lets talk roller rockers

[RootBreaker]

Ok so I went with a smaller cam than I wanted to but so far am pleased. I was talking to someone and they told me to put roller rockers on.. this will free up hp as less friction...

my questions...
if you go from 1.5 rockers to 1.6 rockers.. how much does that affect cam lift?
I was told for the 1.5 to 1.6 = .03" lift on a cam.. so my .454" lift cam is now a .484" lift..... sound right?

also how much more strain is placed on the heads as stock vortecs are supposedly good to .480" lift per summitracing?

will the bigger roller rockers change the power band too? I went with my cam as it was a idle to 5k power range.. the cam above it was 1200-5500rpms.... so bigger roller rockers does the same thing?

i will most likely go with 1.5 roller rockers but want to look at my options

 

[dyeager535]

I will address the spring issue, that should have a [retty strong beaing on your decision.

Did you measure the clearance of the retainer at full lift? I made a valve spring out of an extremely light spring found at a hardware store, so that I could actuate the valve without compressing the hydraulic lifter.

Anyways, with my cam (.452" max) I was so close to hitting at max lift, that I was borderline whether I could use the cam. I have less clearance than is recommended, but since the motor isn't high revving I didn't expect to run into contact issues. I've read the measurement before, as I recall it was right around the thickness of a penny to clear...I couldn't fit a penny in there at max lift.

I've seen varying Vortec cam lift numbers, but they were all under .430" IIRC. The setup wasn't designed to clear more lift.

What cam did you end up running? Did you get springs matched up? Crane told me that stock Vortec spring seat pressure isn't enough, and made sure I understood that.

I KNOW that there are varying reports as to how much lift you can safely run on Vortecs, but I also know exactly what mine were. Not saying there aren't differences in castings, just that I would never consider just slapping something in to increase lift not knowing if they will clear.

The results from roller rocker installs don't seem to be that much, maybe 5HP. "Free" power is free power, but for the cost, if you don't NEED them, it may not be worth the hassle. Just my opinion. Nice to have, but a set of really nice rockers is going to run you what, $100-150?

 

[SUBFAN]

"Really Nice" roller rockers will be more in the $400 range....

Your cam math is correct. A 1.6 rocker will appear to have a .484" lift, only if the cam lift given is with a 1.5 rocker. (Most likely the case.)

Take the lobe lift off the cam card and multiply by 1.6....If all you have to go by is a lift with 1.5 rockers, then divide that number by 1.5, and multiply the answer by 1.6....

 

[dyeager535]

I guess I didn't pay anywhere near that, but looking at prices online for what I've got (SBChevy V8 Hi-Tech Steel Rockers - 3/8, 1.5 Ratio) I can see that good roller rockers are really expensive, and I got a great deal.

 

[neverendingproject]

also how much more strain is placed on the heads as stock vortecs are supposedly good to .480" lift per summitracing?

will the bigger roller rockers change the power band too? I went with my cam as it was a idle to 5k power range.. the cam above it was 1200-5500rpms.... so bigger roller rockers does the same thing?

The high lift doesnt put any strain on the heads, its the fact that the new seal design they used ont the vortecs will only allow so much travel before the valve bottoms out on the head. A 1.6 rocker is just just a bit more "dramatic" than a 1.5 rocker. If you think about it its really simple. The 1.6 has more lift to go to, so it will open up faster than a 1.5. And because it is more "dramatic" it will start to open sooner. All In all I think it moves your powerband up 100 rmps or so if used on the intake. I personally used 1.5 on my intake side and used 1.6 on the exhaust side to increase scavenging effect.

note*: If you are using 1.6 rockers on your vortec, aside from the lift issue, you must also enlarge you pushrod hole to accept a smaller swing, because the 1.6 rockers bring the pushrod in closer.

 

[beastofablaze]

roller rockers only free up hp at very high rpm and it'll only be about 20 or less. might want to consider spending that 400 on on some better upgrades. I don't know your rigs specs but vortec's will run about 500.

A NOS setup... etc.

I am not saying these are the best mods to do... just to lazy to use my brain and uh... ...... ..... ..... oh yeah, think.