Moparts
How do roller rockers improve performance?
Posted By: cal_gecko
How do roller rockers improve performance? - 06/09/14 07:36 PM
Friend of mine told me I should ditch the factory shaft-mounted rockers on my 360 (non-Magnum) and go with something like this:
http://www.ebay.com/itm/PRW-SB-Mopar-273...30f&vxp=mtrSaid it would be a significant performance improvement. How does this improve performance?
Posted By: JohnRR
Re: How do roller rockers improve performance? - 06/09/14 07:42 PM
Those rockers would improve performance because of the ratio change from what your current rockers are , CLAIMED 1.5 , to a claimed 1.6 , increase lift and duration without a cam change.
There is no real performance gain by just switching to a roller tipped rocker.
The quality of those rockers ???
Rockers arms are one place to not buy cheap Chinese junk . Ask those that bought off shore big block rockers because they were CHEAP , only to have them cause a dropped valve ...
Posted By: cal_gecko
Re: How do roller rockers improve performance? - 06/09/14 07:55 PM
Quote:
Those rockers would improve performance because of the ratio change from what your current rockers are , CLAIMED 1.5 , to a claimed 1.6 , increase lift and duration without a cam change.
There is no real performance gain by just switching to a roller tipped rocker.
The quality of those rockers ???
Rockers arms are one place to not buy cheap Chinese junk . Ask those that bought off shore big block rockers because they were CHEAP , only to have them cause a dropped valve ...
Wow .. are those considered 'cheap'? $400+ ?
Posted By: Challenger 1
Re: How do roller rockers improve performance? - 06/09/14 07:58 PM
Quote:
Friend of mine told me I should ditch the factory shaft-mounted rockers on my 360 (non-Magnum) and go with something like this:
http://www.ebay.com/itm/PRW-SB-Mopar-273...30f&vxp=mtr
Said it would be a significant performance improvement. How does this improve performance?
For a LA SB I would stay with 1.5 rockers, with a good set of aftermarket 1.5s, your going to have more lift than from stock rockers and a little less friction.
I wouldn't call it significant even with 1.6 rockers.
Posted By: autoxcuda
Re: How do roller rockers improve performance? - 06/09/14 08:01 PM
IIRC, you have an comp XE-268 hyd cam.
I the performance increase per dollar spend is low. Better places to spend money.
Good chance you'll need new pushrods too. And those should be custom ordered to what you exactly need after checking with a pushrod measuring setup to see if what you have now is ok. S AKA: snow ball effect.
Posted By: cal_gecko
Re: How do roller rockers improve performance? - 06/09/14 08:09 PM
thanks guys..
AutoXCuda - good memory on the cam
yeah... snowball effect is not what I need.
I'll just drive it and enjoy it
Posted By: autoxcuda
Re: How do roller rockers improve performance? - 06/09/14 08:59 PM
Quote:
...
yeah... snowball effect is not what I need (MORE OF).
...
Posted By: 360view
Re: How do roller rockers improve performance? - 06/09/14 09:02 PM
It is worth noting that recent high performance pushrod engines seem to be avoiding roller rockers.
Maybe the rollers make the rocker either too heavy or less stiff.
Recent rocker designs seem to emphasize lightness and stiffness, as do pushrods.
In the book "Chrysler Engines" former chief engineer Willem Weertman writes that roller hyd lifters improved the fuel economy of the Magnum upgrade series of engines, particularly the 3.9 V6 version.
Roller rockers are certainly not new.
Rudolf Diesel's original compression-ignition engine had a roller rocker.
Posted By: nomore65BelvJim
Re: How do roller rockers improve performance? - 06/09/14 09:03 PM
Reminds me of the old "Lit" song
Posted By: cal_gecko
Re: How do roller rockers improve performance? - 06/09/14 09:10 PM
Quote:
Quote:
...
yeah... snowball effect is not what I need (MORE OF).
...
Posted By: Pyper70
Re: How do roller rockers improve performance? - 06/09/14 11:06 PM
I didn't even open the link in the OP...
