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Meassuring Push Rod lenght

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Phil66Mustang
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Meassuring Push Rod lenght

Post #1 by Phil66Mustang » Wed Feb 21, 2018 8:18 am

Hey,

If been searching on the web for hours now and still can't find the answer to it.
What is the correct way to meassure the correct push rod lenght with hydraulic lifters?

My set up is:
CI Aluminium Head
Yella Terra adjustable full Roller Rockers
Hydraulic Lifters

I also have a compcams adjustable push rod.

I don't have solid lifters with the same hight as the hydraulic ones i could use
Is there a way to pump up the Lifters so they wont collapse?

Regards
Phil

rwbrooks50
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Re: Meassuring Push Rod lenght

Post #2 by rwbrooks50 » Wed Feb 21, 2018 9:24 am

This thread may give some insight:

viewtopic.php?f=1&t=75922&p=587250&hilit=push+rods#p587250

Do a search "push rods" for more threads.

Rick

Phil66Mustang
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Re: Meassuring Push Rod lenght

Post #3 by Phil66Mustang » Wed Feb 21, 2018 10:09 am

Hey Rick,

I did read that thread but it's not answering my question.

This is what Bill (wsa111) is recommending to do:
"Why waste time, just get an adjustable pushrod from one of the cam companies & then adjust to the length that gives you the least sweep across the valve stem. At mid lift you should be close to the center of the valve stem. Then measure the length & order that demension from your pushrod vender."

From what i can tell this only works if you have solid lifters. The hydraulic ones i have are collapsing once i start to rotate the crankshaft. Therefore im not sure if the sweep marks across the valve stem will be the same once i get the engine running and the lifters pumped up.

Phil

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Re: Meassuring Push Rod lenght

Post #4 by pmuller9 » Wed Feb 21, 2018 10:22 am

You can take one of the old stock lifters and remove the plunger, clean out all the oil, remove the spring and install the plunger with something under it to shim the plunger to the height you need.
You may want the plunger .050" to .075" down from the retaining clip.

Is there any instructions indicating an initial setting for the adjusting screw on the rocker arm?
Example: On our adjustable rocker arms T & D wanted the screw to be 1 1/2 turns down from the top. (Different engine than yours)
We used that setting to measure the correct pushrod length.

When the rocker arm roller tip is half way down from the total valve lift, the imaginary line from the center of the roller tip to the center of the rocker shaft should be 90 degrees with the valve stem
If you mark the top of the valve stem with a black marker and roll the cam around a few times you should see a pattern that is centered on the valve stem tip.

If the pattern is off center towards the rocker then the rocker is sitting too low.
If the pattern is off center away from the rocker then the rocker is too high.

Phil66Mustang
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Re: Meassuring Push Rod lenght

Post #5 by Phil66Mustang » Wed Feb 21, 2018 11:32 am

that might work, i have to put something into it to raise the hight cause the new lifters are much higher then the old ones.
i dont have the instructions for the roller rockers, but i think i can get a good setting with the method you and Bill mentioned.

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Re: Meassuring Push Rod lenght

Post #6 by pmuller9 » Wed Feb 21, 2018 1:41 pm

This Is Important!!

There are two parts to this job.
The first part is to get the rocker height correct. You cannot find the correct pushrod lenght until this is done.

Since you have an adjustable pushrod you can set the valve lash to zero with the lifter bottomed out.
As described earlier run the valvetrain through with a couple of cam rotations using a black marker on the valve stem tip.
After removing the rocker, if the pattern is not centered on the valve tip then the rocker assembly will need to be shimed until the geometry is correct.
Shims or washers go under the bar that bolts to the head at each bolt hole.

Once the rocker height is correct, you preset the rocker arm adjusters to 1 1/2 turns from the top and then adjust the pushrod lenght for the proper lifter preload which should be between .050" and .075" making sure the lifter is siting on the heal of the cam.
You now have the correct pushrod length.

You will need to do this procedure for both the front and back rocker arm assemblies.

