Roller tip rockers are they worth it?
#1
Roller tip rockers are they worth it?
On a 1984 corvette is it worth it to go to the effort to install roller tip rockers on the crossfire engine? If it is worth it which ones fit under the stock valve covers? How much hp gain is it if any?
#2
Race Director
If you don't change the rocker arm ratio there will be no horsepower gain. I have heard that the oil temperature will be lower because of less friction between the rocker arm and the valve stem.
I have the Comp Cams steel roller tip rocker arms on my car.
I have the Comp Cams steel roller tip rocker arms on my car.
#4
Burning Brakes
I have the Comp Cams roller tip 1,6 , gain - yes ! they are bolt on under stock valve covers
#5
Le Mans Master
I would suggest that you go with the full rocker, not just the roller tip.The heat is generated between the pressed rocker and the half ball that goes under the stud nut. Yes there are groves in the ball to oil this area. When I installed the full rocker my oil temperature dropped 8-9 degrees. The pressed rockers you have on there now are supposed to be a 1:5 ratio but when measured usually run 1:45 +/_. The 84 might be like my 85 and idle better with a split ratio of 1:5 and 1:6. The 1:6 on the exhaust valves. You will see a 5-7 gain in HP. You can find several manufactures that make the split ratio.
You will have to cut off the drip tabs under the VC and might need to go to a taller VC gasket.
You will have to cut off the drip tabs under the VC and might need to go to a taller VC gasket.
#6
Safety Car
The roller tips gain performance over the stamped steel units. As mentioned previously, the oem ones are more like 1.45 or 1.47 ratio and the roller tips (at least Comp Cams brand) are 1.52 to 1 ratio.
I put a set on a 305 L98 on a 5 speed camaro and I could totally feel the extra pop. That said, a stamped steel, non-roller 1.6 could make more power than a 1.5 full roller just due to the cam function. I do not trust fancy rocker arms on a street engine. If you aren't endurance racing, why spend the money? A 5500 rpm smallblock? I don't think so. Roller tip units are proven to be reliable and not too expensive. Look how much trouble GM had with the LT4 roller rocker recall... if I had to do it, I'd probably buy Crower shaft mounted ones, but I think you might need the tall valve covers.
I put a set on a 305 L98 on a 5 speed camaro and I could totally feel the extra pop. That said, a stamped steel, non-roller 1.6 could make more power than a 1.5 full roller just due to the cam function. I do not trust fancy rocker arms on a street engine. If you aren't endurance racing, why spend the money? A 5500 rpm smallblock? I don't think so. Roller tip units are proven to be reliable and not too expensive. Look how much trouble GM had with the LT4 roller rocker recall... if I had to do it, I'd probably buy Crower shaft mounted ones, but I think you might need the tall valve covers.
#7
Melting Slicks
if you're on a budget...or even if you aren't...roller tip rockers have a definite advantage. The roller ROLLS across the valve stem tip and doesn't impart a side load on the valve stem = (much) less wear on the valve guides. Do it
#8
#9
Burning Brakes
http://www.ebay.com/itm/Chevy-265-283-302-305-327-350-400-Comp-Cams-Magnum-Roller-Rockers-Arms-3-8-1-6-/150782152924?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item231b5110dc pics in my crossfire album https://www.corvetteforum.com/g/picture/1347320
Last edited by corvettenorway; 10-12-2014 at 02:14 PM.
#11
Burning Brakes
#12
Do they fit under the stock valve covers without hitting? What valve cover seals did you get? I see in ebay you can get a whole kit with pushrods for a bit more money?
#13
Burning Brakes
Do they fit under the stock valve covers without hitting = yes ! valve cover seals =stock ! go get the set / with pushrods !
#14
#15
Burning Brakes
tigten to you can feel it turning the pushrods , then 1/2 turn
#16
Le Mans Master
Tightening roller rockers, or roller tip rockers down is the easy part, you have to check to make sure the rockers aren't making contact with the spring cap or spring, or they can self destruct in minites after startup, there should be a minimum of 0.040 between the rocker and spring cap....You also have to make sure the roller is dead center on the valve tip so you get a straight line drive from the rocker,If it's not in the center the push rods may need to be changed,, if it's off one way or the other you will get excessive premature valve guide wear because the push rod isn't being pushed straight down.....There's a lot more to installing aftermarket rockers then just pulling the old ones off , and bolting the new ones on..For the top end to last, the geometry has to be perfect.....WW
Last edited by WW7; 10-12-2014 at 08:41 PM.
#18
you know on the subject.. the 84 heads (assuming you still have a 84 with stock heads) don't have open pushrod area, it has just small guides that i believe would act the same as having guide plates.
#19
Safety Car
You can run non-self aligning rockers on a roller cam engine for about 2-3 years (with a stock cam), but eventually the valve stem scrub will wear down to the retainer and all hell will break loose when the valve drops down into the cylinder. (ask me how I know).
#20
Race Director
Member Since: Dec 2002
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Here are some of my thoughts:
The power that is gained from going to 1.45 to a 1.52 rocker arm ratio will barely be measurable. It certainly cannot be felt by the driver. I had a set of Comp Cams roller tip rockers installed in my built 400 cu. in. smallblock years ago. Two of the roller tips seized at about 8500 miles. Replaced all the roller tips with stock rockers; engine ran the same.
95% of the friction in a stock (stamped steel) rocker comes from the fulcrum. The tip contributes almost nothing. Go full rollers...steel or aluminum...for any benefit. Stamped steel with roller tips are a waste of money.
I now have nearly 100K miles on my LT4. The aluminum roller rockers have given no problems. If a component is acceptable for endurance racing, it will have no problem giving good service on a street engine. Endurance racing is the ultimate test of engines.