Author Topic: At what lift would roller rockers start becoming a necessary upgrade  (Read 3262 times)

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Offline gryphon

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At what lift would roller rockers start becoming a necessary upgrade
« on: Sunday, February 15, 2009. 11:01:55 AM. »
I know that with a high lift cam it's a good idea to use roller rockers so that you don't have  the face of the rocker arm constantly rubbing against the top of the valve stem as it opens and closes. I guess this can't hurt anything even on a low lift cam but, at about what point would you have to say that "yes, from this point and up you should use roller rockers". I'm starting a new build and will be using the heads and rocker assembly's from my present S&S motor to complete the new one. Since I'll have pretty much a whole motor just sitting here I figured I'd collect parts to maybe finish the old one off. The cam in it has a .500 lift which is fairly mild by the standards of the day. I would think that standard rocker arms should be just fine. Any opinions. What would be the highest lift before rollers started becoming almost mandatory.

Offline choseneasy

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #1 on: Sunday, February 15, 2009. 11:50:15 AM. »
Just my opinion, but I think rollers are a bit overated. I have run 600 lift(on my intake) with the standard rockers and put 100,000 miles on it and no problems. I doubt there is any "roller" action at higher rpm anyway.

Offline fxr4mikey

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #2 on: Sunday, February 15, 2009. 12:26:56 PM. »
I don't know a 'direct' answer to your question .... but IMO you certainly do not need to consider roller rockers below 560 lift

I''m going with a 510 lift and I'm not putting in rollers .... and I am very confident that I'll not have any problems with STOCK rocker arms
80" EVO - FXR4
SE Heads w/Adj pushrods
.030 HG Wood W6 Cam HSR42 Carb

Offline gryphon

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #3 on: Sunday, February 15, 2009. 01:17:53 PM. »
Both of your sentiments mirror mine. My motor originaly came with a much higher lift cam and as a result the roller rockers were fitted. I'm not going to get rid of my rollers but I also see no real reason for buying another set of spendy rockers when a nice set of standard rockers is so much cheaper and capable of doing the job.

Offline Scott P

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #4 on: Sunday, February 15, 2009. 02:09:51 PM. »
I know that with a high lift cam it's a good idea to use roller rockers so that you don't have  the face of the rocker arm constantly rubbing against the top of the valve stem as it opens and closes. I guess this can't hurt anything even on a low lift cam but, at about what point would you have to say that "yes, from this point and up you should use roller rockers". I'm starting a new build and will be using the heads and rocker assembly's from my present S&S motor to complete the new one. Since I'll have pretty much a whole motor just sitting here I figured I'd collect parts to maybe finish the old one off. The cam in it has a .500 lift which is fairly mild by the standards of the day. I would think that standard rocker arms should be just fine. Any opinions. What would be the highest lift before rollers started becoming almost mandatory.

At .500 lift, your stock hammers are fine.
When getting into aggressive ramp cams, we like to see them at anything over .560-570.
At .630 lift or more, well feel that is an absolute must.
"If I parrot or google information, folks will suspect I really know."

Offline Buddy WMC

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #5 on: Sunday, February 15, 2009. 02:13:27 PM. »
I know that with a high lift cam it's a good idea to use roller rockers so that you don't have  the face of the rocker arm constantly rubbing against the top of the valve stem as it opens and closes. I guess this can't hurt anything even on a low lift cam but, at about what point would you have to say that "yes, from this point and up you should use roller rockers". I'm starting a new build and will be using the heads and rocker assembly's from my present S&S motor to complete the new one. Since I'll have pretty much a whole motor just sitting here I figured I'd collect parts to maybe finish the old one off. The cam in it has a .500 lift which is fairly mild by the standards of the day. I would think that standard rocker arms should be just fine. Any opinions. What would be the highest lift before rollers started becoming almost mandatory.

At .500 lift, your stock hammers are fine.
When getting into aggressive ramp cams, we like to see them at anything over .560-570.
At .630 lift or more, well feel that is an absolute must.


Well stated and I agree 100% with Hillside. When I went to .595 lift, the roller rockers were installed. I bought good parts, so absolutely 0 problems and the valvetrain is quiter that it was with the EV-27 and stock rockers.

Offline ClassicRider2002

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #6 on: Sunday, April 25, 2010. 07:23:43 AM. »
-

Alright I was doing some research....and found this THREAD, so I thought I would throw in some thoughts on the matter and get some additional insight:

According to "Donny Peterson" American Iron, not that he is an "absolute" authority I was reading and I quote:

TWIN CAM PERFORMANCE   PART II  SOME WAYS TO INCREASE YOUR TWIN CAM'S POWER
THE VALVETRAIN    AmericaN IRON JANUARY 2006  BY DONNY PETERSON

R'dR either never read an article on roller rockers, or else his wrench neglected to put them in, which is unforgiveable in the world of high performance.  Roller rocker arms are a good idea (if affordable), even in a stock pushrod-operated engine.  However, as cam lifts approach .570" in the TWIN CAM, they become necessary.  Don't even go near the .585" lift cams unless you can afford to install the roller rocker arms.

