Side Clearances on Comp Pro Mag Rockers

[Mike67]

So I have a dumb question, when setting up my clearances Comp says that I need .030, is that for each set of rockers between pedestals (total), not on each side of the rocker? (.060 between stands)?
These have Comps steel hold downs and the solid steel spacer. Tried to find thier directions but didnt come up with much...
Thanks

 

[493 Mike]

No dumb questions here, maybe some smartass answers! I have to believe .030" is plenty of clearance for a pair of rocker arms. You need enough that heat expansion won't cause issues.
Mike

 

[Mike67]

No dumb questions here, maybe some smartass answers! I have to believe .030" is plenty of clearance for a pair of rocker arms. You need enough that heat expansion won't cause issues.
Mike

Thanks Mike!
That's what makes sense to me but sometimes I don't have enough sense to make change for a dollar!!!

 

[4mulas]

I call the manufacturers of most parts I have questions on before relying on a lot of different internet opinions. I bet they’ll be able to tell you exactly what they mean.

 

[493 Mike]

Thanks Mike!
That's what makes sense to me but sometimes I don't have enough sense to make change for a dollar!!!

Why, that's just nonsense!
Mike

 

[wyrmrider]

for SBM especially with W2 or other way offset rockers torrington bearings help friction and heat and prevent brinelling of the rockers

 

[Blake67GTX]

Mike 67,

I used P/N 1621-16 Comp Cams Roller Rockers on my 440 RB...I purchased the kit with Comp Cams provided shafts, spacers, hold downs, shims etc.

We used .030" total clearance between the provided hold downs. We used a .030" feeler gauge to ensure proper clearance. We found that, on my Indy aluminum SEZs, we had not enough clearance. It was pretty much a squeeze getting everything in. Too tight.

So, I actually took a die grinder and carefully ground the mating side of both steel hold downs to achieve .030" total side-to-side clearance. Removing equal amount of material per side (approx)...For fine tuning to finished size, I polished with 400 grit sand paper and WD-40 (I figured...why not?) However, I did spent all night grinding, polishing, measuring, re-fititng and re-measuring. Rinse, lather, repeat.

I have roughly a couple hundred miles on the motor and about 30 1/4 mile passes so far. Nothing looks out of the ordinary and nothing sounds sloppy.

Periodically, I pull the valve cover to inspect and it all looks okay so far.

In conclusion, I think they're a nice rocker arm. They seem extremely strong and durable. Maybe on the heavier side, but they're a nice set.

My 2 cents.

Thanks,

Blake

 

[PRHeads]

.030 per pair is waaaay enough clearance.

.012-.015 per pair is really plenty.

 

[BSB67]

.030 per pair is waaaay enough clearance.

.012-.015 per pair is really plenty.

This. I think if you are using aluminum hold downs, with expansions things start getting tight at 0.008" or 0.010", IIRC.

 

[Mike67]

Thanks for the replies. My rockers are the 1621s and I mispoke the hold downs are the Hughes billtet steel ones.

 

[justcruisin]

I have run PRW stainless for 7-8 years with steel hold downs, similar to the comp pro magmuns, pairs are at 0.015", some a little under, never had a problem.