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Poking holes in my rockers

Frank Mopar

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I have drag only 440. Same set up since 2015. Comp cam 507/510 lift, hydraulic rocker, 440 Source heads. Stamped stock rockers.

Now the thing is poking the pushrods through the stock rockers. Different cylinders, intake, exhaust doesn't matter. Even bent pushrods. Not being over reved.

Shifting @ 5400. Traps out 56-5700. High 7.20’s 93+mph.

Any thoughts??
 
Hmmmm...just thinking out loud. It sure sounds like "something" changed, but my first guess would be the stock rockers just wore out/failed and the pushrods bent as they jumped out of the "cups" in the rockers. Otherwise it doesn't make sense. If nothing else changed (head gaskets the same, head/block surfaces not re-milled, etc.) and assuming you had pretty close to the correct pre-load on the valvetrain.....the valvetrain can only get looser from wear, not tighter.
 
Pretty common. The ball area gets a wider swipe with the larger cam. Then it pops the cup out. Mopar Performance used to make thicker rockers. Put a new one and run it.
Doug
 
Pretty common. The ball area gets a wider swipe with the larger cam. Then it pops the cup out. Mopar Performance used to make thicker rockers. Put a new one and run it.
Doug

Unfortunately the MP rockers are no longer available so I replaced all the rockers with a stamped set from Mancini. Same thing happened. Twice.

I now have a set of Comp Cam adjustable pro magnums (i measured and ordered correct length pushrods) and last night one of the pushrods fell out of the cup.

Do you think the valve springs on the 440 source heads are getting weak?
 
did anyone check out the heads when you got them or did you run them out of the box? springs and valve guide clearance needs to be checked, I've found lots of tight guides on those heads.
 
I had the same probl;em years ago with the Mopar 484 Purple shaft cam
First time it happened I figured out I missed a wore out rocker so I checked every one left
The second time it happened I said never again
I replaced all of my rockers with the Crane ductile iron rockers
 
did anyone check out the heads when you got them or did you run them out of the box? springs and valve guide clearance needs to be checked, I've found lots of tight guides on those heads.

Heads have bern on since 2015. They were at a machine shop in the spring for leak test

I called Comp Cams and after I said 440 Sourxe he said springs right away. Lol
 
Something is causing lost motion if the pushrod fell out. Weak spring, guide bind (tight, bent valve). I'd start with popping the spring off from the valve that lost the pushrod. Grab the valve after the spring is off. Remove the air from the cylinder and see if it moves up and down smoothly. Have the spring pressure checked at the same time.
Doug
 
It’s actually not that uncommon with a hyd cam and either the Comp or PRW rockers for the pushrods to fall out.

The situations I’m familiar with happen on start-up, not while it’s running or being revved.
The root cause is a lifter bleeding down after the motor is shut off and the plunger is at the bottom of the lifter, combined with pushrod cups in the rockers that aren’t very deep.

After the motor is shut off the lifter bleeds down on a valve that is on the closing side of the cam and the plunger gets bottomed, and then you have the valve resting on the seat after the lifter is bled down.
When the motor is cranked over on the restart and that lifter goes back down in the bore, but the rocker isn’t trying to follow it because the valve is already closed, and the pushrod falls out.

I know of this happening with both hyd flat and roller cams.
Never with any solid lifter cam.

It seems to happen more when the lifters have very light preload in them.

I haven’t tried it, but I suspect running more preload would help.

We had a 440 here with PRW rockers that this happened to numerous times.
Different pushrods each time.
This was my first experience with it.
We switched to the Mancini HS rockers and cup style pushrods.
The cup in the pushrods was noticeably deeper than the cup in the PRW rockers, so I figured it would be harder for the pushrods to fall out.
We also went with a little more preload.
Never bothered again.
With the PRW rockers, a couple of times the pushrod didn’t fall all the way out, it just slipped out of the cup and the pushrod was wedged into the corner between the cup and the body.

After we experienced it here, I talked with several others who had similar stories. Most of them solved it with solid lifters.

Like I said, this is referring to instances when the pushrod falls out during start up........not any other situation.

As for the Stealth springs giving up...... I have no idea how well they hold up, but that’s a pretty low cost item to replace for some piece of mind.

As a side note.....The XE series of cams just aren’t that well suited towards higher rpm use.
At 5700 there is already likely some unhappiness, and the pushrods going through the rockers is the tell tale that things are not running super smooth.