Because EVO pushrods are at exaggerated angles compared with the TWIN CAM, they need roller rockers at Lower lifts like .525".  (There are many excellent manufacturers of roller rocker arms, like S&S, Crane, and JIMS).

As each cam lobe rotates to its highest postion, the hydraulic lifter's roller follows its path over th lobe, pushing the hydraulic lifter up.  This, in turn, forces the pushrod up, causing the rocker arm to rotate, pushing down on the top of the valve stem to open the valve.  More precisely, the rocker arm rubs across the top of the valve stem as it pushes the valve open.  This rubbing pushes the valve against the side of the valve guide, which ultimately causes unwanted wear and resistance because of the additional friction.  Anything that can lessen this side thrust--- such as a roller going across the top of the valve instead of a curved steel pad--- is a big bonus in the terms of efficiency and horsepower. Internal engine friction, known as frictional horsepower loss, lessens available horsepower.  Of course, if the valve were at a 90-degree angle (straight up and down), there would be no side load.

The roller rocker arms are superior to the stock "rubbing" arms. The tip of a roller rocker arm, which actuates the valve, has a roller supported by a bearin.  It's this roller that pushes the valve open with minimal resistance by rolling across the top of the angled valve as opposed to rubbing across it.  As the lift of the cam increases, so does the amount of side loading, friction, and inertia, which leads to premature wear and a "heavier" valvetrain.  Roller rockers, along with low-friction valve guides, act in concert to trick the valvetrain into reacting as though it is lighter.  This is very important because it relates to valve float with high-lift cams and/or high-rpm riding.

So here are my questions:

1.  Obviously some don't always prescribe to Donny Peterson's theories or positions which is fine, but because of reading this I am curious what roll "roller" rocker arms should play in a "mild" evo build.  So should one use a "roller rocker" arm if they are going to use a .525" lift cam? 

2)  What if one wants to use a .500" lift cam and wants to use a high lift rocker arm with this combination presenting one with approx an approximate modified cam lift of .525"?

3)  If you support "roller rocker arms" and you want to use a "high lift rocker arm" who makes a "High Lift ROLLER Rocker Arm for an EVO application?


I would appreciate any comments from builders, obviously the EVO engine has had it's day so most of the R&D is over with now given we are in 2010 so many years removed, I am just curious how the rocker arms should play out, no sense spending "wasteful" money as most who repsonded above thought they were not needed, so any other reflections? ? ?

Regards,

"Classic"
« Last Edit: Sunday, April 25, 2010. 07:28:08 AM. by ClassicRider2002 »
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Offline wfolarry

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #7 on: Sunday, April 25, 2010. 07:50:34 AM. »
I like roller rocker arms. I've been running them since they first came out [Crane] & I still have them in my bike. Rebuilt them a couple years ago but otherwise no problems.
I'll try to answer your questions. If I don't ask a specific question & I'll answer it.
Cam design & spring pressure dictate whether a roller is needed more than lift. If you have .500 lift but the lobe looks more square than round you would need a stronger spring to control it so a roller will help. On the other hand if you have .600 lift but the lobe looks like an egg you could get away without them. On TC's with the beehive spring you see this more. On an Evo a .600 lift cam would require a spring change & that usually means more pressure. Sort of a double edge sword.
Jim's has them. I'm pretty sure S&S has them too but I'd have to check on that.

Offline baldoldfxr

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #8 on: Sunday, April 25, 2010. 08:46:05 AM. »
"obviously the Evo engine has had its day" There are a lot of people & manufacturers S&S etc who would disagree

Offline ClassicRider2002

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #9 on: Sunday, April 25, 2010. 10:10:38 AM. »
-

"obviously the Evo engine has had its day" There are a lot of people & manufacturers S&S etc who would disagree

baldoldfxr~

I appreciate your reflections for SURE!
What I meant by that of course is that while it continues on in the aftermarket and with us that own them....."its had its day" was meant to be reflective that time moves forward and these become the "older" version vs the newer version persay.  I however agree with you.....I really enjoy my 99 FXR2 with the "evo" engine.

---------------

".....Cam design & spring pressure dictate whether a roller is needed more than lift. If you have .500 lift but the lobe looks more square than round you would need a stronger spring to control it so a roller will help. On the other hand if you have .600 lift but the lobe looks like an egg you could get away without them....."