PRW...Chinese junk....don't grenade a motor for that stuff...I bought the 44 Source for $400 many moons ago and never installed em for fear of those exploding needle bearings...Why ditch a motor for a couple hundred bucks...I bought Harlands and it runs like a dream
Posted By: DaytonaTurbo
Re: How do roller rockers improve performance? - 06/09/14 11:55 PM
For your cam... a waste of money IMO. If you're running a solid cam or an aggressive hydraulic, then you need em. Yes there may be (very) slight gain because factory rockers often don't spec out to the true 1.5 ratio they are supposed to be, often in the 1.4 range. But that would be a terrible bang for buck upgrade in your case.
Posted By: Sinitro
Re: How do roller rockers improve performance? - 06/10/14 12:56 AM
Quote:
Those rockers would improve performance because of the ratio change from what your current rockers are , CLAIMED 1.5 , to a claimed 1.6 , increase lift and duration without a cam change.
There is no real performance gain by just switching to a roller tipped rocker.
The quality of those rockers ???
Rockers arms are one place to not buy cheap Chinese junk . Ask those that bought off shore big block rockers because they were CHEAP , only to have them cause a dropped valve ...
Are U aware the PRW rockers are made in China... 
Most likely made from recycled Coors cans...
The valve train is not a place to save $ buy the quality proven brands..
Just my $0.05...
Posted By: BSB67
Re: How do roller rockers improve performance? - 06/10/14 02:42 AM
Quote:
....often in the 1.4 range.....
And the number keeps getting lower.
Posted By: 383man
Re: How do roller rockers improve performance? - 06/10/14 03:10 AM
In theory the roller has less drag to loosen up hp. How much. Maybe none. One good thing they do is put less wear on the valve guide since the roller will glide across the top of the valve easier and not put as much push on the valve to the side when opening. But if I was spending $400 or more dollars and looking for a performance gain I would not be buying roller rockers. Ron
Posted By: ahy
Re: How do roller rockers improve performance? - 06/10/14 03:13 AM
Agree the roller tip helps at higher lifts. It reduces "scrub" across the top of the valve. Rule of thumb over .5" orso lift. With a mild cam not much help.
If you push the cam or ratio up then you have to look at stiffer springs. With stiffer springs stiffer pushrods. As you say, it snowballs.
Posted By: TJP
Re: How do roller rockers improve performance? - 06/10/14 03:15 AM
Quote:
In theory the roller has less drag to loosen up hp. How much. Maybe none. One good thing they do is put less wear on the valve guide since the roller will glide across the top of the valve easier and not put as much push on the valve to the side when opening. But if I was spending $400 or more dollars and looking for a performance gain I would not be buying roller rockers. Ron
Posted By: MoparforLife
Re: How do roller rockers improve performance? - 06/10/14 04:10 AM
Here from one of the Mopar mags:
Posted By: 4speeds4me
Re: How do roller rockers improve performance? - 06/10/14 06:35 AM
I remember reading an article years ago that stated that roller rockers were one of the BIGGEST money wasters in the average street engine...$400 (since that's the dollar figure floating around in this thread) will give you noticeable gains in the heads, but you'll likely never see it in the rockers.
They'll sure look purty, though!
Posted By: cedarmachine
Re: How do roller rockers improve performance? - 06/10/14 06:45 AM
If you think they are a "bolt on" part, you may be in for a surprise when the pushrods all hit the heads.
They move the pushrod seat towards the fulcrum to get the additional ratio. This usually leads to a clearance problem. Some guys bend up a few sets of pushrods before they figure this out.
Posted By: cal_gecko
Re: How do roller rockers improve performance? - 06/10/14 07:22 AM
Quote:
I remember reading an article years ago that stated that roller rockers were one of the BIGGEST money wasters in the average street engine...$400 (since that's the dollar figure floating around in this thread) will give you noticeable gains in the heads, but you'll likely never see it in the rockers.
They'll sure look purty, though!
so are you saying I'd be better off spending $400 in head work than changing out the rockers?
