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Old 11-26-2013, 10:36 PM
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Roller rocker arm durability, under 7000rpm

Looking for personal experiences of those who have street driven a brand of roller rockers and can attest to their durability. Obviously a solid cam places more stress on the valvetrain with this style of rocker so I would place more weight on those experiences.

So many choices out there from many different mfgs and quite a few horror stories as well, let's leave the pedestal mount Jesel style models out of this for now as it's out of range for the average rodder.

To be exact I'm looking for a SBC 3/8" post in 1.6 ratio and need a good recommendation from a member of the board who has put some serious street miles on theirs and can say they work without coming apart over time.

It would seem many installs don't have deflectors to keep them and the springs properly cooled and lubricated so I wonder how many of those horror stories are from poor setups.

What say you?

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Old 11-26-2013, 10:57 PM
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I have not and wont likely use 1.6 roller rockers on the street,just buy the correct cam to start.
I have used Crane roller (aluminum) rockers on a street driven small block 355 in a 1967 Camaro,that I had for 5 years.(It was stolen) The heads were GM cast iron,the cam was a .505 solid with 315 advertised duration. The car was driven almost everyday. It made 2 long trips(for a bracket motor) from Vancouver BC to Bremerton,with 5.13 gears,,,3700 RPM all the way there,got lost and drove an extra hour.
same car Vancouver to Seattle,both trips included racing and driving home.
same rockers were used when I later got a used roller cam from Richard Johnsons 56 chevy SS 265. I then used 5.57 gears and trailered the car for as long as I owned it.
Many failures,never a rocker arm
I now use Jessel rockers with mixed ratios
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Old 11-27-2013, 12:09 AM
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Lots of reasons why I want to use 1.6 ratio rockers, primarily I am duplicating the ZZ430 crate motor from GMPP which used the LT4 cam and 1.6 rockers. I already have the proper AL 604 heads which I lucked out on finding cheap.

The GMPP "Hot cam" P/N 846 which was a part of this package has a 0.525" lift with the 1.6 rockers which is max for the stock springs, looked hard for an aftermarket cam that is similar but everything is either way higher or lower lift or too little duration or too much.

I've thought about stepping up to the next level cam P/N 847 but then I need new springs, this is what is used in the ZZ465 crate engine and honestly the car won't need more power for the application.

The car is a FC 1987 Mazda RX7 TurboII with 4.33:1 rear axle, about 2600 pds total. Engine is a late model 4 bolt main Gen I roller block about 10:1 comp with a TH400 trans.

I'm going to use the stock exhaust so it's quiet and a radical cam would give it away, the car will be autocrossed so big cams are useless when precision and a broad flat torque curve is key.

Here's the car, engine will be relocated about 5" rearward with front and mid motor plates.


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Old 11-27-2013, 05:33 AM
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Most aluminum roller rockers that are 1.5 are really 1.6 ratio out of the box, their made like that to account for flex. I don't think you could go wrong with steel rollers rockers. I've had 1.6 roller tipped rockers (Crane) self aligning on my Vortec heads for 5 yrs. now with no problems. Not full rollers but they work an I don't worry about them.
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Old 11-27-2013, 05:48 AM
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Quote:
Originally Posted by vinniekq2 View Post
I have not and wont likely use 1.6 roller rockers on the street,just buy the correct cam to start.
Who in the hell started this idea that 1.6 rockers are somehow wrong? It must have been some idiot who never built anything besides a stock sbc as there are many many many engines that comes from the factory with other ratios. Also, how is it better to run a steeper love rather than more rocker ratio to achieve the same lift?

As for durability- can't argue with what the general uses in their crate and hot cam packages.

