The 402 I'm working on has aluminum roller and roller tip rockers. I read in a How To book that for big blocks, roller rockers aren't really recommended because they don't allow as much oil flow to the pushrod.
I'm considering putting stock stamped rockers in for a few reasons:
1. Reliability and repair-
The stockers worked fine back in the day for 400 HP or more, so why have more complexity? If I do ever break down somewhere away from home, I can go to the corner O'Reilly's and pick up new parts.
2. I could go back to stock height valve covers
There are tall valve covers on it now that barely fit under the brake booster and AC box
3. I believe that the roller rockers only add 5 HP or so and at that on the high rpm end
I'm redoing this motor to be strong on the street but reliable. Not looking for a high rpm strip screamer. It would add about $150 to the budget, but again would be more about insurance/reliability and knowing what is in the engine than anything else.
Any thoughts one way or another?
Derek69SS said
Jan 9, 2011
Are the rockers in it now a good quality brand, or are they cheap "Proform" rockers? If they're the cheapies, they WILL give you trouble in the future. If they're good ones, I'd probably keep them.
I'm not much of an "engine" guy though.
SShink said
Jan 9, 2011
I think they are more on the 'Proform' end of things. They do look a lot like some Crane rockers, but I'm not sure. Chris R. found a Crane pic that looks a lot like them. I attached the pic.
If they're Crane (or another "reputable" mfg.) they should have a part number or logo on them... If they're a knock-off ???
I think most know my stand on aftermarket vs. OEM parts. If it's a mild performance, sunny-day cruiser that might see an occasional flogging - go OEM. There isn't an aftermarket manufacturer that has the quantity of units, the engineering bucks, or the resources to match GM.
If the parts work on hundreds of thousands of engines (within the design specs) why change to "Long Duck Dong's Hi-Perf Engine Doodads ".
If you do go "stock/OEM" get the rockers that have the grooved pivot balls. They really help reduce the galling in the pivot socket.
You could probably swap even up for a new set of stockers and valve covers on Craig's List in a week.
Dave Seitz said
Jan 9, 2011
I have the Scorpion 1.6 roller rocker and found out after I got them this little info.
1. The Scorpion RRs have 2 that are special profile to fit under stock valve covers.
2. They can be sent back to MFG for rebuilding and inspection.
Folks say they are some of the better ones as well so I got lucky getting them.
dashboard said
Jan 9, 2011
Stamped GM rockers equate to less moving parts. Fewer moving parts equates greater reliability. But there I go again spending your money.
""If they're Crane (or another "reputable" mfg.) they should have a part number or logo on them... If they're a knock-off ???""
Once again John's right.
67ss said
Jan 9, 2011
I would keep them, stock big block rockers are prone to breaking. Adding more lift and higher spring pressures only makes it worse. If you do go back to stock make sure to buy long slot replacments to handle the lift of the aftermarket cam.
Let me know if you take them off I would probably buy them to put on the 396 I am building for my buddies 69 chevelle.
Chris R said
Jan 9, 2011
I would keep them. Roller rockers have less friction when they function and is easier on valvetrain parts. To be sure though, I would ask the engine builder what he thinks.
Bungy L-76 said
Jan 10, 2011
What Chris said. The rollers will put less strain on the tops of the valves then the stock stamped rockers. the rollers will "roll" across the tops of the valves where as the stockers will "push" and "pull" the tops of the valves increasing valve guide wear. That's one of the main advantages of rollers. As well as the reduced friction and increased horsepower.
"roller rockers aren't really recommended because they don't allow as much oil flow to the pushrod."
I don't understand this statement. The oil comes thru the pushrod first before it gets to the rockers.
SShink said
Jan 10, 2011
Thanks everyone for the feedback.
I think Chris R. is right, I'll take a roller rocker to Comp Engines and see what he recommends.
Chris R said
Jan 10, 2011
Those are a nice set of rockers. They looked exactly like the Crane ones. I thought Crane put thier logo on stuff like that but I guess not. If it were me, I would be more inclined to re-use them instead of going with stock, stamped ones. You already have performance parts on your engine. If it were just plain stock, I would then consider the stock arms.
I would be more curious if your engine builder recognizes the rockers and can tell you if they are indeed Crane units or a wanabe look alike from China.
