Breaking Roller Rockers!
 

So I'm having some issues with breaking rocker arms for some reason. I have a simple setup 502-AFR heads-Crane 741 cam- Comp Pro magnum roller rockers- Morel lifters.
What I did was copy the engine I built last year for my Velocity and put the pair of them in my 33 Powerplay. The new engine is the one that's giving me crap. So far I have broken 2 rocker arms. 1 was the first trip out (#7 intake) the 2nd was the this weekend (#8 exhaust). The bottom half of the rocker is breaking off.

I'm loosing faith quickly in the Comp Pro Magnums. Anyone else have any problems with these? I'm thinking I got a bad batch or something. My vavle geometry is perfect.

Thanks,
Frank

Here are some pics of the carnage.

I'm going to order a new set today. I no longer trust these. But I'm not sure what to get now. I thought these were supposed to be pretty tough.

What pushrod guide plates do you have? The guideplates need to be AFR or modified stock to make the U slot longer due to the intake valve geometry on the AFRs or the pushrod will hit the back side of the guide plate. Mine broke the guideplate so it is unlikely that the rocker arm would break but.....

I use Crane Golds no issues for 3 years with AFR 305's. One set is wide body stock from Merc and the other set is the "regular" Crane golds.

Have you been working with RMBuilder?

My guideplates are the ones that came from AFR. I didn't notice any scaring on my pushrod when I removed it either.
I haven't talked to Bob recently, but he was a big help with my setup last year.

Thanks for the suggestions!
Frank

Improper pushrod length could be your issue.

The way I set my pushrod lenght was using an adjustable pushrod I put white metal marker compound on the valve and cycled and adjusted the length till I got the smallest wipe on top of the valve. The roller tip ended up pretty much in the center of the valve.

Any chance the valve springs are coil binding?

Wow that rocker saw som heat. Make sure the pushrod is not clogged! Looks like someone was welding on the thing.
For some reason it was not getting any oil.

Sounds like you're at least close enough on length. Coil bing- or right very close to it is the next bess guess. That would cause those stresses and the heat. Oiling issues can also contribute. I was looking at the broken side and completely missed the opposite where it's discolored. Are they all blue under the bearing?

Changing rockers won't do anything but change the color of broken rocker pieces in your collection. Those Comp rockers are about as tough as it gets.

It looks like the color is from the rocker being tilted up against the poly lock and running tilted after the rocker broke. That had to be some hellatious stress on that bearing. Everything was riding on that bearing and the side of the polylock.

Kind of funny how both rockers broke in the excact same manner on the same side of the rocker.

If I was getting coil bind would it be more prominent on my exhaust valves since the exhaust lift is .632. Intake lift is .610.

I did check the pushrod hole for blockage when I took it out to make sure it wasn't bent. Everything was free and clear.

Thanks for the suggestions guys, keep em comin

Frank

my best guess is your springs are not quite strong enough. When you are on the border line sometimes you can get away with it, sometimes you can't. You can build one engine perfectly fine, another will have bind on one or two valves.

The NHRA top fuel guys test hundreds of rocker arms and springs to get the best set they can. Rockers have slightly different heights and springs have slightly different weights even though they are all labeled the same.

Spring info from AFR's site ---1.625 O.D. Roller Dual Valve Spring with dampener,
255 lbs. on seat, .750" maximum lift

Do you know what pressures your springs are set to?

I just ordered some Crane Golds and should have them tomorrow. I'm going to replace them and see what happens.
If it's the motor then they will break too. If they don't then I know I got some bad rockers from Comp.

255#

We use both the Comps and the Cranes here both without any problem.

Have you had them on a scale and measured coil bind height? I've had both the wrong parts and out-of-the box defectives... more than once.

No I haven't, but I will now. Thanks.

Frank

Good idea to check that out.

Frank,

While I haven't recommended or used these rockers, I am familiar with the issues you are experiencing. It is not a setup, stack, or geometry related failure. It is a warranty issue. If you would like some assistance in obtaining a RMA slip to return these items, feel free to call me. Attached photo is of a Ford Pro Magnum rocker with a similar failure pattern.

Regards,

Bob

In late 2007, I had major engine damage due to the total failure of a complete set of solid roller lifters from a major manufacture. We did all the home work/analysis and then got the manufacture to finally admit that they had a problem. They said they would "help" then ignored all our follow-up calls and would not communicate. In the end, they wrote me a check for $18,000+. Unless the manufacture can convince you that they are past the defective rocker issues, I would move on to a proven make/brand endorsed by a pro and not risk a complete engine failure....even if they replaced them for free.
You are really lucky the failed rockers were the extent our your damage.
I would have confidence buying whatever roller rockers Bob recommends.

I ran Crane std body gold rockers for 3 issue free years,switched to comp pro magnums and then had repeated failures of rocker nuts cracking due to improper heat treat (very brittle). The last one wadded up a pushrod and wrecked a pair of lifters and my vacation,switched to arp nuts for the rest of that season with no more failures.Switched to T&D shaft system the next year and have been problem free. I don't run the kind of spring pressures your running but I no longer trust the quality control of comp cams rocker components,I would switch brands if I were you,Smitty

I just had a Comp Hydraulic flat lifter break into pieces on the dyno the second the motor fired. No one I know has ever heard of or seen this. There's always inconsistencies from any company that produces mass quantities but lately I've had problems with pushrods, cams ground wrong, rockers, and my exploded lifter that cost a customer a long weekend and me a lot of money. Is Comp goin down hill?

sorry for the hijack, just needed to vent :mad:

In my eyes Comp has gone down hill with lots of things. Rocker arm breakage, adjuster nut breakage, etc is not uncommon.

