Custom Pushrod Questions

[Sweet5ltr]

Well, my stroker is back from the machine shop and everything is down to the wire other than the pushrods. Builder stated I needed 8.450" (total length). I'm running Edelbrock RPM's with Isky Ductile Iron Adjustable Rockers.

Before I sound really stupid giving Smith Brothers a call, please correct me if I'm mistaken;
3/8" diameter shaft & ball
5/16" cup
8.45" total length

Are there any special requirements for the ductile iron rockers? Springs are 333 lbs./in. rate. Any additional info required I may need to dig up from the build?

Thanks!

 

[66Satellite47]

If the builder correctly figured the needed length correctly, what you indicate will be correct. Then you need to be careful adjusting(shimming) each rocker for valve tip location. With the EDE heads also pay attention to if they need shims under the shafts. Mine did to avoid clearance issues with the rocker body.

 

[gkent]

Check your lifters with a gauge to be sure they are 3/8". Seems to me 5/16" is more common. When you order they will want to know the "effective length" which is different than overall length. Effective length is from the tip of the ball to the bottom of the cup whereas total length is to the top of the cup.

My suggestion is to opt for "pushrod oiling" you may never use it BUT if you want to change down the road you'll have that option.

Go to the Smith or Manton website - I believe the order form will be very informative.

 

[wagonman]

Check your lifters with a gauge to be sure they are 3/8". Seems to me 5/16" is more common. When you order they will want to know the "effective length" which is different than overall length. Effective length is from the tip of the ball to the bottom of the cup whereas total length is to the top of the cup.

My suggestion is to opt for "pushrod oiling" you may never use it BUT if you want to change down the road you'll have that option.

Go to the Smith or Manton website - I believe the order form will be very informative.

Lots of good info on the Smith Bros site. Read and measure, call them and they will ask more?s. Then you will feel more uneducated. Think I called 3 times. Great customer service.

 

[lewtot184]

generally speaking hydraulic tappets will have a 5/16" cup and mech a 3/8" cup. adjusters will be 5/16".

 

[mr.belvedere]

give smith brothers a call first, before "generating" your part number. i seem to recall almost ordering them incorrectly because their ball and cup sizes are referenced in radius, not diameter(?). they caught the mistake while i was on the phone with them. it was a number of years ago, but i think thats what the deal was. had them in 2 days by the way, non stocking length.

 

[threewood]

3/8" diameter may be overkill. I am running 430lbs at lift and they recommended 5/16" thick wall. Plus, the 3/8" will probably need clearanced where the pushrods go through the heads.

Mine were a touch over 9" on Stealth heads and Crane Iron rockers. Both cup and ball were 5/16", solid EDM lifters.

 

[gkent]

I run a 5/16 pushrod with a solid roller. ,080 wall thickness.

 

[66Satellite47]

Well bend a few, then decide what's needed. Hopefully the lifter doesn't pop out and you destroy the motor (done that).

 

[Sweet5ltr]

Great info, I ran a 3/8" pushrod in my RB motor with the same cylinder heads and valvetrain so that is where the confusion was; this new build is a 470 low-deck. So now the general consensus is to go with a 5/16" pushrod diameter. I ordered an adjustable pushrod today to verify what the engine builder specified to me (8.450" OAL), before I order the custom set from Smith Brothers.