I've had the Comp Magnum rocker arms on the 396 since 1997, but even when first installed I wasn't particularly impressed with the locking feature of the provided nuts. They were generally better than the 30 year old stock ones, so I used them. Two weeks ago at the track I noticed a rocker tapping, and finally got around to checking it out yesterday. #7 exhaust had backed off, and the lock feature was barely gripping.

Being the 4th of July, the "major" parts stores weren't open, and I couldn't find just nuts at the chains. I ended up spending 2 hours driving around town to chase down 5 rocker arm kits to use the nuts from (at one store, 3 kits were already missing the nuts). Two of the kits I got were TRW, the other 3 Speed Pro, but with the same p/n's. The former weren't much better than the Comps, but the Pros seemed better. I ended up replacing 4 nuts as I adjusted the whole engine.

Just curious if anyone else has seen this issue. I'm inclined to get a whole new set and replace them all, if I can find something decent. If I go with the solid cam I've had my eyes on, I definately don't want to have nuts that don't lock properly.

I've switched nuts between studs, and the locking strength followed the nuts, so I don't think it's a stud problem.

 

I am using Crane Kool Nuts with my Comp Magnum's and haven't had any issues so far...

 

did you tighten the set screw then tighten the nut just a bit more?

 

These are self-locking nuts. 11/16" hex, no set screw.

 

You can often save a GM rocker nut by locking it in a vise and
stricking the top with a hammer and center punch to "tighten it up". ( see the red dots) Stock, Speed Pro or Crane nuts will work fine for a solid lifter cam. But you need to check the stock rocker to stud clearance unless you have "long slot rockers", when installing a higher than stock lift cam on a big block with stock type rockers. The rockers can be ground for extra lift travel clearance.

Many people use a impact gun or air ratchet to remove the nuts during a teardown. A big no no. The nuts' built in resistance is destroyed by the heat buildup that occurs by using air tools to remove or install them.

Again, heat is what destroys the lock on these nuts. I'll beat money that if you were to run a can of GM "EOS" in your oil regularly, you would see much better life out of the rocker nuts (the stock type ball stud rocker will run cooler) Your flat tappet cam and lifters will last longer too.

 

Woops forgot the pic...

 

A jam nut on top wouldn't help?

 

No

 

Except for break-in periods, the engine has had nothing but AMSOIL run in it. I have a hard time imagining a GM additive reducing ball heat build-up further.

The locking feature wasn't too crisp at install. Weakening from there isn't too surprising. I was wondering if it was an artifact of Comp's product quality 8 years ago, or something more common. I prefer replacing over whacking.

Magnums are long slot. Lift at the valve is only .510".

It must have liked the fresh adjustment. I took it out to T&T last night, the first run off the street was the 3rd best it's done at altitude. The 5th and 6th runs were best ever at altitude, even though DA was over 8500'.

 

Five seven: Give the GM EOS a try . it has ainti wear and anti scuff chemistry in it that are not in oils sold over the counter, even AMSOIL. It is highly recomended, still as the only GM tested effective anti wear additive by GM engineers for the last 40 years. It is also highly recomended by many camshaft manufacturers for any one running a flat tappet cam. (Crane calls it "Crane Super Lube")

Direct oil lubrication is essential for a ball stud rocker to live. its also essential for valve springs to last. (the oil cools the spring) If you're not
using factory valve covers on you big block with the factory oil drippers in place, you might consider finding a set and switching ( back).

I have had many good big block cars in the past. We're going back 30+ years. Learned a few thing about what works and why they (GM) does what they do (did).

Amsoil is nice oil.... try the GM EOS. Its actually cheaper than most of the miracle stuff in bottles you see on the shelf at the auto parts store. Solid engineering there.

 

I have no clue what you're talking about there. I've been running the stock '66 valve covers, there isn't anything but baffles for the PCV/breather underneath.

 

Most of them have the drippers in them. My earliest BB was a 68, most were 70's era.

 

....

 

Just in case you're interested here are the factory valve covers with the oil drippers

BB Chevy valve covers with drippers
$89.95
*1210
New chrome valve covers will fit the BB Chevy 1965-up 396-402-427-454 engines. These exact reproduction covers offer the highest quaility chrome plateing in the industry, correct wire stands and factory oil deflectors "drippers". Available with recessed corner or without recessed corner. Will fit all big block engines, Camaro, Chevlle, Impala, Monte Carlo, Nova, etc. Now available in "raw" un-plated

Source :Noah Performance