4-door Chevelle said
Jan 11, 2011
I had D&G go through my heads last year. They had a set of good used Comp 1.6 roller rockers that I went with. I will just add my agreement to the statemenst here that say there is less friction and if you have any serious lift at all in your cam stay roller.
Bowtieman427 said
Jan 27, 2011
I know I am chiming in late, but what are you running for a cam lift , duration, type ? What RPM are you turning ?
I have the roller tip steel rockers in 427 Vette running Comp 268H (which sucks for the heads I have) the Comp steel roller tip rockers are working fine. Not sure if they really add that much over stock anything to my setup. I think they have there place if you are turning high RPM. Like the fact that they are steel vs Aluminum. Not prone to metal fatigue.
SShink said
Jan 27, 2011
Bowtieman427 wrote:
I know I am chiming in late, but what are you running for a cam lift , duration, type ? What RPM are you turning ? I have the roller tip steel rockers in 427 Vette running Comp 268H (which sucks for the heads I have) the Comp steel roller tip rockers are working fine. Not sure if they really add that much over stock anything to my setup. I think they have there place if you are turning high RPM. Like the fact that they are steel vs Aluminum. Not prone to metal fatigue.
Hey Jim. I attached a pic of the cam card with the specs. I don't plan on taking this engine over 5500 rpm and will mostly be street driven so I'm trying to keep it mild.
I talked to my engine guy at Competition Engines, and he said either style would work fine and that the rollers help on the higher rpm's (as you said) but the stock ones wouldn't hold this engine back.
So, I decided to go with the stock ones. I will also be able to use the stock height valve covers this way for more clearance under the brake booster and AC box. I've picked up a pair of original GM ones that have the drip rails.
-- Edited by SShink on Thursday 27th of January 2011 08:56:53 PM
Yes stock ones are probably the better choice for your app. Plus they are stamped steel no fatigue or cracking issue take up less area then Aluminm.
The ones you have pictured look pretty serious (all roller). The ones I have on the Vetter are roller tip only no roller not the fulcrum and are alos steel Fit under stock covers. Given your RPM and Hydrolic cam with a relativly mild ramp, mild lift the stock ones will work reliabley well.
I hear you about the stock valve covers some day I want to go Hydrulic roller in the Vette and have a set of Steel full roller ones waiting I am hoping to run with stock covers if and when that day ever happpens.
Very nice with original valve cover find.
Chris R said
Jan 27, 2011
Those rockers you have arent roller tip. Those are full roller rockers. You can always try them both and if you dont like one set. You can switch to the other. I still like the idea of using the full rockers. Although, I forgot about this little detail. If you have short valve covers, the rollers will not fit underneath.
SShink said
Jan 28, 2011
Chris R wrote:
Those rockers you have arent roller tip. Those are full roller rockers. You can always try them both and if you dont like one set. You can switch to the other. I still like the idea of using the full rockers. Although, I forgot about this little detail. If you have short valve covers, the rollers will not fit underneath.
Rollers are already sold. Gotta' sell parts to buy parts. That's the deal with the wife!
Lost in the 60s said
Jan 28, 2011
SShink wrote:Rollers are already sold. Gotta' sell parts to buy parts. That's the deal with the wife! I made the same agreement with mine some time ago but she forgot to stipulate the sale income matching the purchase outgoing... I'm many ten's of thousands behind on selling income right now and keep telling her it will even out "someday". It's all in the fine print...
SShink said
Jan 28, 2011
Lost in the 60s wrote:
SShink wrote:Rollers are already sold. Gotta' sell parts to buy parts. That's the deal with the wife! I made the same agreement with mine some time ago but she forgot to stipulate the sale income matching the purchase outgoing... I'm many ten's of thousands behind on selling income right now and keep telling her it will even out "someday". It's all in the fine print...
I'm with you there man! Although, a couple of trips with the wife to the 'premium' outlet mall will even things up quickly!
Tony Hoffer said
Jan 28, 2011
The main thing with stamped vs a roller rocker is that the slots in the bottom of the stamped rockers often were not long enough for even a moderate lift cam.. ( Im talking from SBC experience here).. I like the roller rockers because you eliminate this problem as well as gaining a more stable geometry at higher rpms and also reduced friction.. Its also been shown in many cases that the roller tip doesnt actually roll across the valve head at all but mostly slides.
