Problems with Comp Pro Magnum Rockers?

Posted By: A70Runner

Problems with Comp Pro Magnum Rockers? - 04/12/12 03:04 PM

I finally got my 496 onto the dyno. Break in went great! sounded good no leaks(other than junk valve covers) all ok...Go to do first pull on engine. Its making good power for a first pull and all of a sudden we hear a noise and power dropped off. Pulled the valve covers off and found 3 rockers seized to the shaft. Also bent three valves. Great....

I am now hearing that Comp changed the design of these rockers? I bought these in 2006. Is there a better rocker to use? The car has a solid roller in it. Going to be a street/strip car.

Thanks in Advance,

I'm going to call comp and see what they say...

Attached picture 7161768-rocker.jpg

Posted By: JohnRR

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:08 PM

What spring pressures are you running ?

Posted By: A70Runner

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:16 PM

275 seat 650 open

Posted By: MR_P_BODY

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:22 PM

Those must have been snug on the shaft to seize on
the first pull... TD rockers are much better BUT they
do cost more.... sorry you broke it

Posted By: DJVCuda

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:26 PM

The new ones ( unsure when they changed ) are bushed.

Posted By: Mr.Yuck

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:37 PM

I'm guessing you made super sure that they were all lined up nicely w/ the tops of the valves?

Posted By: afxcoronet

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:42 PM

I did that twice on my car with the same rockers, switched to harland sharps and haven't had an issue since...
Curtis

Posted By: JohnRR

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:45 PM

Quote:

275 seat 650 open

That MAY be your problem, I think those ROCKERS are only good for 500 open.

Sharps or T+D's ... $$$$

edit ... Did you make and mods to your oiling to the top end that may be restricting oil ?

Shafts on the right way and are they banana groove ?

Posted By: Moparnut426

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 03:54 PM

Quote:

Quote:

275 seat 650 open

There is your problem, I think those ROCKERS are only good for 500 open.

Sharps or T+D's ... $$$$

Fixed it for ya John

Posted By: JohnRR

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 04:05 PM

thanks , I have roller lifters on the brain

Posted By: Moparnut426

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 04:09 PM

FWIW, I think these rockers with the bushing are far better than the ones that failed in the this thread. Im sure the open PSI is able to be raised a bit.

Posted By: an8sec70cuda

Re: Problems with Comp Pro Magnum Rockers? - 04/12/12 04:09 PM

Quote:

Quote:

275 seat 650 open

There is your problem, I think those ROCKERS are only good for 500 open.

Sharps or T+D's ... $$$$

Harland Sharps on my solid roller 440 w/ Indy heads...very happy w/ them. They were new in 1989, lol.

Posted By: Moparmal

Re: Problems with Comp Pro Magnum Rockers? - 04/14/12 09:55 AM

AFAIK the non-bushed earlier Comp Magnum rockers must be run on banana grooved iron shafts.

Posted By: Big Squeeze

Re: Problems with Comp Pro Magnum Rockers? - 04/14/12 02:02 PM

Quote:

I did that twice on my car with the same rockers, switched to harland sharps and haven't had an issue since...
Curtis

X2......been there, done that.......

Posted By: BSB67

Re: Problems with Comp Pro Magnum Rockers? - 04/14/12 02:40 PM

To determine root cause, other things need to be looked at like how the rockers are being oiled, side clearence.... That said, you were probably beyond the intended limit for the un-bushed version. At one time, I believe that CC qualified the unbushed rocker at 400# open.

Posted By: Roadrunner451

Re: Problems with Comp Pro Magnum Rockers? - 04/14/12 10:36 PM

I have used those same rockers (the unbushed comps) at 580 open seat pressure with zero problems. It's a solid roller .648 lift and 262@.050. I drive the heck out of it, and beat on it at the strip as well. The shafts are just whatever came with the rockers. I have never checked the side clearance, but there is not very much at all since I use the Hughes shaft hold downs. If I remember right, I had to mill a little off the sides of thos hold downs to get them to work.

Posted By: JohnRR

Re: Problems with Comp Pro Magnum Rockers? - 04/15/12 02:30 PM

Quote:

I have used those same rockers (the unbushed comps) at 580 open seat pressure with zero problems. It's a solid roller .648 lift and [Email]262@.050.[/Email] I drive the heck out of it, and beat on it at the strip as well. The shafts are just whatever came with the rockers. I have never checked the side clearance, but there is not very much at all since I use the Hughes shaft hold downs. If I remember right, I had to mill a little off the sides of thos hold downs to get them to work.

For every 5 people that have a problem there will be one that doesn't no matter what the item. Glad they are working well for you. Did you modify the oiling to them, maybe go to full time ?

A70 this guy brings up a good point , what hold downs were you using and was it held down with bolts or studs ? I was talking to Dan/Performance Only about this yesterday ...

Posted By: 64Post

Re: Problems with Comp Pro Magnum Rockers? - 04/15/12 05:16 PM

Quote:

To determine root cause, other things need to be looked at like how the rockers are being oiled, side clearence.... That said, you were probably beyond the intended limit for the un-bushed version. At one time, I believe that CC qualified the unbushed rocker at 400# open.

Agree. Unbushed PMs at 650# open, it was just a matter of time.

I run them with 350# open and RAS hold downs.

Posted By: A70Runner

Re: Problems with Comp Pro Magnum Rockers? - 04/16/12 01:51 PM

Side clearance was good. I was running the comp hold downs with arp studs. I am just going with I should not have been running the unbushed ones.

Anyway I think I am going to switch to the Harlond Sharps. On the summit site it says you may have to restrict the oil flow to keep the oil pressure up. Did anyone have to do this? Thanks!

Posted By: Moparnut426

Re: Problems with Comp Pro Magnum Rockers? - 04/16/12 04:02 PM

Well I didnt on my small block, but I was VERY specific on keeping the side clearance set to the spec. That was oil dosnt bleed between the rockers.

May be different on big blocks though.

Kasey