Pushrod Through Rocker Arm

[sportster2000]

What I am about to tell you all is second hand info about my car. Quick explanation is that my car live 120 miles away from me in my brothers garage. As payment he gets to drive it when ever he wants to. He sent me pictures which I will post below. The valve cover gasket was leaking so he got new ones to replace them and when he took the valve cover off he found that not one but two push rods were poking through the rocker arms. These rocker arms were from the original 1968 dated heads that were used. The cam is a Comp Cams 509 lift.

Xtreme Energy 240/246 Hydraulic Flat Cam for Chrysler 383-440

Xtreme Energy 240/246 Hydraulic Flat Tappet Cam for Chrysler 383-440 (Single-Bolt) street/strip applications. Needs 2800+ stall, 9:1 Compression. Rough idle.

www.compcams.com

The valve springs were upgraded from factory to a heavier spring pressure as part of a kit from Mancinni Racing. I do not know the compression pressure rate for these springs. Couple of questions,

Are roller rockers worth it?
Is this just a fluke from older parts failing or should I be looking at some other items first?
Is the best option for the cost just to replace them with stamped steel one?

 

[70chall440]

Given that the rockers are factory and you changed the cam and lifters, it might be time for at least new rockers, doesn't have to be adjustable but might be an upgrade.

 

[MerlinsMopars]

With that cam, It was an issue with clearance and non adjustable rockers for me also. The preload on the lifters were maxed out and we had to measure for new ones. When we went to fire it after the cam install, it bent several of them. I always got. the adjustable ones ever since. I like comp cams version but then you still have to get the right pushrods. 1.5 will give you a little more lift but be careful with stem clearance.
Cheapest way would be to get new rockers and measure for the correct pushrods.

 

[NoCar340]

It's entirely possible they're just old parts failing. The higher-pressure springs obviously didn't help the situation, especially with solid-end pushrods. Replace all 16 pushrods and rockers. Do not attempt a "limp home" repair of just the damaged parts; this will happen again.

What work has been done to the heads? Were they milled? Was any guide clearancing done for higher valve lift?

First and foremost: If you changed the cam and lifters, you probably now have "AMC" lifters, which means they have oiling orifices in the pushrod cups. AMC and Mopar lifters were identical in every way except that detail, because AMCs oil through the pushrods. The AMC style have been the only thing in the aftermarket since about the mid-1980s. Once you've got the rocker shafts off and the pushrods out, peer down there and see if there's a little hole in the middle of the lifter. If so, make sure your new pushrods have oiling holes on both ends. The pushrod cups in your new rockers will thank you.

I always measure for pushrod length rather than go with what a catalog says. I don't know what Joe Bob did to my heads before I got them. About 90% of the time, a little catalog foraging will net a "pushrods by length" section that shows something very close to what you need without having to pop for custom pushrods. In the case of my 440, I had the heads milled .070" (at least, that's what they told me) so I would expect my pushrods length to be factory minus .070" as a starting point. I will take actual measurements, though, and order from there. Length checking is much easier with adjustable arms, but not impossible without. Your optimal pushrod length would preload the lifters between .020"-.030" with the cam on its base circle. I like to aim for the low side of that, but it's not of great concern on a driver. .050" is excessive enough to affect performance and wear. With stamped arms, you won't get a consistent reading on every lifter, so don't panic. The real value in adjustable arms is the ability to precisely set preload on every single lifter, not some gee-whiz roller tip.

I'm not a huge fan of roller rockers for street engines, at least not aluminum ones. They just don't seem to hold adjustment very well, particularly on hydraulic cams. Ductile-iron arms hold lash/preload much better in my experience, and that's what I use on most builds (I haven't used stamped arms in decades). They were used by the factory during the solid-cam era (early B/RB) and both DC/MP and Crane offered them in the aftermarket in 1.5 and 1.6:1 ratios. You'll want to stay away from the 1.6 arms unless you're able to verify your guide-to-lock clearance, which I expect may be cozy if unmodified. The Mopar rockers are long gone and the Crane ones are a bit pricey (when they're available) but used sets can be found in the $200-$300 range. As far as roller rockers being "worth it" from a performace standpoint, don't waste your money. As I was once told by a multiple-national-record holder, "You'll never find it on the dyno." Good ductile arms for $300 are a better long-term investiment. Set it and forget it.

 

[moparleo]

Tear down time. No assumptions unless you like drama. Probably have lobe damage on the cam, metal in the pan. And what else. A picture just tells you what happened. But it doesn't always tell you how/why. And that is the most important question to answer so it doesn't happen again.
Many things can cause it. Don't just guess and replace a few parts. Even more major damage could be down the road.

 

[sportster2000]

I figured it was going to be done level of tear down going into this. It’s going to be new lifter, measured pushrods, and rocker arms going in it. I already planned looking at the cam to see if there was any issue with wear on it. Thanks for the answers to this.

 

[gzig5]

The stock rockers have a limit for lift and spring pressue they can handle. This failure mode is not unheard of on the stamped rockers. Mopar Performance made a heavy duty version of the stamped rocker but I don't think it is available any more. Best bet is a set of aftermarket bushed bore, roller tip rockers like the PRW, Comp Pro, Hughes, Harland Sharp, etc. Needle bearings on the pivot are not a good idea with stock rocker shafts IMO. Motor should come apart to get the bits cleaned out and probably need new push rods.

 

[sportster2000]

My brother was able to find the missing rocker arm pieces. They were fatigued. One had a crack on the top side of the piece that did not go through the dome. He was able to get the lifter out that came apart. All parts were laying right there. I am still going to look in the oil pan and take the filter off to cut it open to take a closer look for smaller debris. This Friday will be inspection day. Taking the day off to travel and work on the car.

 

[Rons340]

A couple things to check, especially since you have upgraded so many parts. First is the overall geometry of the valve train. Coil bind is the leading culprit for rocker arm failure along with excessive open valve spring rate pressure. I have also seen the rocker arm foul off on the spring retainer at full lift due to high valve lift and incorrect rocker arm positioning.
I would start from scratch and measure everything carefully to be sure all of your parts are operating happily together and are compatible together. If you are going to remove the motor, a dial indicator and degree wheel would be the best to dial it in, if you are going to attempt an in-car repair visually inspect all of your pivot points closely. Be sure that the rocker is contraction the valve steam squarely and in the center.
You should be able to use the stamped rockers with no issues but if you don't correct the cause, it will happen again, even with new parts.

 

[Chryco Psycho]

Roller rockers will reduce valve guide wear as they don't push the valve away from the rocker shaft as the valve is lifted , but I never use alum on the street , the Stainless rockers are good , I use a lot of the PRW ones as they are reasonable price .
I also use a lot of Smith bros pushrods , they are out of Bend Or. & can ship a custom set in 24 hrs , great service & price .
Make sure you use lash caps on the top of the valve but the locks may need to be replaced to allow the lash caps to fit correctly .
Cam profile is not my favorite , not much lift & too much duration needing 2800 rpm stalll , might want to look at a far better cam grind .

 

[70Hardtop]

It's entirely possible they're just old parts failing. The higher-pressure springs [.main body...] Good ductile arms for $300 are a better long-term investiment. Set it and forget it.

This was an excellent post! Lots of good info. I didn't know. Thanks