Roller Rocker.

[andrewespo]

I looking to get 1.6 roller rocker arms. How do I know what size stud to get there is two choices 3/8 in. and 7/16 in.

[SVTcobra306]

That's for stud mount if you are choosing to machine your heads for studs and guideplates. Look for the pedestal mount-bolt down rockers for a bolt on deal. 5/16 bolts.

[Future303]

Can one benefit from Roller Rockers are lower RPM's? I don't usually take my engine over 4000rpm's, would I see a benefit in the upgrade?

[eillob]

Originally Posted by Future303

Can one benefit from Roller Rockers are lower RPM's? I don't usually take my engine over 4000rpm's, would I see a benefit in the upgrade?

If your talking about replacing your stock rockers for aluminum aftermarket rockers, yes you will benefit from it. The difference won't be huge but you will free up some hp.

[StangNut86]

a worthwhile investment when you're ready to start making serious mods. if you're gonna get aftermarket heads, i'd hold off till then and get stud mount rockers.

some might say you have to use a stud girdle with these, but you only really need them if you're gonna spin the motor significantly higher than stock.

[andrewespo]

What's the difference between 1.6 rockers and 1.7's?

[eillob]

Originally Posted by andrewespo

What's the difference between 1.6 rockers and 1.7's?

1.7 roller rockers give your camshaft more lift. And more lift means more air in the cc which equals more power.

[duplox]

Originally Posted by eillob

1.7 roller rockers give your camshaft more lift. And more lift means more air in the cc which equals more power.

also means more stress on your valvetrain, less life for your cam. It'd be better just to get a new cam, but if you don't want to do the work...

[andrewespo]

Originally Posted by duplox

also means more stress on your valvetrain, less life for your cam. It'd be better just to get a new cam, but if you don't want to do the work...

I thought roller rockers were beneficial to your motor and make things smoother.

[SVTcobra306]

Swapping from 1.6 to 1.7 RR isn't that big of a stress increase, esp. with a stock cam. IF you're staying stock cam, I say go for the 1.7's. Valves open farther and slightly faster, with less friction due to the roller. Not many drawbacks there...

Just a little noisy, sounds kinda like a sewing machine under the valvecovers, but quieter.

[duplox]

Roller rockers themselves are better, but increased ratio rockers can cause some trouble. they WILL wear your cam faster, since they're moving the valve a longer distance in the same ammount of time. But its not that big of a difference, and if you're on a stock cam, its probably fine.
A 1.6 to 1.7 ratio change will bring a .450" valve lift cam(on 1.6 rockers) to .478125" valve lift(on 1.7s). Duration stays the same - This may be the main problem. You may accellerate your valves too quickly and either overload your springs or float the valves earlier. But it'll probably be fine.

[eillob]

Originally Posted by duplox

also means more stress on your valvetrain, less life for your cam. It'd be better just to get a new cam, but if you don't want to do the work...

Don't agree with you and heres why. Whats the difference between a stock cam with 1.7 RR and a high lift cam with 1.6RR? Lift is lift whether it comes in the form of a higher roller rocker or a high lift cam. How do you figure one is gonna put more strain on the valve train vs the other? And as far as cam life goes, unless your running a large cam that ususally isn't an issue either.

As far as the comment on valve noise. Im running them I don't have noise and I know others who run them and have no noise. So if your getting some there probably not adjusted properly.

[duplox]

It clearly puts more stress on the valve train. All the stress in the valvetrain mainly comes from one thing, the valvespring. now, if you increase your rocker ratio, you both increase how far you have to compress the spring(more compression means more weight/force required to get the spring there), and you're doing it in the same ammount of time.
You can have problems with wear, valvetrain geometry, valvespring issues(binding/resonance/increased wear), and you won't get as much power out of it as changing the cam.
Say your stock cam has a lift duration at .050 of 212*, and a lobe lift of .279". This means with a 1.6 rocker, you have a lift of .447". Say you swap to a 1.7 rocker. Now you have a lift of .475". Duration stays the same, since the ratio of the rocker has nothing to do with it.
Obviously this changes the lift-duration relationship, and they were like that for a reason. You certainly won't make as much power as a cam designed for .475" lift and more duration. But again, a 1.6 to 1.7 rocker change, especially on a stock cam, isn't much. You probably will be fine. Your biggest problem will be valvetrain geometry.. I could go into that now, but its thanksgiving! Maybe tomorrow.

[andrewespo]

Now I'm confused between 1.6RR and 1.7RR. Which to get, I heard 1.7 will raise lift and create more stress so is 1.6 a more conservative choice and a better idea? I mean what am I gaining from putting them in, sounds like little to nothing from what everyones saying.

[eillob]

Well I think duplox and I are making two different points. My point here is NOT that a higher lift rocker is better than just putting in a cam. Let me just throw that out there because there is obviously some confusion. Trust me if I was about to put a motor in my car and had the opportunity to put a custom cam with lift and duration specific to my set up that is definately the way to go. However if we are talking about a situation similar to mine where we have a 100,000 mile plus motor and plans to replace it in a year or so than I think a stock cam with some added 1.7 roller rockers is a good answer to some additional hp without the hassle of ripping apart a motor that will be replaced soon anyway.

Now since we are talking about Roller rockers lets just throw duration out the window for now because like duplox mentioned earlier RR don't play into that. What Im talking about is lift. Lets use say a stock cam and an E cam. The stock cam has a lift of .444 and an E cam has a lift of .498
Now my point here is this

Stock cam w 1.6 RR equals .444 lift.
w 1.7 RR equals .477 lift.

E cam w 1.6 RR equals .498 lift
w 1.7 RR equals .529 lift

Now im not saying that a larger roller rocker will not put more stain on the valve geometry, but explain to me how a stock cam w 1.7 RR is putting more strain on valve geometry over an E cam w 1.6RR
In this situation the E cam clearly brings more lift to the table than the stock one does. But combined with your spring friendly 1.6 RR your still putting more strain on the spring because your making more total lift than the 1.7 RR and the stock cam.