Given what you were expressing above WFOLarry I will simply provide the cam I am going to run in my 99 FXR2 in order to provide better insight.  Since I have had appropriate success with my "MOUSE CAM" in my 2002 RKC, I am now looking to modify my FXR2 with some similar types of thoughts....here is what I am after:

Please remember the uniqueness of the CVO FXR's is that they are running 2.925 Final Gearing which is pretty high....also be aware that the FXR2 in particular weights in at 560 lbs wet!

I will be keeping my cylinders stock, no desire to "bump" them up, At some point I may do some porting of my oem heads, [actually in order to take advantage of the "high lift" benefits of going with "stilts" will require some porting of my OEM heads, I get that.] for a bit more air flow to match my particular cam choice....but my thoughts are to accomplish two things.....bring down the intake close angle a bit more from 39 to 34 and to also raise the lift which will also modify my duration some 2-4 degrees by working with the high lift rocker arms going from 1.625 oem to 1.725 with the sreamin eagle high lift rocker arms...ie: STILTS.....this will effectively change the characteristics of the EVL-3000 from a .500 lift to an approx lift of .530".  I am also running the V&H 2-1 pro pipe.  This discussion for me isn't so much about my cam choice or looking for opinions necessarily as the cam has already been purchased, really my thoughts are trying to address whether there is reason enough to support "roller" rocker arms vs simply not having them as Donny Peterson mentioned above....and it appears to me that HD SE doesn't offer the "high lift" rocker arms in a "roller arm" style, so that would mean if there is enough support to justify the use of "roller" arms what brand works better than others persay? ? ? ?

I have been currently running an EVL 3010 which has these specs:
EVL-3010
Lift: .500 /.500
Lobe Lift:  .3125 / .3125
Duration:  234 / 234
Valve Timing Open / Close:   in.: 15/39/ ex.: 39/15
Lobe Center Line:  102 / 102
Lobe Seperation:  102
Base Circle Radius: .530
Tappit Lift @ TDC:  .096" / .096"
Valve Lift @ TDC:  .154" / .154"

Modifying to THIS:

EVL-3000:
Lift: .500 /.500
Lobe Lift:  .3125 / .3125
Duration:  224 / 224
Valve Timing Open / Close:   in.: 10/34/ ex.: 34/10
Lobe Center Line:  102 / 102
Lobe Seperation:  102
Base Circle Radius: .530
Tappit Lift @ TDC:  .080" / .080"
Valve Lift @ TDC:  .128" / .128"

What I am attempting to discover is input on the "merits" of using roller rocker arms since my end result may be taking my lift of a .500" lift cam up to .530" lift and I was a bit concerned reading about how Donny Peterson without hesitation thought that any evo engine running greater than say a .525 lift should definitely be using "roller" arms....

All input welcomed!!!!

Regards,

"Classic"




 
« Last Edit: Sunday, April 25, 2010. 10:19:38 AM. by ClassicRider2002 »
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Offline wfolarry

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #10 on: Sunday, April 25, 2010. 10:28:01 AM. »
Back when the Evo's came out there weren't a lot of cams out there. My bike is an '85 so it didn't have reliefs cut in the pistons. The cam I put in was a Kateley [ever heard of that one?] that would work with my setup. The bike ran good. A couple years later came the rollers. Put the rollers in nothing else. The difference was easily felt. The bike ran much better. Comes back to the cam design. I still have them in there with a different cam but they're still rolling along. And for the naysayers I've ridden this bike all over the country quite a few times & have never had a motor problem. I like rollers & while I'll admit they aren't a necessity I recommend them for all high output applications. The decision is yours.

Offline jclark311

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #11 on: Sunday, April 25, 2010. 08:04:10 PM. »
Here is my 2 cents. I read this in the book 101 Harley Davidson Performance Projects For Evo Big Twin, and Sportster. I would recomend this book to anyone with an Evo Motor. It has so much info. I got it on Amazon for 20.00. Project 48 is Installing Roller Rockers. In the book the author claims that the pusrods on Evos are at less than a desireable angle, when you add a highlift cam, and mill the heads, that angle gets worse.I am installing an Andrews EV27 Cam, and my heads are out getting milled, so I found a reasonably price Roller Rocker at Jireh Cycles. The part number id 91-699, price is 109.95. This rocker has a 1.675 ratio, stock is 1.625, so your 500 lift cam will be a little more, but I dont think its enought to worry about. I have had my Ultima 113 for 7 years now, those are the rockers on there, and I have had no problems.

Offline glens

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Re: At what lift would roller rockers start becoming a necessary upgrade
« Reply #12 on: Sunday, April 25, 2010. 08:30:11 PM. »
How does the pushrod angle have anything whatsoever to do with the way the other end of the rocker interfaces with the valve stem?

[quoted material?] Of course, if the valve were at a 90-degree angle (straight up and down), there would be no side load.
That one really cracked me up.