1.8 ratio rockers?
Thread Starter
Racer
Joined: Sep 2007
Posts: 498
Likes: 1
From: Fontana CA
1.8 ratio rockers?
Want everyones opinion as next week I'm having CMS Motorsports install, AR headers with high flow cats, Fast 92, LS2 TB, Cam, LS2 timing Chain, LS6 oil pump, NGK TR55 plugs,Patriot valve spring (Golds), LS7 clutch, LS2 Flywheel, Remote bleeder,RAM adjustable master cylindar,C6 Zo6 shifter, slave cylindar. Want to know what you guys think off adding 1.8 roller rockers to this setup. Will it add any power? Any problems? This would be on the stock heads on my 99' Vert.
Burning Brakes
Joined: Jul 2007
Posts: 881
Likes: 2
From: hill billy hell
they will change the lift of your cam, need to make sure you have
proper piston to valve clearance. Yes they will add power because you
are adding to the cam specs.
VALVE LIFT ÷ ROCKER RATIO = LOBE LIFT [ CAM LIFT ]
LOBE LIFT X ROCKER RATIO = GROSS VALVE LIFT
proper piston to valve clearance. Yes they will add power because you
are adding to the cam specs.
VALVE LIFT ÷ ROCKER RATIO = LOBE LIFT [ CAM LIFT ]
LOBE LIFT X ROCKER RATIO = GROSS VALVE LIFT
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
The size cam you are running (224ish) with stick heads will not cause a clearance issue, but the piston to valve clearance should be checked anytime the cam or heads are changed. The 1.8's will increase valve lift, increase the overlap triangle but will not change timing events on the valves. You don't need a girdle. There are two ways to go, one is the Crane, which are stud mounts, and the other is the Yella Terra's, which are pedestal mount. Ramp rate on your cam selection may have more to do with the selection of a larger rocker ratio.
However, having said all that, since this is part of a cam swap I would just go with a good cam selection for what you are seeking in performance and 1.7 roller rockers. The roller rockers won't buy much power (maybe 5 hp) but they will buy you vastly improved valve train geometry and lower valve guide wear.
However, having said all that, since this is part of a cam swap I would just go with a good cam selection for what you are seeking in performance and 1.7 roller rockers. The roller rockers won't buy much power (maybe 5 hp) but they will buy you vastly improved valve train geometry and lower valve guide wear.
Burning Brakes
Joined: Jul 2007
Posts: 881
Likes: 2
From: hill billy hell
Yes,because of the roller tip, They call the stock rockers roller because it has a roller fulcrum. IMO they are not true rollers unless you have the
roller tip.
I do not think you would benefit from a girdle seeing how the stock rockers
all mount to what is called a Pedestal rail. some brand of roller rockers
come 2 on a pedestal they can even get more complex rails.
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Safety Car
Joined: May 2003
Posts: 3,814
Likes: 105
From: Dearborn Heights Michigan
Have the same comp cam timing with 1:8 Jesels. Had to clear (hand grind) a bit of clearance in the valve covers, but, no biggie. the 1:8's will definitely give more performance , but, I don't know how much.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
I agree with Vettenuts. It increases valve speed and valve lift, but you better make sure your geometry is proper. If not, you'll smoke your valve guides due to the side loads. Proper rocker geometry isn't always achievable regardless of how you adjust the rockers. I am not a rocket scientist when it comes to this, but have however spoken with a highly respected engine builder (Erik Koenig at HKE) and he explained this to me. The heads I purchased came with the Crane 1.8's and we are going to go over them when I get to his shop to pick up my new motor. If you use 1.8's get your geometry as proper as you can then order the proper length pushrods to match.
What 1.8's you had ?
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
