Upgrade Rocker Arm
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
Likes: 26
From: Lexington Park Maryland
Upgrade Rocker Arm
It's been s while, but I remember an episode on "Horse Power" TV show. They replaced the stock stamped rocker arm with a roller type alluminum version, it was even mentioned about some hp gain. Has anyone done the same upgrade? Where did you get them and which did you use? thank you.
Race Director
Joined: May 2006
Posts: 18,737
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based on various sources, not just the cam manufacturers, the stamped steel production arms appear to have only about a 1.37 ratio as opposed to the specified 1.5 ratio. So switching to something like the Competition Cams roller tip rockers at 1.52 or 1.6 ratio may provide a minimal improvement without having to go to full rollers.
1.37 ratio article http://www.crankshaftcoalition.com/w...cam_adjust.pdf
http://www.summitracing.com/parts/cca-1412-16/overview/
1.37 ratio article http://www.crankshaftcoalition.com/w...cam_adjust.pdf
http://www.summitracing.com/parts/cca-1412-16/overview/
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
If you want roller rockers no sense going half-way with them. Might as well get the full roller type for the about the same money.
http://www.summitracing.com/int/part...1-16/overview/
http://www.summitracing.com/int/part...1-16/overview/
Instructor
Joined: Jul 2012
Posts: 110
Likes: 2
Roller rocker
Hot Rod mag. did an story on hopping up chevys ZZ5
Stock vs. roller was worth 11.2hp. and 4.6 lb-ft. 1.5 to 1.5
1.5 to 1.6, 18.9 hp, 7.8 lb-ft
Hot Rod April 2016
Don't over look cooler oil temp and less friction.
Stock vs. roller was worth 11.2hp. and 4.6 lb-ft. 1.5 to 1.5
1.5 to 1.6, 18.9 hp, 7.8 lb-ft
Hot Rod April 2016
Don't over look cooler oil temp and less friction.
Last edited by GBC; Feb 18, 2016 at 03:49 PM. Reason: more info
Drifting
Joined: Aug 2006
Posts: 1,729
Likes: 193
From: Scottsdale Arizona
I am planning on new heads and 1:6 roller rockers and I found this article.
http://www.hotrod.com/how-to/engine/...er-ratio-test/
http://www.hotrod.com/how-to/engine/...er-ratio-test/
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Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
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From: Lexington Park Maryland
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
In the 60's and 70's many times we discovered that switching to a performance cam in SB Chevy's and Ford's with stock stamped steel rockers would result in occasionally snapping of rocker studs. We would elongate the slots a bit with a dremel or other grinding point to eliminate this problem.
In the late 70's I built up a 302 Ford for a Mustang I had. I used a Crane Fireball hydraulic cam and periodically would snap one of the rocker studs. I made a fixture that allowed me to measure the slot in all of my rockers. What I discovered was that the slots varied by as much as 10 degrees. I then opened the rocker with the longest slot 5 degrees on each end and matched the remainder of the slots to that one. Never broke a stud again.
Quality roller rockers, along with having a more precise ratio and somewhat less friction, also allow more slot angle that the typical stock stamped steel rockers.
Good luck... GUSTO
In the late 70's I built up a 302 Ford for a Mustang I had. I used a Crane Fireball hydraulic cam and periodically would snap one of the rocker studs. I made a fixture that allowed me to measure the slot in all of my rockers. What I discovered was that the slots varied by as much as 10 degrees. I then opened the rocker with the longest slot 5 degrees on each end and matched the remainder of the slots to that one. Never broke a stud again.
Quality roller rockers, along with having a more precise ratio and somewhat less friction, also allow more slot angle that the typical stock stamped steel rockers.
Good luck... GUSTO
Safety Car
Joined: Sep 2005
Posts: 4,226
Likes: 643
From: Orange County Ca
You can switch from stock factory (nominal 1.5 ratio) to 1.6 ratio, long slot rockers and gain a little on your cam as long as you have enough room that your valve springs don't bind up. Roller trunion rockers will reduce friction a little but you won't notice any difference. Roller tip rockers are a total waste of money. 430 hp LS3 (c6 corvette) hare roller trunions but not roller tips. Roller tips have been shown to just slide over the top of the valve stem, not roll. I originally thought that they would spin, but now believe that they don't.
The stock rockers may or may not have different ratios. Who do you believe? Chevy or the after market crowd that wants your money?
If anything, going to the 1.6 would be the most cost effective for a minimal hp gain on a stock engine.
The stock rockers may or may not have different ratios. Who do you believe? Chevy or the after market crowd that wants your money?
If anything, going to the 1.6 would be the most cost effective for a minimal hp gain on a stock engine.
Racer
Joined: Nov 2006
Posts: 264
Likes: 0
From: McLouth Kansas
I have Hdy roller lifters with a roller cam and rockers on a balanced motor and I love them. And there was no need to break in the cam when the engine was first started, instead I just took off down the road and gave her hell to break in the rings.
Last edited by Racer11; Feb 23, 2016 at 10:23 PM.
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
Likes: 26
From: Lexington Park Maryland
I should received the new set of rockers (1.6:1) anyday now, what I wanted to know if I can use the stock push rods or do I need to get a new set. the stock are in great shape, I did not noticed and major wear pattern on them. Thank you.
Drifting
Joined: May 2005
Posts: 1,968
Likes: 44
From: East TN
World Products iron 64cc heads 2.02 intake 1.60 exhaust valves 200cc intake runners with Crane Gold Series aluminum rockers 1.52 ratio on a 385 stroker. I think most of the parts were bought from Summit Racing.
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
When I built mine, I went with a huge Roller Cam so naturally I went with Full Roller Rockers .. I chose SCORPION .. little more $$, but MADE IN USA right here in Florida and . Lifetime free replacement warranty. Had them since 09 , I regularly spin 6800 rpm , with .578 lift cam .. no issues. . LOVE THEM .. You will need tall covers
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
The bump in compression and 1.6 ratio roller rockers will wake the car up nicely. Just keep an eye on the rocker studs if they are the pressed in style. They sometimes will start pulling out and you now this by the amount of threads sticking up about the rocker nut or is using poly locks, it will be the rocker that needs adjusting tighter often. I don't think you'll have a problem with stock springs and cam but just be aware.
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
based on various sources, not just the cam manufacturers, the stamped steel production arms appear to have only about a 1.37 ratio as opposed to the specified 1.5 ratio. So switching to something like the Competition Cams roller tip rockers at 1.52 or 1.6 ratio may provide a minimal improvement without having to go to full rollers.
1.37 ratio article http://www.crankshaftcoalition.com/w...cam_adjust.pdf
http://www.summitracing.com/parts/cca-1412-16/overview/
1.37 ratio article http://www.crankshaftcoalition.com/w...cam_adjust.pdf
http://www.summitracing.com/parts/cca-1412-16/overview/
An important issue to understand is that no shaft mounted or ball and socket rocker arm will have a constant ratio. The 1.37:1 ratio is at the lash point and I used this value to develop more refined lash recommendations for mechanical lifter cams where the height of the clearance ramp can be measured or analyzed from the engineering drawing lobe lift data.
The maximum OE rocker ratio is about 1.44:1 with about a 0.3" lobe height.
Whatever the advertised rocker ratio, it's not constant, so you have to take it with a grain of salt and do your own measurements.
Duke
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
I run full RR's under stock valve covers... what I do is run a 1/2" aluminum space between the valve cover and heads... you can get the spacers an eBay very reasonably...
Last edited by pauldana; Mar 16, 2016 at 01:03 PM.
Had a 1976 L-82, 4-sp
Joined: Mar 2011
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy