Correct pushrod length

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sazanata

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Hello,

I am in the process of instaling crane gold roller rockers in my 318 LA (it is 1969 engine). I removed the original rocker arms and pushrods. The pushrods measured 7.500 inches, the stock lenght, as I have hydraulic flat tappet lifters and my heads have not been modified. Car runs pretty good with them. 10 years ago, I bought the crane rockers with ball/cup pushrods at summitracing. They told me that the pushrod length for me was 7.330, but it is not. Yesterday I installed everything and when adjusting the valves, I put cylinder 1 in TDC compression, went for the intake valve on cylinder 2 and the cup of the pushrod was almost touching the rocker, even without the adjusting screw. I read in many places that 2 threads of the screw shoud be visible under the rocker and for this I need a pushrod lenght of a little less than 6.900 inches. Can someone please help me?

Thanks a lot.
Salvador
 
What hydraulic lifters are you using?.......

Get a pushrod checker....it has an adjustable end that allow you to get the correct length....

but in generally the 7.33 is correct unless the seat of the lifter is higher up....as in AMC lifters.
 
And buy a 5/16" ball bearing so you don't have to guess about the cup.
 
70aarcuda said:
What hydraulic lifters are you using?.......

Get a pushrod checker....it has an adjustable end that allow you to get the correct length....

but in generally the 7.33 is correct unless the seat of the lifter is higher up....as in AMC lifters.
Click to expand...

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Now I am much more confused. I am not sure about the lifters, they came with the car, but if the pushrods that were in the engine with the stock rockers were 7.500 in lenght, the lifters must be stock, right?

This is the first time I adjust valves, maybe I am doing something wrong. I just followed the instructions at hughes site: Put piston 1 in TDC compression and adjusted the intake valve on cylinder 2 and exhaust on 8. As the pushrods are almost touching the rocker, there was very little play with it without the adjusting screw. I turned the screw by hand until it touched the pushrod and there was no play in the rocker. Then I gave another half a turn. At the point when there was no play at the rocker, I could still turn the pushrod with my finger, easily. Even after the half a turn. Maybe I did not understand it correctly...
 
A lot of variables can change the push rod length. Cam base size, Lifter, block and head milling, shaft locations, rockers geometry, and valve length are all a factor.

Get an adjustable checker and set it up and also verify your geometry.
 
Correct 7.50 is stock length with non adjustable rockers..just like 7.33 is correct.
Are the shafts bolted down
 
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