Bungy L-76 said
Jan 28, 2011
I never thought about that. With .513 lift, you might want to check the clearance between the stock rocker arm slot and the rocker arm stud. I'm not sure what the clearance is supposed to be, but I'm thinking about .060" minimum at full lift? I remember seeing a pic in some mag of a guy using a paper clip as a guage.
SShink said
Jan 28, 2011
All good thoughts guys. I showed Comp Engines the stamped rocker arm (came from an early 70's 375 hp 396) and he said it would work fine as they appear to have slightly longer slots than a 'normal' stock rocker arm. He's the one that picked out the cam and sold it to me too, so I think he would have caught it if they wouldn't be happy together.
I'm going to put the top end of the engine on this weekend, so I'll watch this area carefully.
SShink said
Jan 28, 2011
I figured out that this is a Melling cam by searching on the pn. Here's the description from their website for this series:
CLASS II (215° - 230°) Fair idle quality. Good low to mid range torque and horsepower. Will work with stock or modified engine. Manual or auto transmission. Possibly lower vacuum than stock.
I'm considering putting stock stamped rockers in for a few reasons:
1. Reliability and repair-
The stockers worked fine back in the day for 400 HP or more, so why have more complexity? If I do ever break down somewhere away from home, I can go to the corner O'Reilly's and pick up new parts.
2. I could go back to stock height valve covers
There are tall valve covers on it now that barely fit under the brake booster and AC box
3. I believe that the roller rockers only add 5 HP or so and at that on the high rpm end
I'm redoing this motor to be strong on the street but reliable. Not looking for a high rpm strip screamer. It would add about $150 to the budget, but again would be more about insurance/reliability and knowing what is in the engine than anything else.
Any thoughts one way or another?
I think most know my stand on aftermarket vs. OEM parts. If it's a mild performance, sunny-day cruiser that might see an occasional flogging - go OEM. There isn't an aftermarket manufacturer that has the quantity of units, the engineering bucks, or the resources to match GM.
If the parts work on hundreds of thousands of engines (within the design specs) why change to "Long Duck Dong's Hi-Perf Engine Doodads ".
If you do go "stock/OEM" get the rockers that have the grooved pivot balls. They really help reduce the galling in the pivot socket.
You could probably swap even up for a new set of stockers and valve covers on Craig's List in a week.
""If they're Crane (or another "reputable" mfg.) they should have a part number or logo on them... If they're a knock-off ???""
Once again John's right.
I would keep them, stock big block rockers are prone to breaking. Adding more lift and higher spring pressures only makes it worse. If you do go back to stock make sure to buy long slot replacments to handle the lift of the aftermarket cam.
Let me know if you take them off I would probably buy them to put on the 396 I am building for my buddies 69 chevelle.
"roller rockers aren't really recommended because they don't allow as much oil flow to the pushrod."
I don't understand this statement. The oil comes thru the pushrod first before it gets to the rockers.
I think Chris R. is right, I'll take a roller rocker to Comp Engines and see what he recommends.
I would be more curious if your engine builder recognizes the rockers and can tell you if they are indeed Crane units or a wanabe look alike from China.
I talked to my engine guy at Competition Engines, and he said either style would work fine and that the rollers help on the higher rpm's (as you said) but the stock ones wouldn't hold this engine back.
So, I decided to go with the stock ones. I will also be able to use the stock height valve covers this way for more clearance under the brake booster and AC box. I've picked up a pair of original GM ones that have the drip rails.
-- Edited by SShink on Thursday 27th of January 2011 08:56:53 PM
I like the roller rockers because you eliminate this problem as well as gaining a more stable geometry at higher rpms and also reduced friction.. Its also been shown in many cases that the roller tip doesnt actually roll across the valve head at all but mostly slides.
I'm not sure what the clearance is supposed to be, but I'm thinking about .060" minimum at full lift? I remember seeing a pic in some mag of a guy using a paper clip as a guage.
I'm going to put the top end of the engine on this weekend, so I'll watch this area carefully.
CLASS II (215° - 230°)
Fair idle quality. Good low to mid range torque and horsepower. Will work with stock or modified engine. Manual or auto transmission. Possibly lower vacuum than stock.