Merlin

Just wondering if anyone knows whether or not I will run into piston to valve clearance issues with the ASA cam (226°/231°@.050, .525/.525 lift, 110lsa, 5° overlap I believe) by adding the 1.85:1 rocker arms? According to the manufacturer of the rocker arms, they add about 10% lift or should put the lift around .570 for the ASA cam. I think this would be a really neat setup to try out so any help is appreciated. Thanks

cscollis

I have been running 216/220 on a .525 lift for a year with no problems with Crane 1.8 Rollers. I just installed a bigger cam and have the rockers for sale. $300 plus shipping if you want to try them.

HALLZ

iTrader: (1)

Your lift will aprox 571.32xxxx and your dur will go up aprox 3* on the intake and the exhaust. I would recommend ordering a adjustable push rods and check for the proper length. ( http://www.compcams.com/information/Products/Pushrods/ ) My roommate is running the ASA cam and non adjustable rockers with 7.35 pr's and they are still a tad bit to long. The idle and low speed drivability along with over all performance suffers. I am running adjustable 1.8 on the std. hotcam with no PV problems. (yes I know its a different cam)

You might take a look at cams with a < .570 lift and 230/236 on a 110 and see what the PV is. From the research I have done the GM off-road cams were designed with 1.8's in mind to meet restrictions on the class they were designed to run in.


and just some FYI here is some info from a cam manufacture regarding rocker ratio.

"How does an increase in rocker arm ratio improve the engine’s performance?

The lobe lift of the cam is increased by the ratio of the rocker arm to produce the final amount of valve lift. A cam with a .320” lobe lift using a 1.50:1 ratio rocker arm will have a .480” valve lift (.320” x 1.50 = .480”). If you install rocker arms with an increased ratio of 1.60:1, with the same cam, the lift would increase to .512” (.320” x 1.60 = .512”). The engine reacts to the movement of the valve. It doesn’t know how the increased lift was generated. It responds the same way it would as if a slightly larger lift cam had been installed. In fact, since the speed of the valve is increased with the higher rocker arm ratio, the engine thinks it has also gained 2° to 4° of camshaft duration"
www.cranecams.com/camvtfaq.htm



Good luck