I've logged a lot of miles on Harland sharp rockers myself. Any reputable brand should be fine provided they're installed and oiled properly.
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Old 11-27-2013, 09:46 AM
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The Scorpion aluminum roller rockers have worked very very well for me.
The 1.6 's apparently actually check at 1.65:1.
GMPP is switching over to using the LS3 Beehive springs on most all these crate motors now.
I suggest you do the same. GMPP has a retainer for that now too.
Comp 787-16 retainer works too.
You can shim the beehives to adjust installed height and pressure as required.
The beehive springs control the Valvetrain better.

http://www.scorpionperformance.com/

When I need a aluminum roller rocker arm this is what I use.

It is important to note that when switching from a stock type rocker arm to a aluminum roller that you look at the pushrod length and rocler geometery/roller tip sweep pattern on the valve tip.
Some rockers have a different relative pushrod seat location/geometry requiring a pushrod length change to get it right.
This modified pushrod seat location modifies the valve lift curve/complex rocker arm ratio curve as the valve actually opens and closes.
So there is more to it than just a raw simple ratio change.
The Scorpion rockers work good.

Last edited by F-BIRD'88; 11-27-2013 at 09:59 AM.
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Old 11-27-2013, 11:18 AM
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Quote:
Originally Posted by 4 Jaw Chuck View Post
Looking for personal experiences of those who have street driven a brand of roller rockers and can attest to their durability. Obviously a solid cam places more stress on the valvetrain with this style of rocker so I would place more weight on those experiences.

So many choices out there from many different mfgs and quite a few horror stories as well, let's leave the pedestal mount Jesel style models out of this for now as it's out of range for the average rodder.

To be exact I'm looking for a SBC 3/8" post in 1.6 ratio and need a good recommendation from a member of the board who has put some serious street miles on theirs and can say they work without coming apart over time.

It would seem many installs don't have deflectors to keep them and the springs properly cooled and lubricated so I wonder how many of those horror stories are from poor setups.

What say you?
The 350 in my S15 has 360,000 miles on a set of 1.6, Jim Miller, Mid Lifts which are full roller trunion and tip in a fat aluminum housing. No failures of bearings nor fatigue issues with the rocker itself. But of course Jim doesn't make these any more.

Bogie
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Old 11-27-2013, 11:41 AM
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Quote:
Originally Posted by ap72 View Post
Who in the hell started this idea that 1.6 rockers are somehow wrong? It must have been some idiot who never built anything besides a stock sbc as there are many many many engines that comes from the factory with other ratios. Also, how is it better to run a steeper love rather than more rocker ratio to achieve the same lift?

As for durability- can't argue with what the general uses in their crate and hot cam packages.
It makes little sense to use 1.6 rockers on a street motor small block Chevy. Now, if you're talking race motor, great, knock yourself out, use 1.8 rockers if you can make them work. But here on this forum, we're dealing with fellows who are looking for a little more grunt from their street motor, not looking for every last horsepower and making the valvetrain work harder than it has to. We have enough trouble with fragging cams and lifters as it is, without adding fuel to the fire.

A change from 1.5 to 1.6 adds 16% more effort to the cam lobe and the lifter crown for a return of ~10-15 horsepower in most cases. What difference does it make if the motor is making 400 hp or 410 hp? The driver ain't gonna feel it in the seat of his pants anyway.

You do what you feel you have to do and I'll continue advising against higher ratio rockers on street motors, favoring long life rather than extracting every last horsepower from a motor.
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Old 11-27-2013, 02:15 PM
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Adding 1.6or 1.65 rockers especially on the intake side can be very effective when more lift at the valve
is desired. But a cam seat to seat duration change is not desired.

Especialy effective once the SBC head has been ported as most of the flow gain from porting is realized at higher valve lifts.

EG: a .450" valve lift with a 1.5 rocker becomes a .495" lift when 1.65:1 rockers are used.
Duration remains the same. Max lift and upper lift valve open area is increased right where you can use it with a ported SBC head. The valve lift change factor is 1.1 for a 1.5 to a 1.65 change.