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wsa111
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Re: Meassuring Push Rod lenght

Post #7 by wsa111 » Wed Feb 21, 2018 2:09 pm

I hope you got the V-8 lifters which are oil through design to supply oil the rocker arms.
V-8 lifters are .150" higher than the non oil through stock lifters.
Make sure you block off the oil passage at the left side rear of the block. Tap & install a pipe plug. The head gasket is not capable to handle full oil pressure. I guarantee it will leak if you don't block off the oil passage.
67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, HEI dist. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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Phil66Mustang
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Re: Meassuring Push Rod lenght

Post #8 by Phil66Mustang » Wed Feb 21, 2018 2:19 pm

Since you have an adjustable pushrod you can set the valve lash to zero with the lifter bottomed out.
As described earlier run the valvetrain through with a couple of cam rotations using a black marker on the valve stem tip.
After removing the rocker, if the pattern is not centered on the valve tip then the rocker assembly will need to be shimed until the geometry is correct.


Do you mean to take the hydraulic lifters withoud making them solid? I could expend the adjustable pushrod to zero the valve lash and to fully collapse the spring inside the lifter. Would that give me accurate readings on the valve tip or should i modify the old hydraulic lifter to a soild one with same height?

Phil66Mustang
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Re: Meassuring Push Rod lenght

Post #9 by Phil66Mustang » Wed Feb 21, 2018 2:21 pm

I hope you got the V-8 lifters which are oil through design to supply oil the rocker arms.
V-8 lifters are .150" higher than the non oil through stock lifters.
Make sure you block off the oil passage at the left side rear of the block. Tap & install a pipe plug. The head gasket is not capable to handle full oil pressure. I guarantee it will leak if you don't block off the oil passage.


Hey Bill, i have the oil thru lifters and the oil passage is blocked properly.

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Re: Meassuring Push Rod lenght

Post #10 by pmuller9 » Wed Feb 21, 2018 3:15 pm

Phil66Mustang wrote:
Since you have an adjustable pushrod you can set the valve lash to zero with the lifter bottomed out.
As described earlier run the valvetrain through with a couple of cam rotations using a black marker on the valve stem tip.
After removing the rocker, if the pattern is not centered on the valve tip then the rocker assembly will need to be shimed until the geometry is correct.


Do you mean to take the hydraulic lifters withoud making them solid? I could expend the adjustable pushrod to zero the valve lash and to fully collapse the spring inside the lifter. Would that give me accurate readings on the valve tip or should i modify the old hydraulic lifter to a soild one with same height?

Yes, usually there is a ledge inside the lifter body that will not allow a collapsed lifter to smash the spring closed.
I would still use the old stock lifter that has had the oil clean out of it so I know the plunger is sitting solid on the bottom.

At this point you are only interested in opening the valve from zero lash to full open.
It won't make a differce if it is being done with a collapsed lifter and longer pushrod or extended lifter with a shorter pushrod.
The rocker arm doesn't see the difference.The geometry is only based on the relationship between the rocker pivot height, valve tip height and valve lift.
Once the rocker height is set then the pushrod lenght based on that height can be determined.

This is our procedure for T&D rocker arm assemblies that have a cradle with shaft mount rockers.
The only difference is we are using solid roller lifters so instead of hydraulic lifter preload we have valve lash to figure in when determining pushrod length.

Hope this makes sense

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Re: Meassuring Push Rod lenght

Post #11 by wsa111 » Wed Feb 21, 2018 9:15 pm

Phil66Mustang wrote:
I hope you got the V-8 lifters which are oil through design to supply oil the rocker arms.
V-8 lifters are .150" higher than the non oil through stock lifters.
Make sure you block off the oil passage at the left side rear of the block. Tap & install a pipe plug. The head gasket is not capable to handle full oil pressure. I guarantee it will leak if you don't block off the oil passage.


Hey Bill, i have the oil thru lifters and the oil passage is blocked properly.

Just making sure.
I wonder if Clay Smith Cams made CI's pushrods?? They would have the pushrod length you need.
But you are doing it correct for the camshaft you are running.
67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, HEI dist. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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Phil66Mustang
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Re: Meassuring Push Rod lenght

Post #12 by Phil66Mustang » Thu Feb 22, 2018 3:22 am

pmuller9 wrote:
Phil66Mustang wrote:
Since you have an adjustable pushrod you can set the valve lash to zero with the lifter bottomed out.
As described earlier run the valvetrain through with a couple of cam rotations using a black marker on the valve stem tip.
After removing the rocker, if the pattern is not centered on the valve tip then the rocker assembly will need to be shimed until the geometry is correct.


