Rocker Adjustment

-
Wagon of Death

Wagon of Death

Aussie Barracuda Fisherman
Joined
Aug 30, 2009
Messages
120
Reaction score
34
Location
Brisbane,Aust
So Ive managed to lose my cam card and am not sure what I should be setting these rockers at...New engine,well its got 1000 miles on it now, and they are just starting to get a bit noisy, so time for a look at..
Its a Crane 694571, Ive google searched for a while and can find all the specs, lift , duration etc but nothing on the recommended rocker gap...I know its not what the factory spec , any ideas how I would get this info? Id like to look at this today..
 
Last edited:
Disregard. Didn’t know running solids.

CD059BC8-A330-4F6A-897E-00CD3ED333EF.jpeg
 
Turns out Im mistaken...Hyd lifters...Ive scoured the Crane sites trying to find this spec with no luck...as you can see on the page Dubob posted...no info...
 
So we need to know, if it's a hydraulic lifter cam do you have adjustable rockers? If so, zero lash an 1/2 turn usually does the trick.
 
toolmanmike said:
So we need to know, if it's a hydraulic lifter cam do you have adjustable rockers? If so, zero lash an 1/2 turn usually does the trick.
Click to expand...
Yessir ,hyd lifter...and adjustable rockers...so zero lash is adjust till there is slightest tension on the pushrod, then 1/2 a turn? Ive always only ever used feeler guages at the rocker tip
 
Wagon of Death said:
Yessir ,hyd lifter...and adjustable rockers...so zero lash is adjust till there is slightest tension on the pushrod, then 1/2 a turn? Ive always only ever used feeler guages at the rocker tip
Click to expand...
Yes. You could probably adjust with a thin feeler gauge and almost a half turn. Hydraulics are pretty forgiving.
 
Wagon of Death said:
So Ive managed to lose my cam card and am not sure what I should be setting these rockers at...New engine,well its got 1000 miles on it now, and they are just starting to get a bit noisy, so time for a look at..
Its a Crane 694571, Ive google searched for a while and can find all the specs, lift , duration etc but nothing on the recommended rocker gap...I know its not what the factory spec , any ideas how I would get this info? Id like to look at this today..
Click to expand...

Increased wear is causing more noise. Is it just from breaking in? Or is something going wrong? Inspect your rocker arm assembly for unusual wear and/or signs of trouble while your in there.

I just went through the later with my motor, and my problems root cause was improper spring pressure for several reasons. Had to get at the root of the problem and rebuild everything from there. It wasn't cheap or fun. I hope your issue is from the initial break-in wear.
 
So how did you find out which pushrods to use ? I'll soon be changing a 273 to Hydraulic Flat Tappet and understand that the pushrod length is different.
 
I can't remember the length off hand. Hopefully somebody will stop by and let us know the length or the part number.
 
toolmanmike said:
I can't remember the length off hand. Hopefully somebody will stop by and let us know the length or the part number.
Click to expand...
I KNOW that MANY have made this change but I can't seem to find a definitive answer to this question. We are going with a MILD cam so we are NOT looking for custom chrome-moly pushrods. Just a stock replacement in the proper length.
 
Lee Prim said:
I KNOW that MANY have made this change but I can't seem to find a definitive answer to this question. We are going with a MILD cam so we are NOT looking for custom chrome-moly pushrods. Just a stock replacement in the proper length.
Click to expand...
I'll se if I can find it.
 
use 318 hyd lifters but pushrods would be different for adjustable rockers
BVVC there are early and late lifters and pushrods with different diam lifter cups and tips (at least for BBM)
also the later AMC/Magnum lifters have a different height- they are widely sold for most everything MOPAR now
if your heads have been milled, or block decked, the aftermarket gasket may even things out
since you have adj rockers make sure the lifter ball is not way out from the rocker when adjusted
there are early adjusters which we adjusted with three threads showing but these had a short neck between ball and threads
later adjusters have a long neck
bottom line is tha you may need custom pushrods anyway unless you can find some in a length chart
 
Wyrmrider said:
use 318 hyd lifters but pushrods would be different for adjustable rockers
BVVC there are early and late lifters and pushrods with different diam lifter cups and tips (at least for BBM)
also the later AMC/Magnum lifters have a different height- they are widely sold for most everything MOPAR now
if your heads have been milled, or block decked, the aftermarket gasket may even things out
since you have adj rockers make sure the lifter ball is not way out from the rocker when adjusted
there are early adjusters which we adjusted with three threads showing but these had a short neck between ball and threads
later adjusters have a long neck
bottom line is tha you may need custom pushrods anyway unless you can find some in a length chart
Click to expand...
My point is WHY ? This mod has been done a BAZILLION times. The difference in height between the hydraulic and solid lifter cup is a KNOWN dimension. If I am simply changing from solid to hydraulic, ANY manufacturer SHOULD know EXACTLY what I'm looking for. I even saw one thread where there was disagreement as to where to take the measurements from. Some said total length while others said center of ball to center of ball. This is NOT magic. It's a pushrod with cup at one end, ball at the other end, this much longer than stock. How hard can that be ?
 