Last big thing breaking over there is there beehive springs. Yes, the ones that they heavily advertise as being the best things ever. They originally used springs made by PAC and then switched to crap. You'll see broken beehive problems on most performance sites. The fix is to go back to PAC's. BTW: A single spring set-up that breaks usually causes more engine damage as there is no other spring (like in duals) to help hold valve up when one breaks. DOh !

Back to rocker arms - Comp has been anti-aluminum for ever, until now. Did they give in ? Did they realize many of their steel one's broke ? Or did they really discover a "revolutionary" process ? I know which of those I pick. Doh.

Are you sure ?

On a Hydraulic roller set-up ? I know of going 170lbs-180lbs or a little more seat, but 250 ? What's the psi at your max cam lift ?

.750" max lift means there's some more (over .750") before actual bind and your running around .630" or so ?

Interesting.

I have not run into this failure, I ran a set of these in a jet boat engine with no issues, but like one other post...looks like you have a bad oiling issue, major heat stress looks to me from that coloring. do you have the lifter oil restricted ? have you run it with the valve covers off to see oil flow ? could even have a cam bearing installed wrong..happened to me by a machine shop...Rob

Well if you look at the cam card for the Crane 741 cam you are about 100psi over recommended. I would fix that problem first. Not a Happy valvetrain !

Also you might want to check you lifters at this point. I am surprised they did no explode.

Ok, here's an update. I checked my spring pressures and I'm at 160ish pounds off the seat. That's the best I can tell with the moroso pressure checker that goes over the roller rocker. Sorry I missinformed you guys. I just took the spring pressures off of AFR's site and forgot that I specifed what springs I wanted when I ordered the heads.
I got the new Crane golds and I'm putting them on now. I've talked with a few engine builders today and there seems to be a theme here. These latest Pro Magnums that are off the production line are all having problems! Comp is not admitting it but they are replacing the entire set for me. It's nice to know that I'm not the only one with this problem, but it sucks that I bought what I thought was a quality rocker so I wouldn't have any issues and here I am breaking them left and right!
I'll be sure to report back after I run it with the Crane Golds.

Again sorry for the mis-information about the valve spring pressure. But either way the roller rockers should hold up no matter what springs I'm running.

I don't think I have an oiling issue since there is oil actuall dripping out of the bearings on the rockers right now. The heat from the rocker cam after it broke. You can see the piece that broke off is the original color so that tells me it broke before any heat cam into play. Once the rocker broke it was canted off to the side and rubbing the top and bottom of the polylock which caused the heat that your seeing.

I'll report back tomorrow after I run it with the new rockers.

Thanks for all the help guys,
Frank

Frank,

The AFR Hydraulic Roller spring option sets up initially at 170# seat force and 460# open. If they are checking @ 160# seat after initial run in, given the margin of error on the Moroso checker, you are well within tolerance. We have run a number of AFR packages with the HR spring option and they show only marginal sag after 150+ hours.

To be clear, I do not use nor do I recommend this particular rocker arm, my suggestion regarding the RMA slip was due to the fact that it will be your only recourse available that will provide you with any compensation. I mentioned this as a warranty issue as yours does not appear to be an isolated instance. With a new set of 16 rockers and Polylocks you can place them on racing junk or Ebay an attempt to recover some of your loss.

The root cause of the failure is the stress fracture in the body, while the heat discoloration is a collateral damage as a result of excessive load bias from the trunnion opposite the original failure point.

Prior to installing the Cranes, be sure to examine the studs and guide plates for any damage. A stress riser on a stud may cause a secondary failure.

Bob

This site is invaluable. I have had good luck with those rockers and was about to order six sets. Not now.

As always, Bob is an incredible resource.

LS1Nova-

With the new rockers make sure that you clean out all the grease out of trunnion bearings and roller tip. This grease is for corrosion control and holding bearings during assembly - not too good of a lubricating grease. Then put in a container of oil. Let sit for a while and before installing rotate the trunnions in the oil to make sure bearings are bathed in oil. Some people do this, others don't - those that don't are usually those who did not read the instructions or where not given the instructions to read.

Also check to see if rear valve cover bolt bosses will touch two of the rocker arms. Sometimes this is an issue, sometimes not. If so, a little grinding on rocker will fix it.

Thanks for the heads up SB! I did give them a douching with brake clean then hit them with the air gun and dunked them in oil before they went on.
The new Crane golds have the corners cut off already for the clearance issue you were talking about. Pretty cool.

I just got in from running it on the hose and all is good so far. The only difference I can tell is that the aluminum rockers seem to have a little more of the sewing machine sound compared to the comps.

I'm going to try to take it out tomorrow night and give it a good run. I'll report back with the results.

Frank

Here's a few pix of the new Crane Golds with the corners cut.

This is great!!! I just got back from ripping up and down the river. I ran the boat at 5800 about 6 different times and all is good so far. This is the first time I've been able to get on it without having a broken rocker when I get back to the dock! Actually I ran my best mph with these particular props too. I'll confirm it next time I go out, but I'm confident this issue is resolved.

Again thanks everyone for the input and suggestions!
Frank

Glad to hear it Frank!

Boyahhh ! good deal Frank !

Good deal. Glad it worked out.

Just thought I'd report back. I took the boat out again and put some time on it. No issues to report besides a small oil leak from my dipstick tube at the pan. I'm very happy to have this rocker issue resolved! F---in Comp Pro Magnums!! I'll never make that mistake again!