8.Lug

It's my understanding that the higher ratio is best for keeping the arc of the wipe pattern as straight as possible - so why not always use 1.8:1 rockers on everything? Flex in the rocker itself? Well let's assume I'm using the highest of quality shaft mount rockers - are there still cons?

.boB

iTrader: (1)

You're effectively increasing the lift and duration of the cam. That increases the potential for piston to valve contact if you already have an aftermarket cam. And you'll increase side loading of the valve stem.

If you have a stock cam, there really isn't a down side if done correctly.

Che70velle

iTrader: (6)

Springs. The higher the ratio, the faster the valve opens, regardless of ramp rate. A faster valve opening is great for performance, IF your PTV is setup correctly, but it’s much harder on valve springs.

vettenuts

iTrader: (4)

Really depends on your setup. If you are stock, then the new springs and likely pushrods required to make them work are questionable costwise vs. just swapping the cam. If you are running something like the GM hotcam that has a lower lift, then some have seen pretty good results with the additional lift.

Need more information on their intended use. After all, GM uses them stock in some of the later motors.

AnotherWs6

iTrader: (17)

Great question. I have a rebuilt LS1 with new replacement type pistons, 243's from an LS6 with factory yellow valve springs and valves milled 15 IIRC, and the 385hp version of the LS6 cam. This was done because the parts were available and cheap. Obviously I'd rather have a "good" cam, but I don't want to get new springs etc. It's just too much money. Would a set of 1.8's be a worthwhile solution to getting a little bit more out of the motor?

8.Lug

Let’s say for a higher revving solid lifter NA motor.

HioSSilver

iTrader: (8)

I've had 1.8s on my ls6 for a long time now with no issues.

For any custom cammed motor like your speaking of i would think they are preferred as long as the grinder knows you have them.

WOThrottle

Probably the biggest disadvantages to using a higher ratio rocker is the added force applied to the pushrod side of the valvetrain, and the higher valve lift rate. That means the pushrod, lifter, and camshaft see more force applied to them. Changing the rocker ratio does not affect the camshaft duration, only the rate of valve lift and total valve lift. With that being said, for most things that people do here none of that is a big issue if you're only going from a stock rocker to something with a 1.8 ratio.

big hammer

Higher ratio rockers have a small duration increase when measured at .050. Nothing wrong with them in a stock cam. You'll need better springs though

big hammer

I think lt1 rockers are 1.8 from factory

KCS

iTrader: (20)

It definitely does, but as hammer said, it's usually not by much.

WOThrottle

I guess that my comment was misleading. I meant to say that it doesn't change seat duration.

AnotherWs6

iTrader: (17)

Really? Seems like a fairly small change. We're talking about a roughly 6 percent increase in lift. I'd think that factory springs could handle that, they have to have some "extra" built into them.

KCS

iTrader: (20)

It wouldn't be a bad idea. Think of the rocker as an amplifier for the lobe. It intensifies everything, including acceleration. Compared to a stock 1.7 rocker, an aftermarket 1.8 rocker will usually carry some extra weight over the valve too. The combination of those factors could easily cause some issues.

MuhThugga

On a factory cam, the LS6/2/3 springs can handle the added lift.

You should do the math whenever changing rocker ratio to see if your springs will be happy:
(Lift/Old Ratio)(New Ratio)=New Lift

Also, if you plan on changing cams after switching to a 1.8, you have to take that into consideration when selecting a camshaft or else you will wind up with a very unstable valvetrain.

Darth_V8r

iTrader: (4)

Personally if I was doing a rockers only upgrade, I'd use psi1511, titanium retainers for weight savings and valve control. And 5/16 x 080 pushrods. Valvetrain stability is always a good idea

gagliano7

There are some good cams that will work with your stock springs which would be a better upgrade than rockers.

https://www.briantooleyracing.com/tr...e-iii-cam.html

https://www.briantooleyracing.com/tr...ge-iv-cam.html

Just some examples.

AnotherWs6

iTrader: (17)

Yeah, that's how **** snowballs. And then my sealed up motor has to come apart.....

Thoughts about the stage 3 vs factory LS6 cam?

AnotherWs6

iTrader: (17)

Ebay makes me mental, so many tempting things on there.....

8.Lug

Don’t get me wrong, I LOVE ebay, every single thing on my car came from there including my L33, but $200 for aluminum rockers? This is exactly the type of thing that causes people shun eBay. Stick to name-brand stuff when it’s as important as this.