Posted By: 451Mopar
Re: How do roller rockers improve performance? - 06/10/14 07:45 AM
Adjustable rockers allow you to adjust lifter pre-load with a hydraulic cam, or lash on a solid cam.
Higher ratios rocker arms allow more lift at the valve which makes the cam seem a bit larger.
The roller tip rockers are supposed to eliminate the rubbing action across the tip of the valve stem. This feature is more important when using higher lift cams with higher valve spring pressures.
Full roller rockers with rollers on the rocker shaft are supposed to help reduce friction.
The stock rockers do a good job, but the actual rocker ratio is less than 1.5:1, and with higher valve spring pressures, the pushrod can break through the rocker arm. They are also non-adjustable.
On a small block, if you goto a higher rocker ratio like 1.6:1, you should enlarge the pushrod holes in the cylinder heads, because the higher ratio comes from moving the pushrod closer to the center of the rocker arm.
You will likely need new custom length pushrods too.
As for the quality of rocker arm, alot depends on your valve spring pressures. I have a friend who is running those rocker arms on a really mild (near stock) engine and he says they are fine?
I bought a set of the identical looking "CAT" rocker arms for my 440, and they had issues with the roller tips wearing. I think the stainless bodies of the rockers are OK. They had good geometry, but really to be useful they would have to be rebuilt with hardened roller tips and pins, and the adjusters replaced with better quality ones. Anyhow, I learned my lesson and I'm running Harlan Sharpe rockers on my 440 now.
Posted By: 4speeds4me
Re: How do roller rockers improve performance? - 06/10/14 08:12 AM
That's what I'm saying. I know lots of guys like them, and at times, so do I. But under .550" lift, that money can be better spent getting air in and out...and as far as side loading of the valve or scrubbing the tip is concerned, how many miles do the average one of us put on these cars? In 10 years we MIGHT have worn things enough to cause an issue.
All that said, if you're in a position where you NEED to buy rockers (change to solid cam, preload issues, etc) then buying a quality set of adjustables/pushrods isn't a bad idea, and roller tipped are going to be marginally more expensive...
Posted By: cal_gecko
Re: How do roller rockers improve performance? - 06/10/14 09:18 AM
Quote:
That's what I'm saying. I know lots of guys like them, and at times, so do I. But under .550" lift, that money can be better spent getting air in and out...and as far as side loading of the valve or scrubbing the tip is concerned, how many miles do the average one of us put on these cars? In 10 years we MIGHT have worn things enough to cause an issue..
I've put 3300 miles on the Dart since the beginning of December
Posted By: slantzilla
Re: How do roller rockers improve performance? - 06/10/14 11:56 AM
I have a set of 1.6 ratio rollers for my Slant. I normally run stock rockers which are in the neighborhood of 1.5. I tried them back to back to back against each other the same day at the track. There was 0 difference. This was with a good ported head and a .560" lift cam.
Posted By: CokeBottleKid
Re: How do roller rockers improve performance? - 06/10/14 12:12 PM
Not worth the time on a small hydraulic like that with stock 360 heads.... Only makes a difference if you're giving up flow on a set of heads with not enough lift. Even then it's small gains at that. Your stock 360 heads probably stall at around .450-.500 lift anyways so I wouldn't bother.
Posted By: 6PakBee
Re: How do roller rockers improve performance? - 06/10/14 12:18 PM
I like stock rockers because of their simplicity, cost, and that they are part of a total engineered package. The only drawback is that the ratio is all over the map. What I did years ago was get a bunch of rockers and check the lift on each one. Then I split them into intake and exhaust sets that had approximately the same ratio. Worked well so far. As to the technique, it isn't mine, Racer Brown was promoting this 35 years ago.
Posted By: JohnRR
Re: How do roller rockers improve performance? - 06/10/14 03:27 PM
Quote:
Quote:
Those rockers would improve performance because of the ratio change from what your current rockers are , CLAIMED 1.5 , to a claimed 1.6 , increase lift and duration without a cam change.
There is no real performance gain by just switching to a roller tipped rocker.
The quality of those rockers ???
