Rocker to valve stem contact location
 

I put on a head with a steel head gasket (not torqued down) with good rockers and the right pushrods. I set the valve lash after putting some ink on the valve stem then turned it over through a full valve event. Both intake & exhaust had a pattern to the outside of center.

Does anyone think it's possible that the contact might move to center after the head gasket is torqued? I estimate the head would go down about .004" with the gasket compressed.
Any ideas?
New Manley SS valves that are the stock height. I may have lost about .002-.003" from the valve job. So it's possible that the valve is positioned as much as .007" higher then spec.



Verne:hmmm:

Are they roller rockers or stamped steel? You can't really check stem pattern on stamped steel rockers.

They're stamped steel. Stock OEM. They still do leave a contact path and it's not centered very well.



Verne

I don't see any way the pattern moves by torquing the head.

" pattern to the outside of center" = bad news (eventually) in my humble opinion.

"good rockers" is very subjective. New rockers are cheap insurance. I learned this the hard way. Is this a 409?

This is a 409 Lynn,
Torquing the head down moves the valve down a bit. With the same pushrod length that will pull the rocker tip further inboard.
I have new rockers.


My concern about the swath being outside of center was the reason for my initial question.


Verne

This is a good video that clearly explains the relationship and geometry of the valve train pieces. https://youtu.be/o5is9BsH5OU this should get your rocker in the right position after you watch and understand. To address the non-torqued head gasket. All , ALL clearances and adjustments should be done with the head torqued. Use a used head gasket if you are not ready to torque down a head, providing the used gasket is the same compressed height as the new ones you will use.

Aim for minimum sweep. Better to have it off center and a narrow contact patch than centered with a wide contact pattern.

That's a fine video Bentley, but I can't use that method with OEM ball rockers. I'm also using NOS OEM non-adjustible pushrods.


Verne

With OEM rockers and stock length pushrods, you can't adjust it anyway (unless you change valve height or cam base circle). Seems like you might just have to let it fall where it falls. A little off center is not detrimental if the sweep is minimal.

I think I misunderstood your initial post. I was thinking side to side, meaning if I look at the valve stem from the side of the car, the pattern is slightly to my left or my right. I fully agree that the pattern in and out could change after torquing the heads. Only way to find out is to torque it down.

Slightly off center (in and out, not side to side) would not worry me. Ideally, you want it right in the center. I have a couple of adjustable test push rods that I use to dial in the perfect length, then go hunting for push rods. Of course, I am guessing the 409 doesn't have the same dizzying array of push rods available as the SBC.