^^^^This is EXACTLY how it is computed. Always go back to cam lift (.353 here),then multiply with the new ratio.

 

No it's not. 1.7 times 1.1(10%more) is 1.87. Dividing 1.8 by 1.1 is 1.636. It is NOT a 10% difference

 

 

I like roller rockers. Using the right spring you can negate the added weight. For a heavy vehicle they seem to add good low- midrange gains.

 

plus at low lift, stock rockers are more like 1.5. They have a progressive ratio due to that curved pad. The higher the lift, the higher the ratio. Rollers are much closer to true 1.7 the entire time.

 

Not to be mean; but some people should have paid more attention in grade school arithmetic.

This is NOT "10% more". It is .1 ÷ 1.7 more; which is about 5.882% more.

.600" × 1.05882 = .635", the same result as the route that 01 & GAtsma's more common calculation method produces. That's the nice thing about numbers... if you work the problem right, the answer has no choice BUT to be right.

 

Can you post a link for this info. Interesting for sure.

 

It's in a bunch of Comp's literature. I guess it takes that much less metal to hold the tip axle if it's going through stainless, than through aluminum. I think Crower might say the same thing about theirs, not sure. Both companies' design has the tip "relieved" behind the roller, with holes through it.

 

Ive read the literature. I’ve never seen anything in their info about weight. Hoping you’d post it up, cause I missed it.

 

I'll look around for it. I've definitely seen it.

 

If I recall, I didn't find it on their website or anything, I got this info from talking to two different Tech Help folks at Comp. It was also supported by discussions here at LS1Tech and one of the Corvette forums. If I can find those threads again I'll post links. But take a look at the physical structure of the Pro Magnums, it isn't hard to believe. Though they are made of chromoly steel, the tip is narrower and made of webbing not solid steel unlike aluminum rockers which have very bulky tips. Also the massive size of the trunions on the Pro Maganum rockers has to be a bonus.

 

Any weight saved over the nose is huge for a performance application. Even 2-3 grams. If the Pro Magnums or Ultra-Pro Magnums we’re lighter over the nose...total weight doesn’t matter...it would be huge for the market. Steel is the material of choice for rockers, hands down, but finding a steel rocker lighter than aluminum out over the nose isn’t easy. I look at this stuff fairly regularly and I’ve never found one. Comps Ultra-Pro Magnum looks light on the valve side, but looks doesn’t matter. Data is needed. Comp doesn’t post their weight data for the rockers, so that indicates to me the rockers are heavy. Would be awesome to find out the rockers nose weight. I’ve never contacted Comp about this. I will get in touch with them and post up what I find.

 

Do you check that buy taking a digital scale and only weighing the nose of the rocker?

 

That's how i do it. With the trunion supported.

 

What I can say is that 1.8 Pro Magnums with Lunati springs rated at 400 lbs at .600 do just fine controlling the valves with no float all the way up to 6700 RPMs on my stock long block LS2. My rev limiter is set to 6700, but I'm sure they could go much higher, not even a hint of float in SOTP or dyno measurements. And with the stock LS2 cam I'm only getting .556 with these rockers so I'm not even getting to the full 400 lb rating in real life use. These are fullsize (not beehive) dual springs with tool steel retainers and locks. Everything is more than well controlled with the springs mentioned.

BTW, I first looked at Harland Sharp Diamond Cut 1.8 rockers and they too recommended 400 lb springs. Point being, such springs would work fine for either set of rockers.

 

Yea...they need shimmed up tho. But you won't find any issues much till you get past 6700 for the most part. And probably still won't feel sotp. You will see it on a dyno.

 

In my case, there is no point in going any higher (or even as high as 6700) with a stock LS2 cam.

 

TSP steel roller rockers are slightly heavier than stock over the tip and come with CHE trunions. For non-adjustable, street setup, they are a good piece when combined with a good spring.

I like the YT 1.8:1 as it adds a little more lift and duration. For LS1 heads, they probably aren't worth it. On LS3, the added valve lift is good above .650" since the heads flow so well there and are more efficient.

And that's really why I'd recommend roller rockers. Any valve lift over .630" needs it and really anything over .600" would benefit from the reduced friction assuming you can control the weight and MOI.

Vinci High Performance has a set of springs designed for the YT rockers... they are much heavier on the seat... like 180lbs but pretty light at open... 410 or so. The way the YTs work, you actually need a ton of seat pressure to control them at high RPM, but because of the design of the ultralite aluminum body, they don't love a lot of open pressure. I believe YT rates them to 420lbs and maybe used to rate them to 450lbs until they came out with the "pro" model with a 10mm bolt and more material on the body. I think that's good for 480 or 500lbs. Well beyond what you need for a hydraulic setup and on the edge of enough for an LLSR setup.

For most setups... stock rockers with upgraded trunions are sufficient and easier to work with using off-the-shelf components. Especially if you have heavier (and larger) aftermarket valves, aggressive lobes, and flimsy pushrods.

I think my old guide to hydraulic valvetrain setup is a good resource: https://ls1tech.com/forums/generatio...alvetrain.html

 

Oh, that's where I messed up. I was going by the calculated lift on the cam card. I didn't think about figuring out the actual lift of the cam. I get it now. Thanks for setting me straight.

 

Glad I could help!