The Stovebolt Site Forums The Shop Area Engine Shop push rod trueness

I rolled my push rods across a flat plate and they had less than 2.5 mil gap between the rod and the plate. Is this good enough? it will only be used around town, not the Indy 500 or even the interstate.

'55 chevy 235 in a '46 3100 truck with 4 speed manual.

Bob

I have know idea what "less than 2.5 mil gap between the rod and the plate" means.
You can straighten them easily. If you want to use the truck for around town and you want to be able to make it all the way home, I suggest that you straighten them.
Carl

What he said.
If it's bent it will bend again.

2.5 mil is 0.0025". What I mean is that I can just barely slip a 2 mil feeler gauge under the rod in various spots. Not much of a bend angle. I was only wondering just how critical all this was. If "fixing the bend" is acceptable, then I think that I will live with what I have. Don't know how any one is going to "unbend" a rod any straighter than what I have. Thanks.

Interestingly enough, I have found the original gm push rods bend pretty easily. The aftermarket trw and sealed power replacements are actually stronger and frankly not all that much money.

How are you placing the push rods on the plate? 235 push rods have bulbous ends. Laying them on a plate with bulbous ends touching, you would have a huge gap between the plate and the middle of the rod, not .0025 inches.

That was my thought as well Carl. Bob, can you post a picture of how you're measuring them?

I hope this does it. Just by chance, my Dad's old table saw happened to have two grooves at just the right distance to clear the 2 ends of the "dog bone" and also clear the ends of the rod. I verified the flatness of the machined, cast table top. I am confident of my measurements. So, I guess that we are back to my original concern.

Thanks,
Bob

A picture is worth a thousand words. IMHO you're good to go if the engine has stock valve springs. I imagine you'd find brand new pushrods that would measure similar. I imagine there are some who disagree but I'd use them if it was my decision. I've used worse over the years without issue.

Thanks for the response. Sort of what I thought, but wanted to have some input. After all, they aren't machined parts.
Bob

2.5 means nothing, is that .025" or .025mm? Or something else? In The U S, we measure in inches.

Ed

He said 2.5 mils. A mil = 0.001 inch, so 2.5 mils would be 0.0025 inches. The mil is typically used for paint film thickness measurements.