Full roller rockers for street?
Thread Starter
Pro
Joined: Dec 2014
Posts: 530
Likes: 10
Full roller rockers for street?
I am planning on going to 1.6 ratio rockers on my early C4 along with a hydraulic roller cam and double roller timing set... I was planning on buying rockers with roller fulcrum like the Comp Cams Ultra Pro Magnum and not just roller tip like the Magnums.
Will this be an issue for long term street durability? A friend of mine says he's seen a lot of failures in roller rocker arms... but that may just be in the aluminum body ones. The Ultra Pro Magnums I was looking at are steel body so they should be stronger than the factory stamped rockers I'd think. Or is it the needle bearings in the fulcrum that go bad?
I'm looking for something that i'm not going to need to worry about for a few years and hopefully at least 50-75k miles. The engine I'm figuring on being in the 250-ish HP range or so and the car probably won't be seriously raced or see past 5500 RPM on a regular basis.
The reason I want full roller even though it is probably overkill is mostly the reduction in friction and heat generation. Budget will allow for the full roller parts even though the Magnums are a lot cheaper so that isn't an issue.
Will this be an issue for long term street durability? A friend of mine says he's seen a lot of failures in roller rocker arms... but that may just be in the aluminum body ones. The Ultra Pro Magnums I was looking at are steel body so they should be stronger than the factory stamped rockers I'd think. Or is it the needle bearings in the fulcrum that go bad?
I'm looking for something that i'm not going to need to worry about for a few years and hopefully at least 50-75k miles. The engine I'm figuring on being in the 250-ish HP range or so and the car probably won't be seriously raced or see past 5500 RPM on a regular basis.
The reason I want full roller even though it is probably overkill is mostly the reduction in friction and heat generation. Budget will allow for the full roller parts even though the Magnums are a lot cheaper so that isn't an issue.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Full roller rockers should not be a problem. I had a set (not one of the well known brands) with over 70,000 on them without issues. When I first got them I had them on a set of cast iron (original heads) on my 85. I was afraid they might implode ....heard horror stories. I actually took and cut small pieces of wire screen and epoxied them over all the oil return holes in the heads. The screens are still there and the RR are still fine. Moved the heads over to another engine I had so they are no longer on the Corvette.
Burning Brakes
Joined: May 2010
Posts: 900
Likes: 3
From: Cary illinois
I have a set of Stainless Crowers 3/8 stud 1.6 250.00 Firm They have six or seven AX events on them .Still on my original L98 sitting on the engine stand .400 new ,should last you a long long time
Racer
Joined: Jun 2012
Posts: 343
Likes: 9
From: Long Beach Ca,
I don't understand something, are you replacing the cam with a roller cam and why not get a cam with the lift your looking for instead of using 1.6 ratio rockers. Does your engine have a hyd flat tappet cam in it right now. If so then your looking at a retro kit to go full roller. I would by a cam that gives me the lift I want. The 1.6 rockers are good for a little bit extra lift on a stock cam but an aftermarket cam, you shouldn't need it. Roller rockers would give some improvement but remember you get what you pay for. On my 85, I'm going with Ultra Pro Magnum but leaving the rev train.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
I don't understand something, are you replacing the cam with a roller cam and why not get a cam with the lift your looking for instead of using 1.6 ratio rockers. Does your engine have a hyd flat tappet cam in it right now. If so then your looking at a retro kit to go full roller. I would by a cam that gives me the lift I want. The 1.6 rockers are good for a little bit extra lift on a stock cam but an aftermarket cam, you shouldn't need it. Roller rockers would give some improvement but remember you get what you pay for. On my 85, I'm going with Ultra Pro Magnum but leaving the rev train.
Last edited by ddahlgren; Jul 15, 2015 at 12:38 PM.
Thread Starter
Pro
Joined: Dec 2014
Posts: 530
Likes: 10
The higher ratio increases area under the curve without added duration so the best of both worlds more torque and hp and no downside until you go crazy with it and have valve spring issues due to lift and acceleration rates. Do be sure to get the pushrod lengths right too as that affects how long it all lives and any gains you might get.
And yes, the engine is an L83 and currently has a stock profile hydraulic flat tappet cam in it with stock stamped 1.5 ratio rockers so the lifters I will be using will be retrofit type (link bar). I'm planning on a new intake manifold (Renegade) and headers as well as new aluminum heads with 64cc chambers, 180cc intake ports and 2.02" intake valves. The car already has a cat-back system on it. I'm also upgrading the ignition with a Super 65k HEI and 8.8mm Accel plug wires.
The goal is to get this thing up from stock 205 HP to the 250 HP range so it at least is competitive with L98 cars. Intake, cam, heads & exhaust ought to work together to get me around 45 HP improvement.
Last edited by softwarejanitor; Jul 15, 2015 at 01:34 PM.
Burning Brakes
Joined: Jan 2000
Posts: 831
Likes: 31
From: Merritt Island Florida
I would not use a Comp cam. Especially if it was made over a few years ago. They have been failing. The new ones are suppose to be corrected.
Roller rockers are fine. How high do you want to rev the car?
Roller rockers are fine. How high do you want to rev the car?
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Thread Starter
Pro
Joined: Dec 2014
Posts: 530
Likes: 10
It would be a brand new cam... The cam I selected is supposed to produce power between 1800-5400 RPM. I know that full roller valvetrain is probably overkill for a motor that won't regularly see much above that, but I'd like the reduced rolling friction and the corresponding improvements in efficiency and reduction in heat generation, etc.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
Comp Cams spends a lot on marketing, but very few racers use the brand. They sell a lot of junk. I'm partial to Crane.
Intermediate
Joined: May 2015
Posts: 36
Likes: 1
From: Knoxville TN
Have full roller rockers on all my cars, some cheap one and some high priced, never had a failure in the last 30 years. I am an under 6500 rpm guy and a take care of my junk, but I do drive them hard.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 413
From: WV
After lots of reading and asking on here about roller rockers I came to the conclusion that the 2 best rockers to get were either Crane Golds or Scorpion rockers,plus they both have lifetime warrantys..Can't go wrong with either one....
...WW
...WW
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
..WW
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
I have full aluminum body 1.6 roller rockers on my two 406 sbc that I street drive everywhere and race quite often. Each of these cars has over 100,000 miles on the rockers and I have never had a failure. They are the narrow body summit brand rockers.