Lee Prim said:
My point is WHY ? This mod has been done a BAZILLION times. The difference in height between the hydraulic and solid lifter cup is a KNOWN dimension. If I am simply changing from solid to hydraulic, ANY manufacturer SHOULD know EXACTLY what I'm looking for. I even saw one thread where there was disagreement as to where to take the measurements from. Some said total length while others said center of ball to center of ball. This is NOT magic. It's a pushrod with cup at one end, ball at the other end, this much longer than stock. How hard can that be ?
Click to expand...


Is this what you want to know?
The length of the hydraulic pushrod for adjustable rockers is ABOUT 7.265 and I say ABOUT because several things affect pushrod length.

The length of the sold lifter pushrod for adjustable rockers is ABOUT 7.531, again about because several things affect pushrod length.

That should get you close if the heads and/or block has had the **** milled out of them, the stem height is correct and we ASSUME a common base circle diameter.

That's as close as you can get. The best way to figure pushrod length is to do a mock assembly and measure for the correct length. The numbers above are "close".
 
I remembered the "go to" application for adjustables with a hydraulic cam was the 340 6 pack engines in the AAR/TA cars. The length should be correct as well as the ball/cup ends. Melling MPR157 7.234" long More Information for MELLING MPR157
 
mderoy340 said:
These have worked for me in the past with hyd lifters and adjustable rockers (Hughes 1.5) xe 268 .500ish lift
Summit Racing® Pushrods SUM-G6420
Click to expand...
COOL !! Thanks !! I take it that the adjustables are oiled through the rocker shafts therefore can use solid pushrods. Please feel free to copy and paste your response to the MULTIPLE threads on this where people have WAY overthunk this modification.
 
Lee Prim said:
COOL !! Thanks !! I take it that the adjustables are oiled through the rocker shafts therefore can use solid pushrods. Please feel free to copy and paste your response to the MULTIPLE threads on this where people have WAY overthunk this modification.
Click to expand...
Read through the customer reviews on those pushrods. A few said they worked perfect for adjustable/hydraulic combo and one said they needed shorter ones. (7.234 stock length for the 340-6)
 
Lee Prim said:
COOL !! Thanks !! I take it that the adjustables are oiled through the rocker shafts therefore can use solid pushrods. Please feel free to copy and paste your response to the MULTIPLE threads on this where people have WAY overthunk this modification.
Click to expand...
Correct, oil thru rocker shaft.
 
toolmanmike said:
I remembered the "go to" application for adjustables with a hydraulic cam was the 340 6 pack engines in the AAR/TA cars. The length should be correct as well as the ball/cup ends. Melling MPR157 7.234" long More Information for MELLING MPR157
Click to expand...
I had read that the stock replacement pushrods for the 340 Six-Pack would work for my application but saw some people argue that it was too simple a solution therefore could not POSSIBLY work.
 
Lee Prim said:
I had read that the stock replacement pushrods for the 340 Six-Pack would work for my application but saw some people argue that it was too simple a solution therefore could not POSSIBLY work.
Click to expand...
Nothing is simple. LOL I see that the stock Mellings are 7 234" long but the Sealed power stockers are 7.572" long. The aftermarket manufacturers can't even decide what is correct. I guess as long as the preload and geometry is correct.
 
just remember the Mopar hyd are different height than the Magnum/ AMC 2011
which I would use even with shaft rockers and use oil through the pushrods
I do not like smoked balls
you can use the 6-pack length then adjust for the different heights of the cup
but go with YR and do it right if all dimensions are not stock
 
I have a post here about this. I used a Lunati hydraulic setup on my 67 LA commando build with stock adjustable rockers. Had smith brothers custom pushrods built to get the geometry correct. I don’t think there is a one length fits all answer for this conversion. However the adjustment for this setup is zero lash + 1/2 turn.
 
Wyrmrider said:
just remember the Mopar hyd are different height than the Magnum/ AMC 2011
which I would use even with shaft rockers and use oil through the pushrods
I do not like smoked balls
you can use the 6-pack length then adjust for the different heights of the cup
but go with YR and do it right if all dimensions are not stock
Click to expand...
Who mentioned the AMC lifters needed in a LA block with Magnum heads? Let's not make this thread any more confusing than it already is.
 
You must log in or register to reply here.
-

Back
Top