Solid Roller...

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Solid Roller...

Post  Pusstang on June 15th 2012, 9:16 am

I have been reading a lot about Roller failures with solid roller cams... How can there be so many roller failures with so many people that run a solid roller, I have never heard of this failure until reading on these BBF forums...
Most say that the failure is due to excessive idling... But, I have seen hundreds of "racecars" idling in the pits, at the gates, warming up, etc.... can this truly be the issue?
It is also said that the issue comes from poor oiling in the "top-end"
What if you ran Roller Cam bearings, this would raise the pressure/volume in the entire motor...
What do you guys think about this?
The reason I ask is I am building a turbo'd strip/weekend warrior and want to run a solid cam for the ease of use with boost.... Ease of use meaning, slightly higher spring pressures to help control the boost/backpressure pressures and all the ill-effects from trying to run a HR in a BBF...

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Re: Solid Roller...

Post  IDT-572 on June 15th 2012, 9:25 am

Pusstang wrote:I have been reading a lot about Roller failures with solid roller cams... How can there be so many roller failures with so many people that run a solid roller, I have never heard of this failure until reading on these BBF forums...
Most say that the failure is due to excessive idling... But, I have seen hundreds of "racecars" idling in the pits, at the gates, warming up, etc.... can this truly be the issue?
It is also said that the issue comes from poor oiling in the "top-end"
What if you ran Roller Cam bearings, this would raise the pressure/volume in the entire motor...
What do you guys think about this?
The reason I ask is I am building a turbo'd strip/weekend warrior and want to run a solid cam for the ease of use with boost.... Ease of use meaning, slightly higher spring pressures to help control the boost/backpressure pressures and all the ill-effects from trying to run a HR in a BBF...

Idle at low rpm is one also valve float which could be low spring pressure or push rods not up to the task.

I think from what I have seen and done over the years , that roller lifter failure can usually be traced back to a root cause. and it's not the lifters fault.

I have seen Comp lifters live through three different engines and a high end set fail in a half season. And also the other way around.
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Re: Solid Roller...

Post  rmcomprandy on June 15th 2012, 10:26 am

Excessively long idling periods with low oil pressure along with high valve spring loads DO have a detrimental effect upon the bearings in the roller wheels.

How much is "to much" is determined when it fails.

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Excessive Run Time

Post  mkopmani on June 15th 2012, 12:14 pm

I agree with the earlier responses, and would also like to throw in excessive run time with agressive cam profiles combined with a lack of preventative maintenance. One guy I know runs a healthy roller on the street and at the end of the year parks it for the winter without backing off the rockers - meaning that a couple of springs are left in a near full compression state. Not something that I'd do.

Rollers can live, but you have to be vigilant in checking for signs of problems before it's too late. The physics of what's happening have a cost to fatigue life and you have to respect that.

Mike

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Re: Solid Roller...

Post  Pusstang on June 15th 2012, 1:10 pm

I agree... What do y'all think about a cam that is a solid roller with a roundabout spec of .750ish lift and 255-270 duration @ .050, on a 115-120 lsa? How aggressive is this in your minds bc people say aggressive all the time but have no numbers to quantify aggressive... I see aggressive as at least .800+ lift and over 280 duration(280 being on the low side of aggressive!)
And with the cam specs near the above, how would this do with roller cam bearings in addition?

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Re: Solid Roller...

Post  rmcomprandy on June 15th 2012, 1:21 pm

Pusstang wrote:I agree... What do y'all think about a cam that is a solid roller with a roundabout spec of .750ish lift and 255-270 duration @ .050, on a 115-120 lsa? How aggressive is this in your minds bc people say aggressive all the time but have no numbers to quantify aggressive... I see aggressive as at least .800+ lift and over 280 duration(280 being on the low side of aggressive!)
And with the cam specs near the above, how would this do with roller cam bearings in addition?

"AGGRESSIVE" is simply a term given to a combination of acceleration and velocity and usually how much valve spring is needed to control the valve train for a specific lobe profile.

What is considered aggressive for a street engine may be pretty wimpy to an all out race engine.

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Re: Solid Roller...

Post  cool40 on June 15th 2012, 2:03 pm

i just found a lifter before it failed in my BBF.it had'nt hurt anything but you could tell the bearing was rough,crowers with a LOT of run time.i think the reason for most lifter problems is poor valvetrain adjustment.loose rockers will beat the hell out of a lifter and it only takes one time! these crowers i just replaced spent their life on a 800+ lift @ 280+@.050 with 800+psi open on the springs. i have never ran lifter bushings,restrictors to the topend,or roller cam bearings and never broke a lifter in 20yrs BUT that could change next time out.1/8 mile racing is not very hard on parts. Very Happy
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Re: Solid Roller...

Post  Pusstang on June 15th 2012, 2:38 pm

A

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Re: Solid Roller...

Post  466cj on June 15th 2012, 7:17 pm

A "rev" kit can help a lot to extend the life of roller lifters on the street. They should have named it "Lifter saver".

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Re: Solid Roller...

Post  Pusstang on June 15th 2012, 7:26 pm

Who sells this?

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How Big is Too Big?

Post  mkopmani on June 16th 2012, 6:50 am

Pusstang,
How Big is Too Big is really a question of application and the intent for the vehicle. Although it may sound corny, the best way to answer this is to use the cam manufacturer's recommendations as they will only recommend something that they know will live. As you noted that your setup is targeted for street/strip, that means that it will require durability; that you're not talking one or two 10 second blasts between checking lash.

When you look at Comp Cams solid rollers, you'll find that they consider street/strip rollers to be around the 0.650" lift range and not much more. While this may not seem like it's a whole lot different from what can be achieved by solid lifter cams, the area under the curve will still be much greater with the roller. Since you're doing a turbo application, you have the luxury of a pressurized intake which will not require a ton of lift to produce power levels that a street/strip combo can satisfy. I built a 514 for a griend who runs it on the street with a 0.658" solid roller with around 256 @ 0.050 in a '64 Galaxie and it's given him no trouble. I may get criticized by some who may claim to get away with more radical cams on the street, but I'd bet that the run time durability is not there. Wouldn't the cam manufacturers offer a more radical street cam to the market if they could guarantee it would live?

If you want performance, the roller is hands down a better performer over a solid - that debate is over. If you're on a budget or you want to keep it simpler, a solid can satisfy that. If you decide to go solid, I'd have the cam nitrided as the extra hardness will help preserve the cam. Flat tappet cams are all chilled iron which on its own has limited hardness. Also very important with a flat tappet is to break in the cam with only the outer springs, then go back and put the inners in. This allows the cam to lap in and spread load over the lobe. Excessive spring pressure right off the bat will result in oil shear and wipe out the lobe.

On the side of my drag car efforts, I'm doing a 427 High Riser motor for a T-Bolt clone car. The car will similarly see mostly street, occasional strip fun. I'm going with a nice big solid lifter cam from Comp Cams very similar (0.630" 310 advertised) to the C8AX-D FoMoCo hot cam for the 427 (.600, 330 advertised). This engine will put out close to 600hp and should live a healthy life.

Hope that this adds some insight to help you decide which way you want to go.

Mike


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