Congrats on the new skill!
I have never done that before, but am familiar with the theory. I have only used GM castings.
I have never done that before, but am familiar with the theory. I have only used GM castings.
New guy 79 factory 4 speed wagon.
- Thread starter Mighty
- Start date
A final check is to color the top of the valve stem with a Sharpie. Put the adjustable pushrod and rocker arm back on. Then, turn the engine over a full revolution. Remove the rocker arm and confirm the wear pattern is centered on the tip of the valve stem.
I took your advice but it was with a new $150 set of chrome moly push rods I got. My measurement came out to 7.8125 but could only get a 7.8” inch push rod. Colored the top of the valve with a sharpie and spun the motor over twice. Anything stick out or look off? Maybe a wee tiny bit toward the top of the valve? Could that be where I’m missing the additional .0125?
I think you did a super job and are close enough to perfect as you are going to get.
For reference, what type of pattern do you get with the original pushrods?
For reference, what type of pattern do you get with the original pushrods?
Tried to hold the light as best I could go pick up the two marks. One on the left is the new push rod, the one on the right is the original ones. Pretty close I think. Measuring with a ruler on beat up work bench I came up with ~7.75 inches for the original ones but searching online shows 7.794.
The one on the right doesn't look like the roller sat on the valve squarely, so too hard to tell the pattern.
It was from oil that’s still sitting in/on the rocker. If I do the fuel lines on my truck tomorrow I might stop at the local orileys because they have a bunch of pushrods in stock. I might buy a single 7.84 and run the test again and see what I come up with just for the heck of it. I’ve had 3 people now tell me it’s fine. I guess I see why people use a caliper to measure instead of an old ruler. Jegs told me they would let me switch the 7.8 pushrods out with longer ones without having to pay the $15 restocking fee if they didn’t work luckily. I’m probably just over thinking it. Is it true that if the rocker sits too high on the valve you can lose some of your cam lift?
You want the pattern in the center of the stem. Too much on either extreme means excess side force on the stem...improper geometry. I imagine the improper geometry will cause excess guide wear. If the pattern is not centered, there will be a loss of lift, but not likely enough to worry about.
The pattern on the new pushrods looks good to 3 people. I just thought it would be interesting to know if the stock pushrods produced a pattern that was as good if not better than the new pushrods.
The pattern on the new pushrods looks good to 3 people. I just thought it would be interesting to know if the stock pushrods produced a pattern that was as good if not better than the new pushrods.
Ill run the test again with the original push rods and probably buy a single slightly longer one to see if/how much it changes
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