Running a hyd cam in a “race car” is false economy imo.
You get less performance, and when used with stock replacement type parts the reliability isn’t always great.

Run a solid cam along with some sort of aftermarket rockers right from the start.
More power, more reliability.

Or, if it has to be a hyd, use something with smoother lobes.
 
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you better check out the springs. I had just the opposite happen. mine bore a hole in the lifter cup. found that spring was way weaker than all the others and firmly believe that was the cause. i put all new springs on and put many more passes on the engine.
 
Inadequate valve springs do all sorts of damage. Proper pushrod length is also really important. Hydraulic cams have several variables, as other posts have pointed out. I never ran a hydraulic in my drag motors, couple of solids, mushrooms & several solid rollers. All used aftermarket rocker arms, Isky & Crane Gold offset for my ported heads. Good rockers & proper pushrods with correct modern valve springs for the cam.
 
All of a sudden this problem started Always at high rpm never start up. Always a Different cylinder. If it was the sane cylinder I could look at other things. Already cost me on a bye run to the finals. Man that sucked!

I thought cups on the Comp Cam Pro magnums look shallow but wtf, married to them now. You thing you buy the good stuff and your happy. NOT! This will be $1,000 mistake

Thanks for the help guys. Im going to replace the springs and check the guides. I don't know, maybe I take the cam/solid lifter advice.
 
IMHO guide clearance always needs to be checked, all builders I have talked to has found less than ideal clearance in all the aftermarket brands. Valve springs seem much better today than "back in the day". But my cams where much larger than yours & in my stupidity I ran much higher RPM.
 
I had a pushrod fall out and sit on the edge of the cup, didn't notice it until it wore a grove in the pushrod and started kicking up noise. xe275hl cam, johnson hylift lifters and 1.5 PRW's in stainlesss. I would think the problem happened from bleed down as the car sat for a few months while I had the trans out.
 
I thought cups on the Comp Cam Pro magnums look shallow but wtf, married to them now. You thing you buy the good stuff and your happy. NOT! This will be $1,000 mistake

Why would you be upset. Neither the rocker nor the cup is the problem. Fix the problem, likely either junk lifters or valve springs. Or simply adjust your lifter 0.010" to .020" off the bottom. You'll probably pick up power.
 
Why would you be upset. Neither the rocker nor the cup is the problem. Fix the problem, likely either junk lifters or valve springs. Or simply adjust your lifter 0.010" to .020" off the bottom. You'll probably pick up power.

I agree. Hope the springs take care of it. If it was one cylinder I would think lifter but its not.

I still would like to see a deeper cup on the rocker but iiwii
 
All of a sudden this problem started Always at high rpm never start up. Always a Different cylinder.

The pushrods going through the rockers is usually a high rpm thing.
But if you’re having pushrods falling out at rpm with the new rockers, you’re into some serious float would be my guess.
The new rockers are likely heavier than the stamped ones, which would mean the loss of control will happen at a lower rpm...... and to a higher degree.

Be a good time to upgrade to 10deg retainers and locks while you’re at it.

The ones where I’ve had conversations about pushrods falling out from the PRW and Comp rockers have all been during start up, like the motor we had here.

When you swap out the springs, it would be interesting to know what the pressures are on the used springs(if you have a way to get them tested), compared to what they are when new...... to see how much they lost.
 
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The pushrods going through the rockers is usually a high rpm thing.
But if you’re having pushrods falling out at rpm with the new rockers, you’re into some serious float would be my guess.
The new rockers are likely heavier than the stamped ones, which would mean the loss of control will happen at a lower rpm...... and to a higher degree.

Be a good time to upgrade to 10deg retainers and locks while you’re at it.

The ones where I’ve had conversations about pushrods falling out from the PRW and Comp rockers have all been during start up, like the motor we had here.

When you swap out the springs, it would be interesting to know what the pressures are on the used springs(if you have a way to get them tested), compared to what they are when new...... to see how much they lost.

Already have the 10 degree retainers so we’re good there.
 
Any idea 'who' makes those stamped rockers for Mancini?


I was told Elgin Industries from others but can’t confirm so so don’t shoot

Honestly I returned mine before I even installed them

Man they measured thin and looked bad, read some reviews on Mopar forums confirmed


Anyways


Went with Sealed Power instead , rockers and shafts was impressed with measured thickness versus the factory Mopar rockers

Couple summers now

So far so good running the Comp Cams XE 275 HL and lifter set

Edelbrock E Street 75cc

Shift at 5400/5500

Mostly street car
 
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