The exhaust port side tends to respond more to cam duration changes.

here is a wexample of effective use of higher ratio rockers.
Cam 214-224 @.050 .442"in .465"ex @1.5 112LSA hyd flat tappet.

swap on 1.65 in and 1.6 exhaust valve lift becomes .486" in .495" ex
Duration stays the same but upper area and peak valve lift is increased.
Much like the gain seen when a hyd roller cam is used.
But at flat tappet cam prices. now the valves lift high enough to allow a ported head to flow more.

Another example:
Crane Powermax H278-2 (HMV 278-2) camshaft (one of my favorite little street blower-nitrous cams)
278-290 222 234 @.050" .467" in .494"ex 1.5 rockers.
Now swap on a 1.65 intake rocker only
net valve lift is now .513" intake .494" exhaust (no change)
More intake valve lift, very near hyd roller cam valve lift curve and performance but at a flat tappet cam price.
Lets a ported street head work.
Duration stays the same.

Last edited by F-BIRD'88; 11-27-2013 at 02:38 PM.
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Old 11-27-2013, 02:49 PM
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Now you picked up 30 horsepower. That makes a difference.

Using the GMPP beehive valve springs really maxes the effectiveness of this rocker mod on a street/strip SBC.

Last edited by F-BIRD'88; 11-27-2013 at 02:55 PM.
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Old 11-27-2013, 03:05 PM
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For durability/endurance, I always use steel rockers, whether they are Crower, Comp or the long ago Norris. I have never had one fail.
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Old 11-27-2013, 03:26 PM
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I favor a steel or cast rocker as well over aluminum for a street motor as well.A lot of the better aluminum rockers are considerably larger & most require tall valve covers,or'removing baffles.In my case,tall covers won't work unless I wanna get real creative with my A/C,or'do w/o it.
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Old 11-27-2013, 03:29 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
The Scorpion aluminum roller rockers have worked very very well for me.
The 1.6 's apparently actually check at 1.65:1.
GMPP is switching over to using the LS3 Beehive springs on most all these crate motors now.
I suggest you do the same. GMPP has a retainer for that now too.
Comp 787-16 retainer works too.
You can shim the beehives to adjust installed height and pressure as required.
The beehive springs control the Valvetrain better.

Welcome to Scorpion Performance

When I need a aluminum roller rocker arm this is what I use.

It is important to note that when switching from a stock type rocker arm to a aluminum roller that you look at the pushrod length and rocler geometery/roller tip sweep pattern on the valve tip.
Some rockers have a different relative pushrod seat location/geometry requiring a pushrod length change to get it right.
This modified pushrod seat location modifies the valve lift curve/complex rocker arm ratio curve as the valve actually opens and closes.
So there is more to it than just a raw simple ratio change.
The Scorpion rockers work good.
F'Bird,do you have the part# for the GM retainers?I heard they have em,but,haven't found any.
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Old 11-27-2013, 04:29 PM
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Quote:
Originally Posted by 4 Jaw Chuck View Post
Looking for personal experiences of those who have street driven a brand of roller rockers and can attest to their durability. Obviously a solid cam places more stress on the valvetrain with this style of rocker so I would place more weight on those experiences.

So many choices out there from many different mfgs and quite a few horror stories as well, let's leave the pedestal mount Jesel style models out of this for now as it's out of range for the average rodder.

To be exact I'm looking for a SBC 3/8" post in 1.6 ratio and need a good recommendation from a member of the board who has put some serious street miles on theirs and can say they work without coming apart over time.

It would seem many installs don't have deflectors to keep them and the springs properly cooled and lubricated so I wonder how many of those horror stories are from poor setups.

What say you?
468 BBC with a 710" camshaft. Spin it up to 7400/7600 on occasion. Street/strip car and has been together for 6 years and havnt hurt anything yet. I used the Crower rockers.
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Old 11-27-2013, 06:43 PM
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I bought a gen II RX-7 in January 1986.I loved that car,mine was a GXL 2+2. If you V-8 that car take the time to get the weight and balance correct again. Great driving car,only slightly less as good at handling as the 944 turbo and less than 1/2 the cost. I wish my Corvette handled that well.
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