FYI Comp Cams Magnum roller rockers

[dantrap]

I found out the hard way that the Comp Cams Magnum roller rockers do not like high RPM's in a roller cam application. They have tight .0015-.002 I.D. clearance and no bronze bushings for the Shaft, this combined with roller springs over 350# open and the gall up on the shafts. So now i am having them bored and bushed. After i hosed up my engine I found a whole bunch of info on this problem on the Big block dart web site, I guess its common. I had these rockers left over from an old .590 solid motor and figure i would run-um. What a mistake. Funny the old factory solid lifter rocker were not bushed and we run them on roller motors in the past no problem. But i believe they have like 5-6 thou of clearance. Can someone with a set let me know the i.d. . Thanks.

 

[dantrap]

Just to clarify, it was my problem not the rockers. Wrong application, they work fine on a flat tapper engine with out big spring pressure.

 

[daredevil]

were these the pro magnums? im using a set on a 575 lift solid roller and now im worried. i saw a toasted set on a sb but it was a hardness issue. was yours a la or rb

 

[rumblefish360]

No, regular Magnum's. There a very good roller for street or light strip applications but do have a limit as read above.

The "Pro Magnum" rocker is a race designed rocker IIRC.

 

[Meep-Meep]

I believe the issue is the material. The OEM rockers are iron against a steel shaft and I believe the Comps are steel. Also the tighter the clearance the more surface area available to carry the load and to keep from breaking through the oil film. You should just need enough clearance to get oil in. I have factory ones and a set of old Cranes that have galling and that seems to be the norm. I will take a closer look but I may end up bushing them.

Here's something else to consider. I was making some art projects using Ford small block rocker arms and the pivot balls and when I tried to weld to the pivot ball a bunch of crap boiled out of it and got all over my tungsten. Upon closer inspection the pivot ball has a grainy appearance because it is an oil impregnated sintered material. Now, those things run in an engine for 150K miles and I have never seen one galled. I think making a sleeve bearing to float in the rocker out of that stuff may be the answer.

 

[dantrap]

They are the std magnums. i believe they will work great with the bushings and some clearance. Dorvak Maching makes a bushing set with smaller dia. shafts, but i am going to use standard industrial bushings. We use them on hi-speed machines all the time.