Pushrod Question

[Red_Duster]

Hey everyone,

As stated in my other threads, first real big adventure into valve train. Now that I have my heads on (more or less) I measured pushrod length and ordered a set (3/8th cup/ball like what I had. They showed up today and I noticed that the bottom tips are different. I dropped them in and length looks good, but before I rotate it for piston to valve clearance and to check pushrod clearance, are these going to work or do I need to send them back and get a 5/16 bottom ball?

Edit: Lunati hydraulic cam in a 383.

 

[GTX JOHN]

I think you need to send them back.
They will not fit securely in the lifter if
it has the smaller diameter circle.
Try testing one in your new lifters and see.

 

[sabre67]

subscribed

 

[RustyRatRod]

What's important is the radius of the tip. If the radius is the same, the small pushrod will fit and work. Otherwise, send the small ones back.

 

[Red_Duster]

Thanks for the feedback everyone. I should have mentioned the BIGGER pushrod is the new one from Comp Cams. Dropping them in a lifter, the radius seems to match, and even with no downward pressure, just pushing laterally, it doesn’t want to jump out of the lifter.

 

[PRH]

What’s the part number for the new pushrods?

 

[Rat Bastid]

Take a picture of the pushrod seat in the lifter. That what dictates what ball goes on the end of the pushrod.

 

[AJ/FormS]

put a few drops of oil into the pushrod cup of the lifter. then drop the small ended rod into the cup and pop it back out. Sometimes they make a neat popping sound as the pushrod and lifter separate, and the p-rod will tend to stick to the lifter like a weak magnate, during separation.This would indicate a match. Then try it with the larger p-rods, watching for the same indicators.

 

[pishta]

the B used smaller ball pushrods in the early years. you can change lifters or return the pushrods.
...'68 and later are 5/16" both ends, the '67 and earlier are 5/16" top and 1/4" bottom...

pre 68 'small ball' lifters
Comp - 824-16
Eaton/SBI - VL8
Johnson - A-812
Federal Mogul - HT1812

 

[Rat Bastid]

Here is a picture of two Chrysler lifters. One is a mid 1990’s lifter and the other is whatever Jim at Racer Brown sells. You can clearly see two different sized seats and they do not take the same ball size.

This is picture of my pushrods for the lifter on the right.

You can see that one end has the small ball for the rocker and the other end has the bigger ball for the lifter. That’s why you have to measure the radius of the cup in the lifter, or at least be able to see the difference because that cup is what determines what ball size you need on the pushrod.

 

[PRH]

Ages ago when I was first getting started in the car hobby, and didn’t really know anything about anything(but thought I did), and didnt really notice the difference between pushrods that had 3/8” or 5/16” ball ends for the lifter end....... I used whatever showed up.
I never had an issue.

 

[Jim Lusk]

If the pushrod fits in the lifter you are good to go. You probably have the equivalence of the later lifter.