push rod ?

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so now i have looked up all the part numbers and looked at push rods in hand and the three motors( two 318s and one 360) i have in their stock form all use the same push rod and its roughly 7.5 inches long.

the ones in the 360 i bought are only about 7 1/4 so they are about 1/4 shorter than stock length. Thats the problem with working on stuff you did not put together urself ughhh.

everything in the motor looks to be pretty new and stockish but what can you tell just by looking right lol. and i have no clue on the cam either but why would somebody put shorter push rods in ?? because of cam choice as it has the stock type non adjustable rocker arm shaft and rocker arms.
 
so i suppose i am just going to finish putting it together with the parts that came with and in the motor and see how it goes. Because they ran it in a 74 charger and worse case scenario it blows up and im out 400.00 bucks less the new motor stand and other aftermarket reusable stuff i got with it
 
1970-dart said:
went to Napa and looked some stuff up and found ( no surprise) they list the non oiling with the ball ends like the newer ones( the four different on each side) i have. they list all same lengths/sizes and part numbers for the 68/318 74/318 and 85/360 i have so i will look at all i have and make up the best matching set of non oiling push rods that i can.


thanks for all the help folks
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What? No special "Australian" ones?
 
No way to be sure, but the shorter ones are probably for adjustable rocker arms. I'd make sure you have 16 of the correct length. Too short and they might even be loose enough to disengage from the rocker arms. That wouldn't be pretty on a running engine.
 
69_340_GTS said:
No way to be sure, but the shorter ones are probably for adjustable rocker arms. I'd make sure you have 16 of the correct length. Too short and they might even be loose enough to disengage from the rocker arms. That wouldn't be pretty on a running engine.
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they are not adjustable rockers arms so there is no other reason that shorter ones would be used other than the people that put them in are stupid lol
 
In the pictures, the older ones look like they fit the rocker arms better.
I would pull a stock set out of a LA engine, I would not trust the dimensions you are getting from parts stores.
 
sireland67 said:
In the pictures, the older ones look like they fit the rocker arms better.
I would pull a stock set out of a LA engine, I would not trust the dimensions you are getting from parts stores.
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I did two different motors and they are ( as close as I can get with a oid tape measure ) 7.51??? just like both parts stores and Rock auto said.

And even the older ones in the picture are the same length and shorter thab the ones in my other two motors.
 
would oil through be a big problem I think I have oil through ones with a solid cam but the lifters have a small hole through them so I think they need to be that way
 
dvav said:
would oil through be a big problem I think I have oil through ones with a solid cam but the lifters have a small hole through them so I think they need to be that way
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That was my first question and it seems they can be but don't have to be nor are from the factory. My problem found through all this research us that they seem to be shorter than what they are supposed to be
 
As to the short pushrod question.Theres only one reason for shortties. Machining stack up.
If the decks were machinerd for zero decks, and the heads were machined for compression,and maybe some custom valve work, then custom pushrods would be required.
In your case being as they are .250 shorter, thats an awful, awful,lot of cutting.By page, 3 I cant recall if you did a mock up.
Ok, I reread the thread, and see no mock-up
I would order an adjustable push rod and mock up for a geometry check, and then compare the needed length with the provided length, and see how close they are.Order if you need.
And once again, if the balls dont fit the cups, THROW them away.Quit speculating/fixating on the why of it.
 
so i searched push rod lengths and the writeup and video on using adjustable push rod to check for proper length. well i dont have and could not get my hands on a adjustable push rod over the weekend. so i figured i would follow the process with my current push rods but i had four on each side did not sit perfect in the cups of the rocker. I took one of them that did and went to napa and matched it up to get the correct size/length for my test

i figured doing the test with my current parts would tell me if it was done right and i was good or needed to get an adjustable rod and start from scratch. i cleaned and marked the top of each valve attached and tightened down the valve train and rolled the motor over and watched the valves open and close 5 times.

i pulled the valve train off and bingo the wear mark was right across the center so they must have milled the heads/block and i think i should be good.

thanks for all the help
 
AJ/FormS said:
Good, except for the big-balled rods, which dont fit the cups..
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i had four on each side did not sit perfect in the cups of the rocker. I took one of them that did and went to napa and matched it up to get the correct size/length for my test
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guess you missed that part lol


thanks so much for ur help along the way it is greatly appreciated
 
i assume if i had used the big ball ones that the mark would have been leaning to show them being a tad long because they did not sit all the way in the cup
 
The 2nd paragraph in post#62 says you were gonna do the test with current parts, which I assumed were the 7.25s.
So,yeah Im confused. Did you perform this test with a 7.5 inch, small end, rod. And are now going to order the rest as 7.5s?
Or are the 7.25s the right ones? In which case the big-balled ones have to be discarded.
 
AJ/FormS said:
So,yeah Im confused. Did you perform this test with a 7.5 inch, small end, rod. And are now going to order the rest as 7.5s?
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no i went and matched up the length rod( the shorter one) that came with the engine but with out the big ball ends and preformed the test.

i guess it could be confusing because said used current part but changed out the 8 (4 each side)rods that did not sit proper in the cups with ones i matched up at Napa. sorry for that confusion
 
my motor came with all the same length rods but 4 on each side had the big ball ends. so i took of the(non big ball ends) rods that came with the engine to napa and matched it up.

then i had all same length rods and none with big ball ends and they all fit in the cups good and then did the test
 
Just because the sweep on the valve stem is right, doesn't mean the length is correct. You want to make sure the lifter preload is in spec. How do you know yours is?
 
mopowers said:
Just because the sweep on the valve stem is right, doesn't mean the length is correct. You want to make sure the lifter preload is in spec. How do you know yours is?
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i dont lol and i knew if there was something else i would miss somebody would get me in the right direction so thanks and back to the drawing board
 
Yup the pushrod length and sweep test are usually performed at the same time.
We use the adjustable pushrod. And we need to prevent the hydraulic lifter from bleeding down. First, on the cylinder we are going to check,the valve springs are removed, and much softer checking springs are installed.Alternatively(cause I hate RnRing springs) a Checking Lifter can be made up. This is nothing more than a matching lifter with the guts removed and a spacer made up and installed under the cup to simulate the preload you are wanting to run.I built mine decades ago.After all these years maybe somebody is making these.
As to preload,most guys run about .020 to .040. I have adjustable rockers so run just barely enough to keep things quiet.Then at some higher rpm those lifters may pump up and go solid. If/when they do, its no biggy. I get a rough idle for a couple of seconds, but no internal damage. But,when running non-adjustables its better to run closer to .040inch preload, so the lifters will stay quiet for the life of the lobes.
Once the set-up is ready, you put the cam on the base circle, and install your adjustable push rod, and lengthen it to zero lash. Then you do the sweep-test, to see where youre at.If that comes out 100%, then you simply measure that pushrod and record the number and its location. Then you repeat the test on the other valve, and record the measurement and location.
Now if the heads or decks have been milled its a good idea to measure at least one valve at each corner.Then average the corner measurements out. If things get too close to the minimum, you may have to make a judgement call, and arbitrarily add some preload. Otherwise one day your engine will develop a lifter-tick.
Finally you evaluate the numbers,and order the correct one-size-fits-all pushrods.
In a heavily machined combo the ideal pushrod lengths might be all over the place.In this case it might be preferable to run adjustables in every single location.With modern equipment, machining is much more precise than in years gone by, and it would be a sad day if you had to put adjustables in every location,today.
 
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