r sbc rocker arm studs opposite thread? i was breaking in my 350 this morning and #1 exhaust stud broke a clean line of a break. looks like a defect. i need to remove it. i welded a nut to it but it broke below the nut. thats why i'm asking if they are opposite threads. i wasa able toweld the last nut on, and i need to know. before i break it any further down. JAN
They are pressed in, not threaded from the factory. That is why it snapped when you twisted it. Needs to be pulled out with a puller of some sort, now that it is broken off. Don
yep, stock studs are pressed in, and all of the aftermarket studs that are screw in that I have seen were regular right hand thread. The press in studs are a bear to pull out ...
Jan, I will answer your PM here in case anyone else ever runs into this. You say you feel your studs may be screw in because they had allen heads on top, which I interpret to be for roller rockers. If that is the case, there should be a hex head at the bottom of the stud where it seats up against the head boss where the stud enters. Usually that hex head is turned like a bolt, until the stud seats into the threads that are needed to be tapped for this purpose. There may be screw in studs that have no hex head, but I have never seen those. But there are lots of things I have never seen. Maybe that is why your stud broke, were you using the posilocks with regular rockers ? All the screw in studs I have used had regular right hand threads. Don
Aftermarket screw in studs generally look just like this and have that distinctive hex head at the bottom to facilitate installation: Don
There were screw in studs without a hex. They were right hand and had a small shoulder that stopped at the top of the stock unmachined boss. If they are press in make sure they are not drilled and pinned.
They do make screw-ins without the hex-shoulders. I think speedway sells them, or used to. You could also find them on ebay. I use them to replace press-ins if a pressed in one gets pulled out. The ones that I have come across have a 7/16 course thread that goes into the head and the rest of the stud is 3/8" regular style. I have also seen the straight 3/8" style. All of the ones I have seen or used are right hand thread pattern like you'd expect. Not reverse. As to whether or not the ones he is messing with are threaded or pressed, if they have the allan head, I would ***ume threaded. Unless he has posi-loks and roller rockers that just make it look like they are allan head.
You guys bring up some interesting points. They could be stock press in studs, or stock press in studs that have been pinned to keep them from coming out. Look on the stud boss to see if there is any evidence of a hole being drilled straight through the boss and the stud . Shoot us some pictures of what you have, that will help. Don Here is a screw in stud (and valve) that snapped off in the 306 Ford in my Son's T bucket. All we had to do was unscrew the stud, replace the valve, and it was back on the road.
i don't know what this is, it was a project that i bought in Conneticut. there is the rocker and the piece on top of the rocker inside, then the adjusting nut 5/8th with an allen as the locking. there is nothing that i can see on the stud. say if they are pressed in what kind of puller can i get. i got a nother nut welded on the last of the threads. if i need to [pull the stud i need that nut for pulling. oh it is a 3/8 fine thread stud.
Does it look like the nut in the picture Don posted? If so undo the allen head screw and then back off the nut.
+1. If it is this style, the allan head locks the nut. Not the stud. As for pulling, if you have enough meat and thread left, you can stack wasxhers and use the nut. Tighten down the nut and add washers to pull it up after backing it up each time. If it's too far snapped off..... you could try drilling it out if you can hit it right. Other than that you will likely have to weld on something with threads on it to the stud or nut and then pull it out. Or get creative building some sort of tool. A picture or two would help
This is what stock press-in studs look like. http://i148.photobucket.com/albums/s26/sateen501/IMG_0432.jpg It was drilled for a pin, and the owner ran safety wire thru the (roll?) pin for insurance because he was unable to peen or stake the pin or boss to help retain the pin.
I have been building race big block and small block Chevy's for 40 years. I am well aware of which is which, but it doesn't sound like the O/P does so I was tring to get a feel for what he was talking about.If the stud has an allen key in it then it is clearly a screw in stud for a head that wasn't machined for guide plates and screw in studs with a hex.
If it IS a press in stud (not pinned) it sounds to me like all the threaded part of the stud is broken off. What I would do is remove the nut you welded on, taper the end of the stud, take a grade 8 3/8 bolt and cut the head off, taper the cut off end of the bolt, and align weld the bolt to the stud. That will give you threads on top. Make sure it is a really strong good weld. Now, Slip a deepwell socket down over the stud with the square part up (1/2 inch drive) to act as a spacer. Then stack washers on top until just about 6 or so threads are showing. Put a 3/8 regular nut on the threads and start turning with a rachet. What you made was a shadetree stud puller and by tightening up the nut it should extract the broken stud out of the hole. Go slow and pull straight. You might have to put a washer on first so the socket has something to lay perfectly flat against. Once it starts to come it will be much easier. Buy a new stud, put red lock***e on it to secure it in the hole, and you should be good to go. But you still need to determine why the old one broke, so your pictures will help. Don
^^^^^^ What Don said also if there is enough stud sticking out you could grind a champfer and try running a 3/8 fine die down and doing the same with the nut and jacking it out.Worse case scenario I know most, and I am pretty sure all go into the water jacket. You could cut it off flush and drive it into the water jacket. Just saw the picture looks like press in studs I think it's to short to run a die down try like Don suggested or cut off and drive in.
Pretty sure I see no threads cut, so they are probably stock press ins. BTW, you have a mix of parts there that really aren't right. S**** the polylocks and get simple stock Chevy adjustment nuts. See how far down in the hole your allen is ? That is because the polylock is just catching the very tip of your stud. If it doesn't seat down further you will keep breaking studs because all the strain is on the tip of the stud. There is no reason to have polylocks on those type of rockers. Don
DON ill change them out. now about getting it out. i got a nut welded on it. any ideas on pulling it. really don't want to hit it in.
You could get a 3/8 fine bolt and do like Don suggested in reverse, grind a point on both and weld it with the threads up and jack it that way.
Ding, ding ding, we have a winner. It's probably going to be really difficult to run a die on the broken stud. Cut if off, level with the boss, and drive it into the water jacket of the head. Replacement studs are made in stock and oversize diameters. The broken/driven in stud won't interfere with anything, but it HAS to be short enough, so when you drive it into the water jacket, it does't pierce through anything. You can buy liquid nitrogen now in drug stores for wart removal purposes. Perhaps you could use it on the broken stud ONLY to make job easier. There is also a device sold just for the purpose of removing broken studs; it has a serrated, cam-lock type mechanism, that grips the stud, but it's really no different than welding a nut to the stud. I think I would try the nitrogen trick first, at least to get it "moving". Butch/56sedandelivery.
Good to know those studs go into empty water p***ages. If that is the case, do what the guys are suggesting, use a die grinder with a cut off wheel, cut it flush, and use a drift punch to drive it all the way in. It will not hurt anything being in there if it is that short. If you still want to pull out the stud, the only way I know with that little amount left is to weld on a stub of a bolt, then use the socket and washers as I mentioned. They pull out pretty easily once you get a straight pull on them. I have been thinking about what caused your breakage. Two things come to mind. First of all, the polylocks not fitting on the stud as I mentioned earlier. Secondly, if you are running a high lift cam the slots in the rockers may not be long enough to let the rocker move freely on the stud without bottoming out during it's travel. Your pushrods may be too long too, which causes the rocker to be off the end of the valve tip via bad geometry. Don
Post #18, third pic. Don't I see a pin in that stud boss? Did I miss where someone told him how to get that out, before doing anything else?
Shouldn't he tap on it as it is now and see if it'll go in a little BEFORE he grinds it off beyond the point of no return? Personally I'm of the school to weld a bolt to the nut and jack it out using the socket, washers and nut.
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