How short is too short?

[jake]

Putting my engine back together and my existing fuel pump pushrod is 3.190 and had no issues with fuel. I do have another one that I am not sure where it came from that is 3.25. I would rather stick with the existing one as I know it is hardened and good, just curious how short is considered too short? TIA

 

[stubs300]

When it won't pump up the carb anymore!

 

[heyoldguy]

What you really know is your existing one is worn .060" more than the other. I know what I would do.

 

[detmatt]

I wouldn’t hesitate to use the old one. I have a brand new aftermarket one that’s just under 3.22.

 

[stubs300]

When it won't pump up the carb anymore!

I wish I kept my old one from long ago with like 108K on it, I think it was like a 1/4" shorter than a new one?? The car was running great but left me hanging at the gas station cause it wouldn't start. It gave no warning whatsoever of going out! Good Luck

 

[Toolmanmike]

A buddies pushrod from his 440. He was having fuel delivery issues.

 

[68PK21 440.6bbl]

.

 

[Zymurgy]

1/4" seems to be when you start having issues, mine was 3/8" shorter and would barely idle.

An ideal situation if you could find NOS switch it out now. I personally would switch it out now with a brand new push rod, so I wouldn't have to deal with it later. I haven't heard of anyone having a problem with any of the new rods installed either.

 

[CBODY67]

When looking in vendor websites and such last night, it confirms the 3.22" dimension that is mentioned above, for a new one.

Consider the fuel pump pushrod as "a normal wear item" and replace it when the engine is apart rather than later, for best results/enjoyment.

Be sure to daub some cam lube grease on its ends before putting it in the engine. Just like you might do with a valve lifter.

Just some thoughts,
CBODY67

 

[jake]

I will use the new one, thank you everyone.

 

[Big_John]

Putting my engine back together and my existing fuel pump pushrod is 3.190 and had no issues with fuel. I do have another one that I am not sure where it came from that is 3.25. I would rather stick with the existing one as I know it is hardened and good, just curious how short is considered too short? TIA

I know you have made your decision and I would also replace it.

While .030 wear sounds minimal, and really it is, my concern would be if the wear will accelerate at this point.

Depending on the material, and how it was hardened, just the surface of the pushrod could be hard and you might be down into where the material is starting to get soft. Might not be too... Got a Rockwell hardness tester in your garage? I don't either...

I have no idea of how the the push rods are hardened, or of what material they are made of, but it would not surprise me at all to find that they were not hardened all the way through. This illustration shows hardening depth on gears just to give an idea what I'm talking about.