Do you mean to take the hydraulic lifters withoud making them solid? I could expend the adjustable pushrod to zero the valve lash and to fully collapse the spring inside the lifter. Would that give me accurate readings on the valve tip or should i modify the old hydraulic lifter to a soild one with same height?

Yes, usually there is a ledge inside the lifter body that will not allow a collapsed lifter to smash the spring closed.
I would still use the old stock lifter that has had the oil clean out of it so I know the plunger is sitting solid on the bottom.

At this point you are only interested in opening the valve from zero lash to full open.
It won't make a differce if it is being done with a collapsed lifter and longer pushrod or extended lifter with a shorter pushrod.
The rocker arm doesn't see the difference.The geometry is only based on the relationship between the rocker pivot height, valve tip height and valve lift.
Once the rocker height is set then the pushrod lenght based on that height can be determined.

This is our procedure for T&D rocker arm assemblies that have a cradle with shaft mount rockers.
The only difference is we are using solid roller lifters so instead of hydraulic lifter preload we have valve lash to figure in when determining pushrod length.

Hope this makes sense


Now that you mentioned it, it makes a lot sense. The rocker arm won’t see the difference of the pushrod length. In that case I think I will use the installed hydraulic pushrods. That makes it easier and I don’t have to take off the head again and again.

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Re: Meassuring Push Rod lenght

Post #13 by Phil66Mustang » Sat Mar 17, 2018 8:43 am

finally got the chance to meassure the pushrod lenght.

i used the instructions from the tech archive about the inital valve adjustment to mesassure the lenght

Start by rotating the crank clockwise, while your watching the valves in the #1 cylinder. When the exhaust valve begins to move downward, stop rotating the motor and adjust the intake valve to the proper lash. Next, continue rotating the engine clockwise, until the intake valve reaches maximum lift and is almost all the way back down, then stop and adjust the exhaust valve. Continue adjusting the valves in each cylinder, until they are all adjusted to the proper lash.


I got these lenght without any preload

Cylinder 1
Int: 7,99
ext: 7,97
Cylinder 2
Int: 7,98
ext: 7,96
Cylinder 3
Int: 7,98
ext: 7,98
Cylinder 4
Int: 7,99
ext: 7,94
Cylinder 5
Int: 8,00
ext: 7,96
Cylinder 6
Int: 7,99
ext: 7,98

8.000 pushrods should be the right ones, right?

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Re: Meassuring Push Rod lenght

Post #14 by pmuller9 » Sat Mar 17, 2018 9:47 am

Did you get a nicely centered patern on the valve tips when you checked for proper rocker height?

The total pushrod lenght should include the lifter preload distance with the rocker pushrod adjusting screw set so there is adjustment in both directions.
Do the rocker screws bottom out in the rocker when you try to screw them outwards?

Phil66Mustang
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Re: Meassuring Push Rod lenght

Post #15 by Phil66Mustang » Mon Mar 19, 2018 12:28 pm

the patern is good, i cheked the lenght with the rocker adjustment screw screwed in half way as recommendet in the rebuild videos from echo1955.

after that i did check again with the screws screwed in 1 1/2 turn as you recommendend.

I didn't checked them all but i got these lenght.
According to these meassurements i thought the 8.075 pushrods should fit best since there's plenty of room for the screw to go down.

Cylinder 1
Int: 8,100
ex: 8,075
Cylinder 3
Int: 8,088
ex: 8,100
Cylinder 4
Int: 8,100
ex: 8,063

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Re: Meassuring Push Rod lenght

Post #16 by pmuller9 » Sun Mar 25, 2018 1:54 pm

Phil66Mustang wrote:the patern is good, i cheked the lenght with the rocker adjustment screw screwed in half way as recommendet in the rebuild videos from echo1955.

after that i did check again with the screws screwed in 1 1/2 turn as you recommendend.

I didn't checked them all but i got these lenght.
According to these meassurements i thought the 8.075 pushrods should fit best since there's plenty of room for the screw to go down.

Cylinder 1
Int: 8,100
ex: 8,075
Cylinder 3
Int: 8,088
ex: 8,100
Cylinder 4
Int: 8,100
ex: 8,063


8.075" looks good.

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