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383 Pushrod length w/adj rockers

superbeedave

superbeedave

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Hey Guy's,
Can you guy's tell me what length of pushrod I need for 383 with hydraulic cam and crane adjustable rockers? i have had these for years and the pushrods I have are 8.250 which Mancini Racing told me to use. But at every cold start up after sitting for more than a day I have valve train noise which goes away after 10 or more seconds. I believe I need a taller pushrod just from reading and seeing all different lengths. There are 8.290, 8.490, 8 5/8. Thanks Dave!
 
You are better ordering an adjustable push rod and measuring with your set up. Then order what you need.
 
I put a set of adjustable rockers on my 383 a couple years ago. Found out that there really isn't an exact length for all. As Texas.. said, you'll need an adjustable pushrod to measure the length. Once you get your rockers on and get geometry right, measure the pushrod and then order a set making sure you get the correct ends for your rockers. Good luck. If you need a couple ideas where to get custom pushrods, let us know.
 
I kind of figured that I would have to do. I just have never done it before to know what the heck I am doing! Anyone like
to explain to me how to do that? Can I do it the way you mark a line on the push when your at zero then go 1/2 to 1 turn with the screw and then mark another line on the rod and the distance should be .04-.06? Thanks, Dave
 
image.jpeg
Here's a pic of the adjustable pushrod to measure and an actual pushrod from my 383.

When I did the measurements, I had a guy with me who knew geometry of the pushrods to rockers and knew valve lash. I was a newbie at it all too so I was good to go putting in the measuring pushrod but that was it.

With the adjusting rod, you put the ends in that match up with your rockers and lifters. Once in,
Adjust the ends to make the pushrod the correct length. This is where someone who knows can and should help. Once determine right length, make sure you got the right ends and then find a place to order. That's it in a nutshell, not hard but if you are like I was, it was intimidating until I did it a couple times. Do a search for adjusting roller rockers. Plenty of stuff out there.

Here's a link to a site where it explains about ordering pushrods. I have purchase a few sets from these guys and have been perfect! Good luck!

http://www.4secondsflat.com/smith_brothers_custom_pushrods.htm
 
Xp29h said:
View attachment 356505 Here's a pic of the adjustable pushrod to measure and an actual pushrod from my 383.

When I did the measurements, I had a guy with me who knew geometry of the pushrods to rockers and knew valve lash. I was a newbie at it all too so I was good to go putting in the measuring pushrod but that was it.

With the adjusting rod, you put the ends in that match up with your rockers and lifters. Once in,
Adjust the ends to make the pushrod the correct length. This is where someone who knows can and should help. Once determine right length, make sure you got the right ends and then find a place to order. That's it in a nutshell, not hard but if you are like I was, it was intimidating until I did it a couple times. Do a search for adjusting roller rockers. Plenty of stuff out there.

Here's a link to a site where it explains about ordering pushrods. I have purchase a few sets from these guys and have been perfect! Good luck!

http://www.4secondsflat.com/smith_brothers_custom_pushrods.htm
Click to expand...
Thank you, good stuff to learn here! I have already done a search on how to do this procedure but I'm not sure
what is being measured exactly. Does the lift of your cam ever come into play on this measurement? Shouldn't the travel of the pushrod
from the valve being closed to it being fully open tell you what the lift is?
 
I do know that I have close to 3 threads showing on the rocker on the push rod side. That would tell me they are too short
so last night I was thinking maybe I need about 8.290 length which 440 source sells.
 
Invest in the pushrod checking tool. I tried guessing and it didn't work out. Bought the checking tool. Set it, removed and measured the lenth, called Smith Brothers. Done deal...
 
So I am just removing a push rod adjust the checking tool to the same length as the push rod then insert the tool in and turn in the screw on the rocker until I have zero lash which is when I feel a drag or is it the up and down technique of the push rod? Then take the checking rod back out and measure the length. Am I close?
 
You use the checking tool in place of the pushrod. Make sure you're on the lowest part of the cam for that valve. Screw the pushrod out, to take up the slack, without pushing the cup in the lifter down. On the Crane rocker, which I have, leave one thread showing during your measuring.
Do several valves to get an average measurement. Also you need to measure your lifter cup and rocker ball for ordering.
When you receive your new pushrods, take out the slack, then turn the adjuster 1/2 of a turn. That will compress the lifter cup/piston .020. That's your adjustment.
Just a question, is that the adjustment that you are useing, 1/2 turn after taking out the slack, without pushing the lifter piston down?
 
khryslerkid said:
You use the checking tool in place of the pushrod. Make sure you're on the lowest part of the cam for that valve. Screw the pushrod out, to take up the slack, without pushing the cup in the lifter down. On the Crane rocker, which I have, leave one thread showing during your measuring.
Do several valves to get an average measurement. Also you need to measure your lifter cup and rocker ball for ordering.
When you receive your new pushrods, take out the slack, then turn the adjuster 1/2 of a turn. That will compress the lifter cup/piston .020. That's your adjustment.
Just a question, is that the adjustment that you are useing, 1/2 turn after taking out the slack, without pushing the lifter piston down?
Click to expand...
No, It is more like 1 1/2 - 2 turns.
 
superbeedave said:
No, It is more like 1 1/2 - 2 turns.
Click to expand...
Thats more than likely your problem.
Pushing the lifter's piston too far will bleed them down when sitting. Plus it might be real risky on the valve train and preformance.
You stated you had three threads showing. That's what made me ask. Do the 1/2 turn adjustment and I'll bet you'll be fine with the pushrods that you have...
 
khryslerkid said:
Thats more than likely your problem.
Pushing the lifter's piston too far will bleed them down when sitting. Plus it might be real risky on the valve train and preformance.
You stated you had three threads showing. That's what made me ask. Do the 1/2 turn adjustment and I'll bet you'll be fine with the pushrods that you have...
Click to expand...
I started out with the 1/2 turn was a little noisy when hot then to 1 turn then 1 1/2 and that made it quiet. They have always been noisy when starting up cold after sitting a couple days.
 
You have to find a checking pushrod that falls into you range of measuring. There's different ones.

What lift cam are you useing?
 
I don't know what to tell you. To me, your pushrod length seems to be about right if you were adjusting to 1/2 turn.
Are you useing a heavy duty, high pump lifter? A heavier than stock valve spring?
 
khryslerkid said:
I don't know what to tell you. To me, your pushrod length seems to be about right if you were adjusting to 1/2 turn.
Are you useing a heavy duty, high pump lifter? A heavier than stock valve spring?
Click to expand...
The lifters and springs were matched with the cam. Spring installed height is 1.900 if that means anything.
 
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