off performance sucked.  My cam power range is 2500-6000 but my stock converter stalled to 1800rpm.  After talking with Ron and the other pro's around here, I got a converter that stalls around 2800-3000rpm and man what a difference.  The main tip I got was make sure your stall speed is "into" your power range, not before or at the beginning of it.  So I'm about 300-500rpm into my cam power range before she hooks 100%.  But still great street manners, no slipping at low speeds (not much anyway) with my A&A converter.

Good luck with yours 

edit: I WISH I would have gotten a converter with a stall around 3500rpm instead, but too late.   So...when it doubt, whip it out, as my old drill sergeant used to say.

- Doug

[oldschool]

So what's a good non-aluminum rocker?

if you are not running too much cam or spring,its hard to beat the nodular iron max wedge rockers