Lets talk about rocker arms
Lets talk about rocker arms What rocker arms are most of you guys running ?? I've always used the stockers. even on my 3x package making 491 hp to the wheels I was using the stock ones . Now would I see a gain going to the aftermarket ones? Do they still fit under the stock valve covers?? Am I going to see any real hp gain to justify the money spent?
Thanks
Thanks
Its neglegable at that kind or RWHP. you may gain 7 - 10 HP outt it but more than anything you will gain from them if you tend to rev higher than the stock redline. Also they will reduce friction greatly against the valve so you will also be creating a little less heat. You can get a shaft mounted set for 600-800 but if you wanna take the a slightly cheaper route then Harland Sharp makes a great set in the $300 range. They are full roller but still mount on the stock rocker stud.
Those are going to be on of my next mods and from what ive seen, they fit under the stock valve covers!
Those are going to be on of my next mods and from what ive seen, they fit under the stock valve covers!
We did a dyno back to back with the stockers and first pull was a gain of 8rwhp the next 2 were gains of 10rwhp. They are about 10 ounces lighter than the stocks and it does rev faster. They also fit under the stck valve covers but the 98`s requier some clearancing...I do assume you are no longer running 98 heads though making 491rwhp. I would love to see that car make 500 that would be pretty cool. I sell the Harland Sharps for $320.00 I should have these back in stock some time this week if you are interested.
Nate
Nate
I have always used Comp Cams Pro Magnum Roller Rockers. This will be my first set on an LS1, but I used them on the last three small block chevy engines that I built. Quality, durability, & precision. They will give you all of that.
They will Comp is an excellant company. But why would you take your technolgicly advanced motor back to pushrod guild plates? Also there is no sence in having adjustable rockers unless you are running a solid cam...unless you wish to adjust the valve train every couple thousand miles for fun. I would definatly use the Comps for a solid roller setup.
Nate
Nate
Originally Posted by Nasty N8
They will Comp is an excellant company. But why would you take your technolgicly advanced motor back to pushrod guild plates? Also there is no sence in having adjustable rockers unless you are running a solid cam...unless you wish to adjust the valve train every couple thousand miles for fun. I would definatly use the Comps for a solid roller setup.
Nate
Nate
When you set hydraulic lifters right you don't have to adjust them again. I have been building engines for 20 years and there is no way I want non- adjustable rockers on a modified engine.
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Joined: Nov 2001
Posts: 1,248
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From: Kansas City, MO
Originally Posted by Colonel
Stock works fine for me. I don't buy the "I gained XX RWHP from just swapping rockers" stories if we're talking about keeping the same ratio.
Stocks have worked fine for most including me but I have changed out 14 sets of the factory rockers that spit there bearings out. I don`t want that in my 500hp motor.
The Harlands are lighter have less friction and are considerably more stable than the stocks. And when we did a back to back dyno test on the Harlands and stocks we gained 8-10 rwhp. That is enough to help anyone out.
Oh and I never said adjustables were old tech I said guild plates were.
Nate
The Harlands are lighter have less friction and are considerably more stable than the stocks. And when we did a back to back dyno test on the Harlands and stocks we gained 8-10 rwhp. That is enough to help anyone out.
Oh and I never said adjustables were old tech I said guild plates were.
Nate
Originally Posted by DenzSS
Yup. fractional gains attributable to any number of variables.
So if the aftermarket dont flex (same ratio as stock) you will get more lift out of your cam.
Just what I have heard
TECH Fanatic
Joined: Nov 2001
Posts: 1,248
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From: Kansas City, MO
Originally Posted by DEEZ98Z
I was told before that most of the gains that you get with aftermarket rockers is due to the lack of flex in them. The stock rr's supposivly flex which will give you less lift.
So if the aftermarket dont flex (same ratio as stock) you will get more lift out of your cam.
Just what I have heard
So if the aftermarket dont flex (same ratio as stock) you will get more lift out of your cam.
Just what I have heard
Factory rocker failure is incredibly uncommon. In general, it is another one of the unrealistic fears placed into people by the internet. I would contribute most stock rocker failures to poor cam design. Some of the lobes people are trying to run with hydraulic lifters are incredibly silly for cars that get driven frequently. When you have to get exotic on your lifters and rockers with a hydraulic lifter daily car, you really need to stop and think about what you're doing.
