How did this happen to my pushrods?

-
blackhand

blackhand

Well-Known Member
Joined
Oct 7, 2010
Messages
174
Reaction score
5
Location
Seattle
I've been chasing a high RPM misfire for a while now and I'm pretty sure that it's being caused by tired old valve springs. Anyhow, I pulled apart the rocker assemblies and pushrods for inspection. The rockers and shafts look great but the pushrods were coated in sludge, I'm assuming from sitting for a while before the previous owner did a basic rebuild on the engine. I noticed a kind of spiral pattern on about half of the pushrods but I thought it was just how the sludge built up over time given that the pushrods are always spinning and moving up and down. I decided to clean the sludge off and found that the pushrods are actually scored in this spiral pattern.

I'm wondering what could have caused this and is it anything I need to be concerned about? When the rockers and pushrods are assembled and in place the pushrods don't appear to be rubbing on anything, not even close really. Even if they were rubbing somewhere, how would they end up with a uniform pattern going all the way up and down the length of the pushrod?? Anyone seen this before?

Also, the ball ends look great, they have a mirror finish and no burrs or scoring of any kind. The pushrod looks a little bent in the picture, it's just the shadows. All 16 are actually dead straight and roll across my stainless steel workbench perfectly.

Thanks everyone
 

Attachments

  • pushrod 1.jpg
    66.4 KB · Views: 701
  • pushrod 2.jpg
    78 KB · Views: 605
That looks like a semi slow twisting of the steel itself.
Big cam and springs in it?

Look at the heat buildup at the ends that caused them to be discolored.

From the looks of it you should use hardened pushrods.
 
It's from the rolling process used to make cylindrical steel. No big deal. The dies were about due for replacing that day.
 
Interesting... really hadn't considered that!

It has a very mild street cam (about .450 lift) and I'm fairly sure the springs are stock. It's a '78 400, the springs were probably pretty weak from the factory and they are definitely weak now. I can actually spin a few of them with my bare hand now that the rockers are off of there.

Anyhow, I think these pushrods are probably going to end up in the trash can.

Thanks for the quick reply
 
jos51700 said:
It's from the rolling process used to make cylindrical steel. No big deal. The dies were about due for replacing that day.
Click to expand...

Great, mystery solved! I searched all over google trying to find something similar to this and came up with nothing. FABO rocks
 
blackhand said:
Great, mystery solved! I searched all over google trying to find something similar to this and came up with nothing. FABO rocks
Click to expand...

I have seen pushrods with a twisted looking surface to the steel, but the discoloration from friction heat is what I was questioning.

It would be interesting to mesure them and see if metal actually moved.
I'd wager that thier lengths vary somewhat.
 
TrailBeast said:
I have seen pushrods with a twisted looking surface to the steel, but the discoloration from friction heat is what I was questioning.

It would be interesting to mesure them and see if metal actually moved.
I'd wager that thier lengths vary somewhat.
Click to expand...

Ahh yes, I noticed that too. Comp has a set of heat treated, one piece pushrods in the length I need. I think I'll order a set of those with my new springs soon. Thanks for the advice
 
i have seen a set like that before, so i think there is nothing wrong with them.

maybe throw up a for free ad, someone might want them. i would want them but cannot afford even the shipping! you are a long ways away
 
Man in my thirty years of wrenching i have never seen a push rod look that way!!Thats known as candy caning ,,I' am sure the did not look like that when they were installed.By the way a .450" lift is no small cam!!Check comp cams recommendations for valve springs with that kind of lift!!!Ya know they rotate,for steel to twist like that something is binding them,,the rods in question, were the all intake or exhaust??Looks to me like your springs are bottoming out,if that's the case i'll bet that thing would not fall out of a tree if you pushed it!!!Get rid of that cam too when you fix this for the lobes are destroyed!!!! If you have friction or binding you are losing horse power and races..!!! Oh ps!!shirt can those lifters too,,Oh by the way .450" is not huge for a mopar "b" motor but big enough to replace the valve springs i think!!!Good luk and MOPAR TO YA!!!!
 
jaybyrd64 said:
Man in my thirty years of wrenching i have never seen a push rod look that way!!Thats known as candy caning ,,I' am sure the did not look like that when they were installed.By the way a .450" lift is no small cam!!Check comp cams recommendations for valve springs with that kind of lift!!!Ya know they rotate,for steel to twist like that something is binding them,,the rods in question, were the all intake or exhaust??Good luck....Jay
Click to expand...

Jay, i looked at this thread a while back and didn't post but i have to agree with you. I've got 35+ yrs. in this myself with every American brand and have never seen this either. I've bent um', broke um' but never twisted um'.

P.S. Welcome to the site.
 
Sorry , there is no way that a .450 lift cam uses enough spring pressure to do that to a pushrod , it would have had to have been almost welded to the lifter and the rocker for that to happen.

A stock 383 2bbl engine has a .450 lift cam ...
 
Just wanted to post a follow up here... I am very doubtful that the pushrods have twisted. I tried to post as good a close up photo as I could but it still doesn't show quite enough detail I think. The pushrods are actually scored with the spiral pattern, as best I can tell those are actually scratches in the surface of the pushrod. I couldn't think of any way for them to get scratched up in that pattern, but one poster in this thread mentioned that it was probably the tooling used to roll the pushrod when it was assembled. I think that's probably the most likely cause. I'm also glad that others have seen pushrods just like this, I'm thinking now that I probably don't need to worry about them.

My cam has a moderate amount of lift but I don't think that it's enough to cause coil binding on the springs. Also, the springs are very tired and old, so weak in fact that I can spin some of the springs by hand. Very doubtful that there's enough spring pressure there to put undue stress on the pushrods. FYI, new springs are on the way and I can't wait to get them in and see if they eliminate my high rpm misfire.

Thanks for all the replies
 
oldkimmer said:
..............I've seen at least 10 mopars with pushrod just like that..........kim...........
Click to expand...
so have i

JohnRR said:
Sorry , there is no way that a .450 lift cam uses enough spring pressure to do that to a pushrod , it would have had to have been almost welded to the lifter and the rocker for that to happen.

A stock 383 2bbl engine has a .450 lift cam ...
Click to expand...

100% agreed

i have ran a .509 in a BB with a completely stock valve train and pushrods with no problems ever
 
You must log in or register to reply here.
-

Back
Top