ok, i need help, i just got the HS 1.6:1 non-adj rocker arms and need to find the right length push rod for my 96 5.2 magnum, i would really like to find a nice long write up on this, but any help would be great.
thanks
dave

 

Dave,
I installed the same rocker arms in my 360 and used the factory pushrods. Since the 1.6 HS's are the same ratio as the 1.6 stock pushrods, stock is what you can use. If you're looking to increase the lift even more, somebody else will have to chime in here.

 

Unless you did head work, swapped heads, or swapped the cam, stock should work fine. When I did my build up, I ordered 3 sets and returned the ones I didn't use.

 

I actually did have a performance cam installedwhen I did mine, but the lift allowed the use of stock size pushrods. I replaced them when I installed the HS rockers just for a feel good feeling. I purchased them through NAPA and they matched up exactly with what the engine builder used when he installed the cam.

 

i do have a comp cams camshaft with, .480 of lift, i have been told by the guys at HS and summit to check and make sure that the push rod length is right i already bought the adj, push rod, and way wondering if i need a soild lifter... and any other items i dont know about.

if i didnt have to do this that would be great i just had both companies tell me that this is the best idea, but i geuss i could order three of four diff, sets and return the ones that dont fit.

thanks
dave

 

It's really best to have adj. rocker arms if you are running a performance cam. It is important to getthe preload right.You can make a mock-up lifter by removing the retaining clip off one of your old lifters, then disassembling the lifter. Cut a piece of dowel and insert it into the lifter, then reassemble it. I have heard of people stacking washers in there, but I think that would be less precise. I used a shaper to remove material from the dowel until it measured correctly using a micrometer. To check the geometry you can color the top of the valve stem with a sharpie. Assemble everything with the mock lifter, and hand turn the crank. So that the valve opens and closes several times. The rocker will wipe the sharpie away where it makes contact. I did not use this method. I read about it after I was done, but will be using it from now on. I used a small flashlight behind the rocker/valve stem and watched it through the rotation.

 

sorry , but wtf? take apart my lifter and, put in a a dowel level withthe top of the lifter? then put the adj. push rod in there with sharpie on top to see if it rubs off.

i would have used the adj rocker arms but the guys a hs said this wouldnt be the best idea for a DD motor, they say those will come lose after so much use.

 

My cam doesn't quite have the lift of yours as it was ground for increased torque for towing:

<I>Camshaft Specs:</I>
210/215 @50 110 lobe sep
Lift: 462 - 470
Duration: 288 - 284

These specs, along with the HS 1.6 rr's, allowed me to use stock pushrods. Mopar performance, along with most other pushrod manufactureres sells an adjustable pushrod that can be used to determine the correct optimal pushrod length when building up an engine. I think mopower was just trying to give you another method of doing the same thing without resorting to purchasing a tool. Drivetrain geometry can be really tricky to determine, but it is so critical in the performance of the engine. I agree with not having adjustable RR's for a daily driver unless you really enjoy adjusting them.As far as the right length pushrods, too long and they open the valve too much causing the valve to hit the piston, cusing coil bind, and beaking valves. Too short and not enough fuel gets in resulting in a lean burning engine and burnt valves. Either way, you've another engine build on your hands.The pushrod should move the rocker arm where it only contacts the valve stem in the center of the valve stem diameter.

 

Whether you install new lifters or reuse the old ones the lifters will be devoid of oil (bled down) when you put your stuff back together (unless you do it really fast). It is a common practice, when building or moddinga hydraulic roller cam motor, to use a mock-up lifter to check valvetrain geometry.

 

by mock up lifter do you mean a solid lifter, and then measure the push rod lenght, i already have the adj, push rod, all i need to know is

what kind of lifters to use, my hydr. lifters or do i need a solid one
and should there be any play in the rockers arms and if so how much, this could be the valve lash thing i have heard about, or if they should be tight to the valve but not opening it.

thanks
dave