Dino_'72

Had a clean snap on number 7 exhaust rocker stud (pics below). Recent retro roller cam change. .510 lift with matching springs. About 500 miles on the motor since cam change.

Heads are 492 camel humps with rocker studs that could be 50 years old. Given age, decided best to change all of them and go with the best and use ARP studs. Simple. Well not really I’m finding out since I want to keep my stock LT1 style valve covers without modification.

The strongest studs nowadays are manufactured with a rolled thread method, and many comments online say you cannot use stock style rocker nuts with rolled thread studs. Rocker nuts must be used with machine threaded studs. However many manufacturers/vendors say it is ok to use rocker nuts with their rolled threaded studs!!

Confused. Research I’ve done below. I just want the strongest studs I can buy that are compatible and work with rocker nuts. Do they make rolled threaded rocker nuts? Would that be compatible?

ARP High Performance Series Rocker Arm Studs

Made from 8740 chromoly steel and are heat-treated to 180,000 psi tensile strength, they are concentric within .005 T.I.R. thread pitch to thread pitch, which will give you more consistent rocker geometry. These rocker arm studs are designed to be used with Perma-Loc adjusters (not for use with OEM-style, self-locking nuts).

My research is that these are rolled threads and using their perma loc nuts will interfere stock valve covers.

Summit Racing™ Rocker Arm Studs

These Summit Racing™ arm stud kits are made of alloy tool steel. They're roll-threaded, heat-treated, and have a black oxide corrosion-resistant finish. They feature larger radius stud fillets for extra strength, and they're designed for use with or without guideplates.

Summit’s Q&A section says they are ok to use with rocker nuts even though they are roll threaded.

Howard’s Cams Rocker Studs

Manufactured from tough 8740 steel, featuring a large ground radius fillet to provide increased support to the stud shank, effectively eliminating bending and subsequent breakage. All studs are precision machined with rolled threads and heat treated for tensile strength of 180,000 PSI then finished in black oxide.

I emailed Howard’s. They said it is ok to use rocker nuts with their roll threaded studs.

Comp Cams Rocker Studs

The High Energy™ and Magnum series studs work well in applications with moderate lifts and spring pressures and are available in the popular 3/8" and 7/16" sizes. When ultimate strength is required, as with high RPM roller cam applications, the Hi-Tech™ Race Stud is the answer. This stud has a thin jam nut for rocker clearance, rolled threads for maximum contact and a ground-flat top so that accurate valve adjustment can be achieved and maintained. The diameter of the jam nut is larger in order to spread the load over a larger area. All COMP Cams® studs have generous radii and a black oxide finish.

I emailed them and have not heard back. All three of the studs types just say made of alloy steel. It’s implied maybe that only the Hi-Tech stud has rolled threads. I called as well. Long long wait times so hung up.

So do I believe Howard’s and Summit and rocker nuts are compatible with rolled thread studs? Maybe I’m over analyzing it? Thanks.

Rescue Rogers

you can use a low profile polylock that should clear the rocker cover. You shoiuld also go to 7/16 studs for the strength you need with a roller cams springs
https://www.summitracing.com/search/...word=polylocks

BOOT77

Poly locks aren't that much taller, sure some brand rocker studs are diff length but you could cut them down(put on a nut, cut off, then clean up end/threads and remove nut). Still if it's a problem felpro makes a double thick cork gasket that has a steel center layer(forgot part number but I have one somewhere) OR https://www.summitracing.com/search/...ll-block-gen-i

Jebbysan

Geta set of Comp magnum roller tip rockers in the 7/16 hole size.....get a set of 7/16 studs.....and a short poly loc as stated.
The Magnum rockers not only are much stronger.....they are a true 1.52 ratio.......stamped rockers can be anywhere from 1.4 to 1.52.....the Magnum rockers are proven the make power over the stamped. After you do lash one time with Poly-Locs you will never go back to a pinch nut. I will not use them or stamped rockers on a high performance build.
You change all of this out and it will be the last time you ever have to.

Your springs are 1.250 diameter......were they spec'd for a roller cam?

Jebby

BOOT77

I'd get some lightweight retainers as well or just go beehive, even GM ditched those big ole things with the vortec & LT1 One of the first things I did to my 86 C4, springs/retainers/seals/pushrods/rockers/studs.

gkull

It appears that you have some upgraded parts like ARP head bolts and the screw in studs and guide plates. But who ever assembled the heads was using 50+ year old thinking.

Springs need oil for cooling. So you throw the spring covers in the garbage. The heavy rotators also go in the garbage. You put on quality light weight chromemoly retainers. Heat and valve train weight are a NO NO for longevity and performance.

7/16th studs are for higher spring pressures of roller cams

Dino_'72

Hi All. Just want to say thanks for all the varied responses and ideas to help resolve this issue.

I still have not had an email response from Comp Cams. So I called this morning Can’t say the tech was helpful. He really didn’t know anything about their studs other than what was said in the catalog. Suggested I go full roller set up. I think a little overkill.

I think I am going explore the 7/16 rolled thread stud route with the crower short poly lock. I really want to avoid any spacers on the valve covers.

Those shields on the valve springs. My fault on those. When I replaced the springs to go roller I just reinstalled them. Did not realize they are not needed and could cause some heat issues. . Makes sense not to use them because I have positive viton valve seals. I do not drive my car hard. So maybe not a huge issue I’m hoping.