Rockers arms are one place to not buy cheap Chinese junk . Ask those that bought off shore big block rockers because they were CHEAP , only to have them cause a dropped valve ...
Are U aware the PRW rockers are made in China...
Most likely made from recycled Coors cans...
The valve train is not a place to save $ buy the quality proven brands..
Just my $0.05...
Here's the one time I don't go on a tyrade on cheap chinese junk so I don't get banned AGAIN because I'm not a board sponsor sword swallower and I still get crap ...
YES those PRW rockers are cheap chinese junk , it appears the OP got that out of what I posted because he was surprised that I consider 400 some odd dollars CHEAP , seriously I thought the price was less , I just saw PRW and closed the link ...
That aside I also answered his question pertaining to a performance increase which a 1.6 ratio rocker would provide , granted it wouldn't be much .
Posted By: MoparforLife
Re: How do roller rockers improve performance? - 06/10/14 06:27 PM
With rollers you will of course get the 'WOW' factor. Another point against rollers on the street is that they do self destruct and when they do it put little rollers into your engine. (Even the spendy ones can and do do this at times) Not a fun thing. I have run constant 11.40's with dips into the 11.30's with HD stock pressed type rockers in a fairly mild 360 in a Duster. Remember that there is a left and right rocker.
Posted By: BDW
Re: How do roller rockers improve performance? - 06/10/14 07:22 PM
From reading this the main knock seems to be the stock parts aren't really 1.5 while the rollers are 1.6.
Any reason, or maybe its already available, why not have "true" 1.5 or 1.6 stamped parts?
Posted By: autoxcuda
Re: How do roller rockers improve performance? - 06/10/14 07:35 PM
Quote:
From reading this the main knock seems to be the stock parts aren't really 1.5 while the rollers are 1.6.
Any reason, or maybe its already available, why not have "true" 1.5 or 1.6 stamped parts?
Usually with roller you have a choice between 1.5 and 1.6
Stamped and stock cast adjustble 273 rockers are around 1.43 to 1.45 IIRC? 
Running a high lift version of your cam is a way to net out roughly the same as with a 1.5 rocker. Valve doesn't care what ratios it takes to get it to a certain place. If it gets there, it gets there. 
Posted By: MoparforLife
Re: How do roller rockers improve performance? - 06/11/14 02:46 AM
Quote:
From reading this the main knock seems to be the stock parts aren't really 1.5 while the rollers are 1.6.
Any reason, or maybe its already available, why not have "true" 1.5 or 1.6 stamped parts?
You can get true 1.5 or 1.6 doctile iron adjustable rockers that are non roller. But there again you will need to get push rods for adjustable rockers with hydraulic lifters.
Posted By: Kern Dog
Re: How do roller rockers improve performance? - 06/11/14 04:38 AM
Quote:
Here's the one time I don't go on a tyrade on cheap chinese junk so I don't get banned AGAIN because I'm not a board sponsor sword swallower and I still get crap ...
You've been banned before, too?
Last Summer I switched to a solid lifter cam. Prior to the cam swap I put in a set of aluminum rocker arms offered by Mancini racing. They are made by Harland Sharp.
Regarding the inconsistant ratios of stock rocker arms, I can report this: My cranking compression spread between the lowest cylinder and the highest tightened up when I put the new rocker arms in. My take is that the new stuff was more accurate and the result was a more evenly matched ratio for all cylinders.
Posted By: 4speeds4me
Re: How do roller rockers improve performance? - 06/12/14 09:18 AM
Quote:
Quote:
That's what I'm saying. I know lots of guys like them, and at times, so do I. But under .550" lift, that money can be better spent getting air in and out...and as far as side loading of the valve or scrubbing the tip is concerned, how many miles do the average one of us put on these cars? In 10 years we MIGHT have worn things enough to cause an issue..
I've put 3300 miles on the Dart since the beginning of December
That's my point! 3300 miles in 6 months, so, say, 7000 for the year. That's only 70,000 in 10. I put over 50,000 on my truck in 1.5 years!