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Joined: Nov 2001
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From: Kansas City, MO
Another quick point. 8-10rwhp is well within the range of variations caused by coolant and oil temp. Not to mention any other number of variables, both known and unknown. We're talking about a +/- 3% margin on a 350rwhp car on the average dyno. Most dynos are not capable of that precise of a measurement.
After installing the 1.8 HS rockers (thanks Nate!) and LS6 springs, my car gained 1mph at the track (was 107-108, now at 108-109, 2 weeks apart, same track, similar weather conditions). I need slicks now so I do not have a good gage of any et improvement yet. I plan to dyno this weekend to see if it gained any hp. The engine sounds better...quieter. And seems to rpm a little quicker.
As for the fit, the 1.7s fit fine on my buddies SS, even with shims. My 1.8s fit fine until I had to shim them. Then the valve covers needed modding.
As for the fit, the 1.7s fit fine on my buddies SS, even with shims. My 1.8s fit fine until I had to shim them. Then the valve covers needed modding.
I am running non/adjust 1.7 Y/T's at .010 preload for my Comp R lifters.
I went with aftermarket since my car will repeatedly see 6900-7200 rpms for the next two years, and I don't see the stock stamped rocker arms as being as strong. And I think that the stockers will have more deflection.
I went with aftermarket since my car will repeatedly see 6900-7200 rpms for the next two years, and I don't see the stock stamped rocker arms as being as strong. And I think that the stockers will have more deflection.
i got the HS rockers, not for the gains but for the reliability, taking a look at them you can clearly see they are built better than the stockers.... so if nothing i think the rockers are more for piece of mind rather than hp
jimmy
btw, since i swapped them, the engine revs faster
jimmy
btw, since i swapped them, the engine revs faster
TECH Senior Member
Joined: Nov 2001
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From: Troy, AL
"I have changed out 14 sets of the factory rockers that spit there bearings out."
Just curious, but were any of these '01+? And could valvefloat have been a factor?
I agree that a little flex will cost you a little lift but really...how much power are you going to gain from a couple thousandths lift? You can't dyno that. As for frictional losses, look what we're starting with. If there were 10 or even 5 HP worth of friction then you would see tremendous wear in a short amount of time...but yet we normally see virtually NO wear in these valvetrains even after 100K+ miles. Think about the kind of heat that would be caused by the friction required to draw 5 RWHP. Picture the power made by a 5 HP go-cart motor. 5 HP is alot more energy (and heat) than we commonly think of. That's ALOT of heat, thus ALOT of friction, thus ALOT of wear that simply isn't there by any stretch of the imagination.
You can see 1-2 MPH difference two weeks apart in seemingly identical weather with seemingly NO changes to the car. I've seen it with my own cars and other's too many times. That is all too common. You can also see 5-10 RWHP difference in dyno numbers just between the 1st-2nd-and then 3rd pulls on a chassis dyno with NO changes made. Testing has to be done VERY carefully and repeatedly to confirm 5 RWHP gains.
I am convinced that to see measurable power gains by simply swapping rocker arms (keeping the same ratio mind you) that you would have to have some SERIOUS deflection taking place to begin with causing significant lift losses...and that's just not the case or you would see arms structurally failing which I've yet to hear of.
Just curious, but were any of these '01+? And could valvefloat have been a factor?
I agree that a little flex will cost you a little lift but really...how much power are you going to gain from a couple thousandths lift? You can't dyno that. As for frictional losses, look what we're starting with. If there were 10 or even 5 HP worth of friction then you would see tremendous wear in a short amount of time...but yet we normally see virtually NO wear in these valvetrains even after 100K+ miles. Think about the kind of heat that would be caused by the friction required to draw 5 RWHP. Picture the power made by a 5 HP go-cart motor. 5 HP is alot more energy (and heat) than we commonly think of. That's ALOT of heat, thus ALOT of friction, thus ALOT of wear that simply isn't there by any stretch of the imagination.
You can see 1-2 MPH difference two weeks apart in seemingly identical weather with seemingly NO changes to the car. I've seen it with my own cars and other's too many times. That is all too common. You can also see 5-10 RWHP difference in dyno numbers just between the 1st-2nd-and then 3rd pulls on a chassis dyno with NO changes made. Testing has to be done VERY carefully and repeatedly to confirm 5 RWHP gains.
I am convinced that to see measurable power gains by simply swapping rocker arms (keeping the same ratio mind you) that you would have to have some SERIOUS deflection taking place to begin with causing significant lift losses...and that's just not the case or you would see arms structurally failing which I've yet to hear of.