big block rocker shaft wear?

big block rocker shaft wear? - 11/29/13 03:21 AM

I have a mild 383 with PRW aluminum rocker arms 1.6 ratio. The cam is a Comp Thumper style hydraulic cam nothing radical. The heads are alum. 440 source. The right side of the engine seemed a bit noisy to me so I pulled the rocker shaft off and noticed the bottoms of the rocker arms were making slight contact with the valve spring retainers.

I have a pic of the wear. They are pretty badly grooved but the rocker bearings seem okay. Oiling does not seem to be a problem. This combo was in the car when I bought it.

I am just not sure if I should buy new shafts and try again with the rockers ground for clearance or just try a different set of rockers and shafts all together?

Attached picture 7939945-DSCN5481.JPG

Posted By: Dodgeguy101

Re: big block rocker shaft wear? - 11/29/13 04:00 AM

Is the left side worn as bad? Are the oil holes drilled in a straight line with bolt holes that hold the shaft to the head?

Off hand I would say the shafts aren't hard enough for the type of rockers that are on them.

Posted By: Cab_Burge

Re: big block rocker shaft wear? - 11/29/13 04:43 PM

Quote:

I have a mild 383 with PRW aluminum rocker arms 1.6 ratio. The cam is a Comp Thumper style hydraulic cam nothing radical. The heads are alum. 440 source. The right side of the engine seemed a bit noisy to me so I pulled the rocker shaft off and noticed the bottoms of the rocker arms were making slight contact with the valve spring retainers.

I have a pic of the wear. They are pretty badly grooved but the rocker bearings seem okay. Oiling does not seem to be a problem. This combo was in the car when I bought it.

I am just not sure if I should buy new shafts and try again with the rockers ground for clearance or just try a different set of rockers and shafts all together?

When in doubt, change them all out

Your rockers rubbing on the retainers had to put unforseen pressures on the rockers and shafts so why take a chance on any of those parts for future failures

Posted By: Challenger 1

Re: big block rocker shaft wear? - 11/29/13 05:00 PM

I'd use 1.5 rockers for one thing and get better ones with new shafts.

Posted By: SCATPACK 1

Re: big block rocker shaft wear? - 11/29/13 05:46 PM

Just curious, What oil were you running with these rocker arms?
Since the PRW Rockers are not rollerized, you need oil that has a really high Zinc content. I had the same problem with a set of the iron Isky rocker arms. Kept galling the rocker shaft up. Finally went to a hardened shaft and changed over to Valvoline racing oil which is the highest Zink content you can get now.
Just a thought, but I would at least change the rocker shafts or you are going to experience the same thing again.
Good Luck

Posted By: Thumperdart

Re: big block rocker shaft wear? - 11/29/13 06:01 PM

My Harland-Sharp shafts looked way worse than that so I flipped em over a few years ago during my freshen up and never looked back but they oil the same either way from what I could tell..........

Posted By: StealthWedge67

Re: big block rocker shaft wear? - 11/29/13 08:54 PM

Am I not thinking straight here? Those shafts look like the oiling holes are in-line with the bolt holes (???). I think the shafts I have worked with have all had the oiling holes straight down when bolted up (not aligned with boltholes). This is why there is a right and wrong way to have them installed.

Posted By: Dodgeguy101

Re: big block rocker shaft wear? - 11/29/13 10:00 PM

Quote:

Am I not thinking straight here? Those shafts look like the oiling holes are in-line with the bolt holes (???). I think the shafts I have worked with have all had the oiling holes straight down when bolted up (not aligned with boltholes). This is why there is a right and wrong way to have them installed.

I asked that question as well. If you look close, it appears there is a wear mark where the bolts go down thru down as well.

If those rockers he is using don't have bearings on them, then they aren't round because I would think there would be a wear pattern all the way across, not were it appears the bearings are riding, so I think the shafts aren't hard enough for those type of rockers.

But, never got an answer if both sides are the same or just the one side.

Posted By: idriveagremlin

Re: big block rocker shaft wear? - 11/30/13 05:09 AM

I have not taken the left side rockers off yet to check the other shaft.

What you are looking at is the bottom side that is bolted to the head.

I am using valvoline VR-1 racing oil. straight 40 weight. The rockers do have roller (needle) bearings in them. I do not know what oil was used before i got the car but the engine was assembled and used less than 500 miles before I got the car. probably has less than 2500 miles total now.

I changed the oil when I got the car and then after much prep of the chassis and suspension I went on drag week.

I have a new set of comp cams stainless roller rockers that are 1.5 ratio I guess I will put them on and check them soon after the install.

The car is a 1966 Belvedere 1 with a 4 speed.

Attached picture 7941074-DSCN5478.JPG

Posted By: Blues_Cuda

Re: big block rocker shaft wear? - 11/30/13 01:59 PM

Your car? This is @ Gateway Motorsports Park during Drag Week.

Attached picture 7941205-DSC08191-1.jpg

Posted By: MR_P_BODY

Re: big block rocker shaft wear? - 11/30/13 02:08 PM

Quote:

Your car? This is @ Gateway Motorsports Park during Drag Week.

That 52 Ford PU is my buddies that I rode with during
DW... nice ride.. it runs 11.50 on motor(no roll bar)

Posted By: Jerry

Re: big block rocker shaft wear? - 11/30/13 03:24 PM

the bearings are harder than your rocker shafts. ofcourse the shafts are going to wear. probably a bad heat treat on the rocker shaft. if the bearings are ok on the rockers, which they probably are. I would replace the shafts and move on.

Posted By: Dean_Kuzluzski

Re: big block rocker shaft wear? - 11/30/13 07:03 PM

Quote:

the bearings are harder than your rocker shafts. ofcourse the shafts are going to wear. probably a bad heat treat on the rocker shaft. if the bearings are ok on the rockers, which they probably are. I would replace the shafts and move on.

I agree, not challenging.....any time you have a "focused" load, like small roller bearings with high valvespring pressure, the oiling requirments are of a thicker viscosity than a bushing that basically broadcasts its load but may have more drag. Good quality rocker shafts are what you need.