Lapping Rocker Arms

[PackardV8]

The Stamped style rockers I use on my Vortec 406 are the Crane branded with the roller tip. I had these on my old 350 also.
No idea who manufactured these for Crane.
I'd like to get additional sets of at least equal quality.
No idea if the roller tip on these add any value.
Doesn't seem to slow it down any.

My reservation with those is they are the opposite to what Chev developed for the LS.

X2 - back when they were the new thing, I spoke with an LS engineer and he said roller tip rockers didn't add any power, but added significant failure risk.

[1980RS]

Lapping a rocker arm? begs the question, why? I ran stock rockers on my 406 Vortec headed engine back in 2019. Only thing I did with them was to make the rocker slot longer. Tossed them on and went off to the track. There is a reason I run stock rockers over rollers and roller tip rockers but it's so lame no one would want to hear it anyway, .

[jeff swisher]

Jeff,
Do you mind telling us what brand rockers they are ? When I was doing some dirt track engines years ago and they had to run factory style rockers we always had the best luck with the Crane "Nitro Carb" rockers. They had grooved balls. I would be afraid of the ungrooved balls getting oil starved with any higher than stock spring pressures ?

I have a set of Comp big block ones on the shelf. I might try some Prussian blue and see how they look. Not sure if i would want to lap them or not.

These are made for summit racing for them to sell as their made in USA brand Elgin rockers is what these are.

I stuck one on my 57 chevy and poured some Driven BR oil onto the rocker and ball and it seeped out the stud hole but not as fast as I thought it would but it was cold like 50 degrees.
Took the car for a drive 11 miles to the cam shop and hung out for an hour and went back home 3000 rpm cruise there.
Hit 5700 rpm back and cruised at 4000 rpm back.

Got the valve cover off as quick as I could 2 minutes maybe and checked temps and all rockers and springs were between 186 and 191 F.

Pulled the rocker off and looked for wear marks.
Very thin witness mark.
Picture. Look at the ball and you can see a thin shiny area where it contacted the rocker . North side of the ball.

[1980RS]

Looks more like poor quality parts to me. I have plenty of GM rocker arms that have a nice pattern on them where the ball meets the rocker, but if it's an interference fit there going to be heat with 2 parts rubbing against each other. That's why the grooved ball is so important, to get more oil in there.

[pamotorman]

GM uses kool nmuts on its circle track crate engines with stamped rockers to prevent the oil from overshooting the ball.

[1980RS]

GM uses kool nmuts on its circle track crate engines with stamped rockers to prevent the oil from overshooting the ball.

Al we used were tall stud locks off old roller rockers, did the same thing as you describe. I also know there is some sort of deflector plate that goes on top of the rockers to keep the oil on them also. I used to use oil restrictors on my drag race stuff but stopped after we found out that the springs got hotter, we then stopped using the restrictors.

[smclendon]

You should also check where the push rod end and rocker arm cup are. There are times the radius is not the same.

[jeff swisher]

I stuck these on the shelf and got some full roller rockers chrome molly steel ones.
I have ran these full rollers before but 7/16 stud and will give these 3/8" stud ones a try.