Shortening Pushrods?

[wedge5]

I milled my heads down from 75cc to 65cc. It was mentioned that I may need to get new pushrods because the others will be to long. I just bought new pushrods last year for the 75cc heads; can I have these shortened or would it be better to get new ones. These are basically new, they have no road/track miles on them just garage time.

 

[67 coronet]

if you have adjustable rockers you can adjust that extra length out.

 

[67 B-body]

How many thousanths did they mill off to get that CC?

 

[moparpoor]

if you have adjustable rockers you can adjust that extra length out.

If they were measured correctly the first time.Their should only be one full thread showing.Only allowing for a few thousandths adjustment.This is especially critical when spring pressures are high.To cut those heads down to the 65cc they took a hunk of meat off them.

 

[67 coronet]

If they were measured correctly the first time.Their should only be one full thread showing.Only allowing for a few thousandths adjustment.This is especially critical when spring pressures are high.To cut those heads down to the 65cc they took a hunk of meat off them.

i have adjusted rockers with up to 3+ threads showing with no illeffects.(around 1/16 of an inch)spring pressure was plenty high on them as well.what would be the point of an adjustable rocker if cant adjust it?if presure is super high,then ya,get custom hardened pushrods.also,it is more then likely,your intake will have to be custom milled to fit in the valley as well.

 

[moparpoor]

The pushrods will be too long!What are you going to do,run the cup up into the the rocker arm?:eusa_think:

What kind of spring pressure were you running with three full turns out?Roller or flat tappet cams.Yes you can run three turns out on smaller cams with lower spring pressure.It also affects pushrod angle at full lift.It tends to put the pushrod close to the opening if not touching.It will cause early adjuster wear and possible failure.More turns out the more the pushrod pushes on the edge of the cup than the center at full lift.When pressures are at their greatest.

 

[67 coronet]

when it comes down to it wedge,you will need to install your valve train to find out where you are at.then you can figure out where to go from there.

 

[wedge5]

Ok here is another ?

My motor is together. I still need to put rockers on. What do I need to do to check for the proper length pushrods? Am I making any sense?

 

[moparpoor]

Adjustable pushrod.They sell them or you can make one.

 

[1stBxMopar]

Have you checked your valve to piston clearance to make sure you still have enough room?
Just my two cents........

 

[67 coronet]

Have you checked your valve to piston clearance to make sure you still have enough room?
Just my two cents........

i was gonna metion that,thanx.if you choped that much off your head,you may have contact inside the cylinder,at full cam lift,between the valve and the top of the piston.there are a few way to check,try and find it on the internet,otherwise it will take a good amount of expaining here.

 

[Budnicks]

Call Smith Brothers Push Rods, they sell the adjustable push rods you need to check them properly, you want the rocker tip {valve side} to stay over the "center of the valve stem/tip" as much as possible, like mentioned before "you should have checked your piston to valve clearance", before installing the head permanently/torquing it down completely, just to be safe... How much camshaft lift ??, what was your piston to valve clearance before shaving the heads ??, how much material was removed from the head to get the 65cc ?? & was it a flat shave/mill ?? or angle milled ?? or what ??, more info needed, to give a good recomendation... good luck & Happy Moparing

 

[wedge5]

You guys went way overboard on this question. All I asked was can pushrods be shortened. I just forgot about the pushrods when I did this. I am getting an adjustable push rod to check for proper length. I was just wondering when I get my length can I have the ones I am have shortened? Hence the ?

Thanks for the help though, it made me get an adjustable pushrod.

 

[Budnicks]

We do tend to be a batch of over thinkers here, don't we ??...LOL... Yes you can shorten the push-rods, but it's a damn hassel, as long as you can get the cupped ends pressed off, with out damaging any of them or just buy new ends... Call Smith Brother's Push-Rods it's probably a better idea... Unless you have access to a lathe or wet saw to cut the old push-rods to exact clean cut to proper lengths {square 90 degree cuts}, then press the new/old caps/cups back on... Just my opinion, I've seen too man "trying to save a few bucks" type projects, go really bad, because of bad push-rods or breakage from stuff coming apart, trying to save a few bucks...

 

[moparpoor]

You guys went way overboard on this question. All I asked was can pushrods be shortened. I just forgot about the pushrods when I did this. I am getting an adjustable push rod to check for proper length. I was just wondering when I get my length can I have the ones I am have shortened? Hence the ?

Thanks for the help though, it made me get an adjustable pushrod.

You are correct!!!Then again you have spent how many thousands of dollars to build this motor?One little mistake can turn it into many thousands of pieces.I truely hate to see people waste money on simple mistakes.

 

[MarPar]

Lurkin' and learnin'

You are correct!!!Then again you have spent how many thousands of dollars to build this motor?One little mistake can turn it into many thousands of pieces.I truely hate to see people waste money on simple mistakes.

replies like that is what makes this the best damn board on the intranet!!!!

 

[wedge5]

Great Advice! Looks like I have some work to do,Later.

 

[MarPar]

Great Advice! Looks like I have some work to do,Later.

hey wedge just remember....

:worthless_thread:lol!! later!

 

[bigmanjbmopar]

Yeah when did we start letting peeps get away with out the engine ****? dam shame, the only reason I show up here is for the ****....

Get cracking with the pics man!!