OEM magnum lifters setup

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DartFred

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Is it normal for the stock OEM magnum lifters to bleed down at rest? I did not start the engine yet, just primed it with a drill. It takes up the lash with oil pressure but after 2 minutes the stock pedestal rockers are loose. I checked no.1 intake valve it takes almost half a turn to get the pushrod to stop turning. I had to go fast before the lifter bleeds down. I guess I need an assistant to prime the oil with I check all lifter preload....

engine is a 360 magnum, RHS magnum heads with stock rockers, pushrods and lifters.
 
I don't know if its normal or not, but mine does the same thing.

Supposedly some of the lifter bores in these blocks are machined poorly at the top. You might check that out while you've got it apart.

Also, these lifters seem to take an awful lot of preload.
 
LXguy said:
I don't know if its normal or not, but mine does the same thing.

Supposedly some of the lifter bores in these blocks are machined poorly at the top. You might check that out while you've got it apart.

Also, these lifters seem to take an awful lot of preload.
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Are you running your engine with the lifters bleeding down? Mine seem to pump up pretty quick as soon as I prime it with the drill. I wonder how it will react on startup....
 
Hey

After responding to this thread I happened to have mine apart this weekend and I gave it a closer look.

I think it might be a symptom of the pushrods being too short, like its not compressing the plunger past the weep hole or something, so the lifter bleeds down and then there's a little slop in the valvetrain.

To test this theory I installed some comp cams 6828 pushrods (they are .33 longer than stock. Lo and behold my car doesn't seem to bleed down so quickly and it is quieter.

Obviously I am going to check into getting some longer ones still, but thought I would spread the word. Checking pushrod length with pedestal rockers sucks, btw.
 
DartFred said:
I checked no.1 intake valve it takes almost half a turn to get the pushrod to stop turning.
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What do you mean here? Half a turn on what?

The stock rockers should be tightened down all the way, all the time. torque to 21 ft lbs and done.
 
LXguy said:
Hey

After responding to this thread I happened to have mine apart this weekend and I gave it a closer look.

I think it might be a symptom of the pushrods being too short, like its not compressing the plunger past the weep hole or something, so the lifter bleeds down and then there's a little slop in the valvetrain.

To test this theory I installed some comp cams 6828 pushrods (they are .33 longer than stock. Lo and behold my car doesn't seem to bleed down so quickly and it is quieter.

Obviously I am going to check into getting some longer ones still, but thought I would spread the word. Checking pushrod length with pedestal rockers sucks, btw.
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Did you mean 0.033'' longer? .33'' is a lot
 
LXguy said:
What do you mean here? Half a turn on what?

The stock rockers should be tightened down all the way, all the time. torque to 21 ft lbs and done.
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Yes I know pedestal type rockers should be tightened all the way down, but I backed it up to loosen the pushrod, tightened it to 21 ft lbs and it took about half a turn when I got it torqued and pushrod stopped turning at the same time. I think the stock pushrod must be a bit too short, maybe around 0.030'' like you found
 
You also want to make sure the little hole in the lifter points up (towards the valley) as they can be installed 180° out and that may cause lifter filling issues and noise.
 
Sorry, .033 longer, not .33

I bet .050 would be better, but the 6.933 were only $23.00. When I get it dialed, I'll get some real pushrods. But for now the difference is night and day.

Measuring pushrod length with pedestal rockers sucks for sure. I made some solid lifters which helps (only tighten to zero lash), but still very subtle differences.
 
moper said:
You also want to make sure the little hole in the lifter points up (towards the valley) as they can be installed 180° out and that may cause lifter filling issues and noise.
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Whaaa? The lifters spin in their bores due to the crown on the cam lobe....
 
pishta said:
Whaaa? The lifters spin in their bores due to the crown on the cam lobe....
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Not on a Magnum engine. They use hydraulic rollers. The factory ones have a paint mark on them to note which "side is up". Aftermarket ones, or most used ones there is no outward mark except for the hole itself.

If the cam and lifters were changed and replaced with a flat tappet I apologize - that wasnt how I read it.
 
Yeah, you get hydraulic rollers spinning in their bores and you're going to be hating life with a quickness...

Mine is hydraulic roller btw.

Mine pumped up when I would run the oil pump up, but still were noisier at idle than I liked. Should have done the solid lifter check from the get go...
 
Brought back from the dead and I think you just did me a favor. My lifters also bleed down and the valvetrain is quite noisy in my magnum. If I'm reading this thread correctly, going to a slightly longer pushrod could solve both these issues? If so I'm sorry I missed this thread last year. It would be pretty inexpensive to give it a shot, is ~.033" longer still the way to go? Like this?

http://www.summitracing.com/parts/lun-80762-16/overview/
 
You do also know that the OE hydraulic rollers only install one way too, right? That's with the hole in the lifter facing the intake valley. If they are installed the other way, they can bleed the oil out from gravity and be noisy on startup.
 
I just wanted to follow up on this. I bought a set of the pushrods I linked (6.936") and there is a noticeable improvement over the stockers. The lifters seem to hold their prime better so it doesn't "rattle" as much on a cold start, it sounds almost stock at idle, and the "sewing machine" sound is reduced at rpm. You can still hear it so maybe a longer would be better, but this length makes a difference.
 
That aftermarket cam,probably ground on a smaller base circle. How they get the lift up. Jesus,that car is quick.
 
Abodybomber said:
That aftermarket cam,probably ground on a smaller base circle. How they get the lift up. Jesus,that car is quick.
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Needs to be quicker, lol. Problem is that I REALLY love how streetable it is. I drive it everywhere. As a matter of fact I took a 700 mile trip to my dad's over the 4th. I even took it to the track the night before driving back home, the car's reliable as a rock. But, it's to the point where it needs it's safety equipment updated to run to 10.00 and to me that's when it really starts to be a race car.
 
UOP,have been there. I like the traditional street/strip machine,over a car with safety/e.t. modifications.That NHRA 11.50 no bar helps.
 
LXguy said:
Sorry, .033 longer, not .33

I bet .050 would be better, but the 6.933 were only $23.00. When I get it dialed, I'll get some real pushrods. But for now the difference is night and day.

Measuring pushrod length with pedestal rockers sucks for sure. I made some solid lifters which helps (only tighten to zero lash), but still very subtle differences.
Click to expand...

Where did you find the pushrods for that price?
 
Nevermind just saw summit link. I'm getting ready to prime my la roller but I've got adjustable rockers.whats the best way to preliminarily adjust them? Like a Chevy? Tighten until you can't spin pushrod then 1/4 turn? It's been a long time since I've had to adjust valve train.
 
La uses a different push rod ,not useable with a LA/Magnum hybrid,or all LA. On my Magnum converted to a Chev rocker stud, same adjustment as a Chevy. Gotta get the push rod length right first.
 
I don't think the pushrods I linked will work for you. They're for a stock Magnum with stock rockers.
 
Don't magnums run through pushrod oiling as well? I've got to get ball and cup oil through pushrods for my la roller. Where's the best place to get them and what's the best way to get a proper length of pushrod so I can order some? I did it 15 years ago but I don't remember. Thanks guys
 
Order the Comp Cams adjustable push rod., Tape measure the rough length, order the matching length Comp Cams push rod. Marked with an index,every index match (1turn),= .050". Like adjustment, on a Chevy ,look for zero clearance(push rod resistance,to turning with thumb and forefinger.). Resistance increases,add .030"-.060".
 
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