See what happens. Thanks for all your detailed responses.

derekderek

as said earlier, beehives. the top of the valve spring is the easiest weight to reduce for the spring to have to close. the less weight, the less spring tension you need. the real problem was 1 tired valve stud. if you just put 16 new ones in, it will probably be fine. but it is hard to justify reinstalling 50 year old valve springs.

Dino_'72

Derek, I don't think I was clear, i changed and upgraded the valve springs to match the roller cam. Based on comments, from what understand I should have got rid of the oil shields and perhaps used lighter retainers. I learned something I did not consider before. Should have tossed those shields at least.

Yes those studs are likely 50 years old like the castings and who knows how many rockers nuts have been on and off chewing at the threads. Snapped clean at the thread base. Will definitely replace them all. The setup and rocker material to be finalized. Cam is not extreme. Roller with .510 lift int and exh . Duration 221 int and 235 exh @ .050. on a 108 LSA.

gkull

Way back when I had a l-82 with 186 double hump heads with screw in studs and guide plates. I went with 1.6 ratio crane roller tips to fit under the stock Corvette cast covers. I had to snap off all the oil splash tabs.

I used the Allen locking rocker stud nuts

Sometimes you have to grind the slots in the guides so that they don't rub on the push rods

Sky65

Wear pattern on the valve looks like the rocker was not centered on the valve? It looks skewed to the side the rocker is laying on. Did you have proper alignment? The rocker is not a self aligning is it?

Tom

derekderek

why 108 lobe sep? that IS somewhat extreme. they tighten the LSA to make up for duration approaching 300 degrees total because they need SOOO much duration to get enough EFFECTIVE duration with flat tappet cams. rollers have much steeper ramps. valves open and close quicker. so you don't need to start the intake opening that soon and leave the exhaust open that late to get to 1 hp per inch like in the old days. 114 is where most engines are set up these days. call it an RV cam. 110 and 112 are where most good performance cams are set up. 106 and 108 are drag strip or idling like a dragster in the parking lot cams.

Dino_'72

Hi All. No rockers are not self aligning. Rockers are not misaligned at least not per my review. Cam on 108. This was the recommendation for my setup as per Chris Straub of Straub technologies. I agree many may think the 108 LSA is not what would be the norm these days. But Chris reassured me with camel humps and ram horns this would work both for some lope at idle and performance. I was worried about drivability and vacuum for power brakes. I have 9.4:1 compression. Result is Vacuum is 13-14 inches at idle (850 rpm) and cylinder pressure is 190. I was surprised. He was right.

Sky65

Good on the rocker on that cylinder. Just looked off in the pic.
108 lobe separation is great on a sbc. That is what I selected based on David Vizard's publications. I have a 355 in my 65 and runs great! It is an everyday driver and a long haul car. It is very streetable and will smoke the 275/50-17 NITTOs from a 10 mph roll to the 6200 rev limiter. No clutch dump, just hammer it. I'm using this Howards cam

https://www.summitracing.com/parts/hrs-110885-08

Tom

drwet

I strongly suspect the slots in your rockers aren't long enough or your pushrods are the wrong length. I made that mistake once with pretty much the same result.

Hopper12

Hey Dino, sorry you're having the issue, but you'll get it sorted. I have a set of sbc poly locks never opened that I got last fall. If you want a decent deal on them, give me a pm and we'll work it out. Best, Paul

Dino_'72

I have long slot rockers and used the Louis tool to elongate the pushrod holes in the head. I need to get a pushrod checker to double check the pushrods. These heads have been milled so probably a good suggestion. Paul, thanks will keep your offer in mind. Had to take wife on a warm vacation, so it will be a couple of weeks before I can deal with this stud issue.

Jebbysan

Good idea....get an exact length....you may be off .050 one way or another.....use Trick Flow or Trend one piece pushrods....
You combine that with the 7/16 Magnum Rockers, ARP studs and poly locs....you will have an anvil of a setup that will last years/miles....strong as ****....

Jebby

HeadsU.P.

Dino,
Your cam lift is not extreme, higher than stock but nothing that even cheap press-in rockers studs couldn't handle.

Your unusual event may have been a fluke, one out of 16, or perhaps some serious binding somewhere. As you already know, binding can & does occur at the pushrod holes in the head, guide plates or rocker arm slots. Sounds like you have all the bases covered. Except one.
The valve guide itself. If at any time the valve is not allowed to close, bam, either bent pushrod or broken rocker stud. (sometimes cracked piston)

Its hard to go wrong with anything from ARP. Superior rocker studs and fasteners. With only 500 miles on this build, replacing all 16 OLD studs is a must. After which I think I would use a valve spring compressor and at the very least, change out the retainers. Stem seals ok? Valves allowed to freely move? Up/down/ spin?
Also, remove one pushrod at a time and roll it on a piece of glass to check for straightness then return to its origin.

Your heads were milled so you know a pushrod length check is in order. The tool for this is inexpensive. Once you get the valvestem pattern tweaked, fasten a piece of tape around the tools adjustment nut so it does not change. Remove tool and measure your NEW length with a caliper. Order rods accordingly and make sure they are guide compatible.

And last but not least, do the rocker ***** have oiling slots in them? If not, that could have contributed to a dry rocker stud.