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Never seen this before have you? Pushrod question.

Whiplash

Well-known member
Joined
Nov 21, 2003
Messages
276
Location
New Jersey
Corvette
71 Kandy Burple Conv / 02 MY Z06
With all my crate motor woes I've gone round and round getting things fixed. I have some semi-professional help coming to the house potentially this weekend. He's got an 8 second Nova and is supposed to be a real wizard so I've got my fingers crossed.

The reason for the post is to ask about something I noticed when I was setting my valve lash that I've never seen before.

On a few, not all, pushrods I noticed that about 3/4 of an inch down from the top there is a small hole. I thought this was strange and that the only holes in pushrods were at the ends for the oil to run up into the valve train through. I thought perhaps the holes I noticed were meant to spray a little oil around the springs. I can't remember which valves specifically they were on but I recall that they were on a few of the valves toward the front of the motor. The holes don't appear to be due to any kind of wear. They are clean round holes.

Has anyone ever heard of this or seen this on a pushrod? Could this be why I'm getting noise even though I've set the lash twice? The mechanical wizard I spoke to today had never heard of this but couldn't say for sure that they weren't supposed to be that way. This is the first motor I've opened up in over 20 years so I wouldn't be surprised if you told me this was normal.

I didn't think to take a picture at the time because my hands were covered in oil and I was more focused on getting the lash right. I'm going to pull the covers and review the lash again this weekend. I'll post pics of what's in there then.
 

wishuwerehere82

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Joined
Sep 6, 2003
Messages
2,314
Location
Rochester, NY
Corvette
Red '82 Coupe,Sebring Silver '98 Coupe
That's a new one on me.
If there are only holes in some of them, is it possible that the other ones are upside down? Still, holes would let the oil drain down out of the rods and cause temporary loss of lubrication after starting and the lifters pump up. Wierd!
 

Whiplash

Well-known member
Joined
Nov 21, 2003
Messages
276
Location
New Jersey
Corvette
71 Kandy Burple Conv / 02 MY Z06
That's a new one on me.
If there are only holes in some of them, is it possible that the other ones are upside down? Still, holes would let the oil drain down out of the rods and cause temporary loss of lubrication after starting and the lifters pump up. Wierd!

I thought there might be some that were upside down too so I pulled a few of them and they don't have any holes.

:confused

This could be the cause of my rocker knock. I was thinking maybe these rods belong to another type of application and the builder just threw them in from a common box of rods and never noticed them.
 

wishuwerehere82

Well-known member
Joined
Sep 6, 2003
Messages
2,314
Location
Rochester, NY
Corvette
Red '82 Coupe,Sebring Silver '98 Coupe
I thought there might be some that were upside down too so I pulled a few of them and they don't have any holes.

:confused

This could be the cause of my rocker knock. I was thinking maybe these rods belong to another type of application and the builder just threw them in from a common box of rods and never noticed them.

At times like this I reflect on the wisdom of others, as do you.
The ideal reasoner would when he has once been shown a single fact in all its bearing, deduce from it not only all the chain of events which led up to it, but also all the results which would follow from it.(Sherlock Holmes)

Let's see what a few others say. Offhand, I would say your deductions are sound.
 

black_81_vette

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Joined
Dec 1, 2002
Messages
295
Location
wisconsin
Corvette
black 81 corvette 4-speed
Those sound like corvair pushrods I have a few corvairs and they have a hole in the same spot for spring and rocker lubrication.Also the push rods are nearly the same length but taller. My suggestion is go get the proper push rods.
 

Kid_Again

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Joined
Jul 6, 2004
Messages
1,171
Location
NJ - Which exit you from?
Corvette
65 SB Roadster, 66 BB Coupe
GEEZ!!!! :W
 
Joined
Oct 7, 2006
Messages
295
Location
South Dakota
Corvette
76 Coupe
If those rods with the holes are longer, then the question is which is the correct length pushrod for this build to have the proper valve train geometry.
 

Whiplash

Well-known member
Joined
Nov 21, 2003
Messages
276
Location
New Jersey
Corvette
71 Kandy Burple Conv / 02 MY Z06
Had my mechanic look at the motor today due to all the pain I'm having. The "hole" actually turned out to be an imperfection in the rod. Several of them have what is actually a "dimple" but they don't go all the way through. The strange thing is the "dimple" is in the same place on all of the rods that have them. Rods are all straight but my valvetrain is toast.
 
S

Scooter76

Guest
The "dimple " is to signify the hardened end for use with guideplates.
My 95 formula with a LT1 , although did not come from the factory with guideplates, it did come with hardened pushrods. They all had the dimple on one end of the pushrod.
 

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