SS pushrod vs. Moly pushrod

[davidlamb78]

I've not heard anything about SS pushrods. I'm wanting to run a Mamba Jr. with 26lb springs. Are the chromoly rods better/stronger/lighter than the SS pushrods? Just curious. Any information/opinions are welcomed. Thanks.

 

[Newoldstock]

Tough question:

A lot depends on the alloys involved.

Here are some simple facts:
Generally stainless steels are stronger.
But the addition of the nickel in the stainless adds toughness to the steel and that means its although they have a higher failure strength they are simply deforming more than the molly was before it failed.

Also the molly might actually deform less under stress than the stainless below the failure thresh hold.

Stainless is harder to work with and cut or weld.
Molly is a little easier to machine and weld.

But these are general comments.
Free machining stainless steels are much easier to turn than other types of stainless.
Some Molly steels have different formulations that make them much harder.

Then there are some stainless steels that are crap too.
These are the low nickel or manganese alloyed stuff ( you see these commonly rusting and cracking up on things made in China )
These are totally unsuitable for push rods.

For your engine just buy a set of good molly rods with your Cam from Isky.
He already figured out what the best and most cost effective tubing to use, and he won't sell you something he doesn't think will work.

 

[65ShelbyClone]

CrMo is generally stronger, harder, more rigid, and less expensive than stainless. I don't think any automotive pushrods are made out of stainless, if that tells you anything. They don't need corrosion resistance and they don't get very hot, so there's no reason to use it.