Question about my 461 SBC head studs an Nut's. Do the factory press in rocker studs have a special thread? I replaced all my old stock rocker Nut's with new factory type rocker Nut's because the original set the machinest put back on were very loose and would not grip the studs any more so i thought maybe its because they were old and they needed replaced. But the new rocker stud Nut's are just as loose and don't grip the rocker studs anymore then the old ones did. I remember the machinest telling me he cleaned up all the rocker stud threads. So did the cleaning up of the rocker stud threads cause the rocker Nut's not to grip anymore?? I'm sure I will have to replace the press in studs with new screw in studs. But I'm curious to find out more about the factory press in studs and the screwed in studs are the rocker arm stud threads different then say a standard bolt thread the same size as the rocker arm studs ?? And do they need a special die threader tool to clean them up?? Thanks again all your help is appreciated. (And please excuse me if I already asked about this before, I honestly can not remember if I did??) 1Nimrod
Do you mean that the rocker nuts won't grip the studs? if so, did you replace the nuts first and see if that would fix it?
I never really gave the studs any thought, but yes, the 3/8-24 thread could have a better thread class than a typical 3/8-24 bolt. If the factory threads were produced with a better fit running a standard die over them to clean them up may have taken a bit of material off them. Also, I imagine the new nuts you bought are rocker nuts as those are pinched in at the top to hold the valve lash correctly. If they are correct you should be able to run a nut down by hand until it reaches the top third of the nut. At that point it must be too tight to run down by hand. In the photos you can see the out of round threads that cause the nut to grip the stud tightly. Those three triangles are where the nut is pinched.
reading the original post again, I think my confusion comes from him calling the rocker nuts "bolt's".
If you are going to run a high lift camshaft, press in studs are a big gamble. Heck, I've had press in studs work loose in a stock 350. If it's a borderline cam you might could get away with it in a Ford but I would put screw in studs on a Chevy for the reasons above. BTW, there's more to it than simply running a tap down the hole.
squirrel; Yes that's exactly what I have done. I bought a new set of rocker arm nut's and they are not any better than the old ones. 1Nimrod
Squirrel; My bad "No Excuse" for me calling the Nuts Bolt's. Just plan wrote it wrong I'm sorry... 1Nimrod
Try some polylocks: https://www.summitracing.com/parts/...MInfqpyb_S4gIVCdtkCh1NvwokEAQYCCABEgKi4fD_BwE
well, now that we understand what you meant, it's ok. Are you using stock valve covers, or covers with room for taller nuts, such as polylocks? https://www.summitracing.com/parts/cca-4604-16/overview/
Squirrel; I will be running the after market Valve Covers hopefully they will be tall enough for the polly lock type Nut's. I've been reading since midnight trying to find any information about the Rocker Arm Stud thread's and just now my Son-in-law told me he found information saying "The Rocker Arm Studs should NEVER" have a die cutter put on them because "The Factory has Special Rolled Threads on the Rocker Arms Studs" So if the machinest used a Standard type Die Threader for common type bolt's or Studs then that like Fordors said could have taken off the Rolled Threads or to much metal off the Studs causing the old and new lock Nut's from gripping on to the studs. Hope I wrote this better than the first post ???? (I don't know the proper name for the tool that make or clean up the studs or bolts threads) 1Nimrod
A "die" is used to cut threads, and a "thread chaser" is used to clean up threads that are already there. The info you quoted does sound correct.
Fordors; Yes the New Nut's are the same as the old factory Lock Nut's having the same three crimp marks on the top of the New Lock Nut's. My Son-in-law found information for me did you read my other post I put up? 1Nimrod
I will start with this disclaimer- I have never used poly-locks on an engine I built for myself. With that said here is what I always heard- poly-locks are really efficient if the top of the stud is perfectly flat and the set screw can get a good bite. Aftermarket studs will have a ground surface for use with poly-locks. Maybe they will work on stock studs on a low RPM street driven engine, but again, I have no experience. If others agree they won’t work well with the stock studs then your alternative will be screw in studs and that will require removing the old studs and tapping the holes for 7/16-14 thread. If your heads are in good shape and ready to go that might be your best alternative. There is a good, economical set of studs on eBay and if you provide the muscle you can do this at home. Another plus is you can use those new rocker nuts you bought.
When I ordered my heads from Dart, I specified the 7/16" studs, of course screw-in type. The ends were ground, I believe they are an ARP item.
I have done it on the bench and even in the car on a blown 350 Corvette, but the key is using the right studs. Here are photos of the correct studs to use and the tapping block to maintain proper rocker geometry. I do agree, if the new studs have an integral jam nut then the bosses need to be milled, but the stud pictured has a small area above the 7/16 thread to lock it against the head and the threads are rolled on both ends, not die cut. These studs will be perfectly fine for anything the average guy will throw at them. Look here, scroll down to Post #3- https://www.jalopyjournal.com/forum/threads/sheared-rocker-stud-disaster.1115766/#post-12662292
Just do it the easy way that they did back in the day. Tap the studs down solid then just cross drill a small hole across the stud and boss and pin it. Simple and cheap and done tons lots of heads in the old days. Like stated above, use poly locks or sure locks by Mr. Gasket, never build a motor without them. Just take a 4" grinder with a flap wheel and clean up the top of the studs and your good to go. A really good trick on poly locks is set them up BEFORE installing the intake manifold. Get a small paper clip and bend a small "L" on the end. Tighten the poly lock until you can just slide the small paper clip L between the lifter plunger and retaining ring and tighten it down and call it done, now of course you want the lifter on the bottom of the cam lobes when you do this. But I set every motor I've built this way and never had to readjust the lifters.
I've got an old kit they used to sell for that. I see it every couple of years when I am looking for something else. But pinning the studs won't fix the problem of the nuts having a loose fit on the studs.
Pinning won't fix the loose fit of the nuts, but if he replaced the studs, he could pin the new ones to be sure, then use regular rocker nuts, or poly-locks, or whatever fits. The fit would be restored.
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