Hey fellas need some help, Ok I have a ls6 pkg on my motor ok, I wanted to know
if I put 1.8 roller rockers on there how much will I gain and will they make to car sound choppy?

 

1.8 rockers are to be used for cams with a high lift, otherwise sticking with stock ratio will suit you just fine. Too much ratio will open the valves too quickly and can cause valve float at high rpm. It also multiplies the spring pressure seen on the cam lobes, so running too much ratio can wipe out a cam in no time.

Also 1.8's can not be used with big cams, without other modifications.

 

First, how are they pointless if they are not used for a high lift cam? No matter what the cam's lift is they add to it thus letting in more air to make more power. Second, explain to me how a 1.8 rocker will make a valve open quicker? The lobe of the cam makes that decision not the rocker and valve float is by weak valve springs not going to a 1.8 rocker. Third, I can't see a 1.8 adding more spring pressure. When you buy springs there is seat pressure and open pressure. The open pressure is just that there is not a different open pressure for using different ratio rockers. If it did multiply spring pressure, the lifter would collapse before it wiped out a lobe due to it being that all ls1's are roller lifter motors.

I would like to also know why a 1.8 rocker cannot be used on a big cam? Ramp rate plays the role here not just the size of the cam. You can have a small cam with a fast ramp rate.

 

Adding a higher ratio rocker multiplies cam lift and the load on the pushrods, lifters, and rocker arms. Adding to much ratio will open the valves to quickly and can cause valve float at higher rpms. This is why using a bigger cam that operates at higher rpms will cause float with higher ratio.

Agreed - Yes a higher ratio rocker adds lift, but also changes the cams duration. Because of this, the valves speed up opening/closing quicker than with a lower ratio rocker. Makes the cam act "bigger" than what it really is.

This is why higher ratio rockers are better on a smaller cam, you can get great results from a small cam with higher ratio rockers without putting a monster cam in. But when using a bigger cam, you have to take into account that the pushrods may not have enough clearance to clear the hole in the cylinder heads. Adding a bigger cam with higher ratio rockers can also affect PTV clearance. Adding the lift could cause the valves to tap the pistons. You may also out lift the spring height. Also, while adding ratio, you also add timing.

Sure you can use higher ratio on a bigger cam, but from what the OP was posting about, sounds like he just wants to make some more HP while maintaining street-ability. His money could be better spent elsewhere, than buying new rockers. If anything, send of stock ones off and have them worked on.

TO THE OP,
You would gain very little in regards to the money spent, maybe 5-10HP at peak. You will need dual springs if u dont already. Many popular cams do not even recommend higher ratio rockers. Want more HP or more lift spend the money on a cam instead.

 

I got ya I'll look into that some more thanks guys.

 

dude you will be fine with running 1.85 rockers on the ls6 cam. Hell slp made a rocker/ spring package for the ls1/ls6 cams... I have the slp 1.85 rocker/ 600 lift spring package on my car now, works great.

 

This where I disagree... the rockers are going to add power across the whole curve, not just peak!

 

Hey bro will it make my car have a choppy sound?

 

you will barely notice a difference in how it idles... expect to see about 9whp/ 15wtq gain across the curve w/ 1.85's. You may even see more than that since you have 243 heads... The gains I posted were on a 241 head, ls1 cam, ls6 intake motor. If you search around you can pick these up used for 360.00 range.

 

my advise is to make sure that your set up is set up to run with the new rocker ratio if not you will encounter issues, the LS6/LS1 heads and cam are set to run with a 1.7 rocker ratio and are build as such, the C6 LS6 is made to run with a 1.8 rocker ratio and is build from the cam up to run with such ratio. I have seen more than one person do this and more than one person end up with valve train failure because they don't take the time to make sure that your set up is done correctly. Also remember that the Ls6 cam is ground to run with a 1.7 rocker ratio.

 

Slp specifically designed the 1.85 rockers for the 5.3, ls1, ls6 camshaft. Whats the danger??

https://ls1tech.com/forums/dynamomet...5-rockers.html

at the time these rockers were too expensive for the gains... Now they can be had for alot less money and provide decent gains in the whole power curve. I would expect a 243 head car to pick up more on the hp side aswell. But 17wtq gain is pretty impressive imo...

 

I don't think that I said anything out of line please refer back to previous post.

Now different strokes for different folks. Many of the mechanics that I learned from advise against this type of method of raising your final lift numbers and if you are going with this to use a cam ground for the 1.85 rocker ratio, or get the cam with the final lift numbers you want but again different people different opinions different ways of doing work. Not saying any one person is right or wrong just different ways of attaining what you want.

 

You will be just fine running the 1.85 rockers. I would recommend a better valve spring to control everything at higher RPMs though as well. And lastly, I'd like to recommend Yella Terra rockers. I've had good experience with them (Never ran a hgher ratio though).

Here's a link, but in summary, Patrick G picked up 13 rwhp, 7 rwtq and picked up power throughout the entire curve.

https://ls1tech.com/forums/dynamomet...o-results.html

 

Man I thank all of you for being so helpful to me.

 

Here is a chart for what spring to use with the rockers.

http://www.slponline.com/view_product.asp?P=50185

 

ill only pick this out of your post of ignorance....

first off...the valve will open quicker, because it has to travel a further distance in the same amount of time. yes the cam decides how fast the valve opens, but when you increase the rocker ratio, its going to open further in the same time the cam wants it open, therefor having to move faster.

think about it this way....

you have 5 minutes to go 5 miles...you have to travel 60 mph the entire way to get there in 5 minutes...

then i tell you you have 10 minutes to go the same distance...you have to travel 30 mph to get there in 10 minutes...

see?

or here is an easier comparison directly related to lift and rocker ratio

you have 5 minutes to travel 5 miles....60 mph the entire way...

now you have 5 minutes to go 10 miles...120 mph the entire way....

you have to move faster to cover the same distance,.

second, when you open the valve further, you compress the spring more. if the spring is not rated to how far your compressing it, it wont be able to close the valve when it needs to...hence valve float...

 

thats on LS3 heads...thoes heads really like lift as stated. on a stock 346 with cathedral port heads, you will be lucky to see 5rwhp. hardly worth the money spent.

 

I interpreted in the second post of this thread that he was saying that the valve event would take place earlier. I see in his fourth post he cleared that up.

 

 

Not a problem.