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I have a set of heads for a Pontiac. These have screw in threads. All the rest I have are pressed in studs. My new threaded studs will go down all the way except the last 1/8 inch. The tapped threads are not quite all the way down. I would say my tap will bottom out before I'm able to tap down any further. Do I take my cut off wheel and cut the threaded studs? 16 of them. I don't think washers are the answer due to the adjustment for the rockers. Thanks Dave in advance.
bbc rocker studs put a nut on them trim the stud back unthread the nut that way it cleans the thread as you take the nut off and give you a good line to trim to .could tap them with a bottom tap but you Do Not want them dead heading on the bottom this will break the stud tower of the head
Thanks Pat. I think that is my only option. Glad you mentioned the nut. I do get into a hurry at times.
well your not done yet you want to try to center the new stud so the rocker ball rides on the stud and not the threads so you may want to check that. if needed i use ARP stud washer to center the stud or a thicker washer there ground so stack two if needed or i get super thick grade 8 washer and face them so there flat use loctie and your good .but if you use poly locks make sure they clear your valve coversQuote:
Originally Posted by Trjohn57
These are ARP studs. I don't have the nuts yet. I do see that they are different than my pressed on stud nuts. I understand that the balls have to ride on the smooth part of the studs or the threads will ground down and metal filings are not a good thing.
After my brain started to work, I see what you meant. Thanks again.
Pat/Trjohn57,
Can you help me understand? :confused: The concern is the bottom threaded end that threads into the head, holding down the pushrod guide plate and providing a more secure base than a pressed in stud, right? As shown it is bottoming out before it's tight which will tend to break the stud tower on the head. So is the answer to trim back that bottom length so that the hex bottoms out on the pushrod guide before it bottoms out in the hole, or are you saying that you use the ARP stud washer(s) beneath the hex to provide that clearance, plus raising the stud to center the rocker ball on the non-threaded part of the stud?:confused::confused: Just trying to follow the process for future reference.
My threads in the hole are not threaded allt he way down. The tap will bottom out before it makes the threads all the way down. So I will be cutting the studs down 3/16ths of an inch so they press on the guide plates. Like Pat says that if I try to make more threads in the hole then I might break that area. I see what he means about using washers if the rocker balls ride on the top threads. I'm getting ready to cut the first one.
Thanks for the added info. So you trim the studs, then after you install & adjust the rocker's you make sure the rocker balls are riding on solid stud and not threads, and if necessary you can add a Grade 8 washer under the stud to raise it up, right? If it's riding too high on the studs for a washer or two to get you on the solid stud, would that point to the need for a shorter pushrod? Why not just start with a washer, and then trim the bottom only if your rocker ball rides too low up top? I'm not questioning the process - just reasoning and asking questions.
I cut once and had to take alittle bit more off to get it to press on the guide. Worked great. 2 down. 14 to go. I appreciate the help.
Just like all the high performance parts--take them out of the box and bolt them on!!!!! (yeah, right):LOL::LOL:
I understand what you're saying. I would have to start out with a washer that is over 3/16ths thick. I won't really know what's going on till I install the head. Atleast this way they fit and once the head is on it's probably easier to add after that. There should still be enough thread to do the job. Scary in a way. Still trying to find the correct nuts. These ARP studs are 290-7201. Been looking for a matching nut number, but haven't found that yet. I might have to make a call to let them know the number so I get the correct ones.
Just like used parts. This guy said this alternator bracket came off of a 70 pontiac with ram air 3. Shouldn't be any different than my 69 or 71. But of course it won't work. No way it mounts to my waterpump.:(
These heads normally have pressed in studs. I have the same set on the GTO. I wish they would have left that alone and not tapped them. But there are all sorts of obsticles when your going from scratch. These are #66 heads. On the 455 they make 325 hp stock. I'm putting these on a 400 ci motor. I will have to get different pistons due to the 114 cc. Fingers crossed all the time on this deal.
OK, that picture of the two studs tells the story - that lower end is about twice the length I would have expected, judging by the picture. Thanks for taking time to post the added details. I hear you on the used parts, too - that "Shouldn't be any different..." covers a wide range of misses.
Nowhere in this have you explained what tap you are using--of course a NORMAL tao will bottom out before it cuts threads to the bottom of the hole--however there are several styles of taps and they all are for specific purposes--have you used a bottoming tap , that cuts threads closer to the bottom of a blind hole???I quite often end up using 3 different taps on some of these projects
These were tapped before I bought the heads. The taps that I have won't do the job. They are your normal Sears taps. I feel comfortable with cutting the studs down. Thought about grinding a tap down, but I'm not going to do that. Chances are that I'll get the washers. Only if the clearance isn't there. I haven't changed anything on the top parts of the stud, so they should still work right. 8 done, but one still needs to be grinded down a little. Thanks again guys.
IFIFIFIF----IF the holes are deeper than the length of lower part of the stud, you are giving up probably 1/3 of the strength available from this modification be cause you only have a sears tap!!!!!
measure how deep the holes are, and the length of the lower stud--if the holes are deeper than the stud length, you need to get a proper tap and do the holes---
I would say they didn't use the correct tap to do the job. Hole depth 1 1/16th. Stud 1 inch. I can run my tap down to 1 1/16th, but it's not the correct tap. I'll do some checking to see if I can get the right tap before going any further. I could try and grind my tap down, but I'll look first.
Found the bottoming out tap and possibly a stud kit so I can get the nuts with the studs since I need them. I'll just go that route. Not to bad a price on both. Just waiting for a picture of the parts on the kit before I purchase them. Really want to say thanks again.
This I copied from McMaster-Carr cataloque about tapers on taps
Chamfers
Taper
Plug
Bottoming
The chamfer is the reduced thread height at the front of the tap that guides the tap into the hole. There are three types of chamfers:
Taper Chamfer—Has 7 to 10 chamfered threads. Use for starting threads and in through holes. Requires less torque than other chamfers.
Plug Chamfer—Has 3 to 5 chamfered threads. Use in through holes as well as in blind holes that have sufficient space at the bottom for chips to accumulate.
Bottoming Chamfer—Has 1 to 2 chamfered threads. Variations of the bottoming chamfer include semi-bottoming, which has 2 to 2 1/2 chamfered threads, and modified bottoming, which has 2 1/2 to 4 chamfered threads. Use in blind holes where threads must come as close to the hole's bottom as possible.
Always bought mine in sets of three. McMaster - Carr is where I buy them..
I did buy a Blackhawk tap today. Since there are already threads tapped, this should do the trick. :)
LOOKS LIKE ALL HELL BROKE LOOSE HEAR? your not loosing any thing cutting them studs down that much. i am doing a 455 stroker heads studs are out of the heads and are just stock bbc were the ARP you have are for more like a alum bbc head long as you have 7/16 to 1/2 going in the head your fine
What I was taught you don't need much more than the dia. in the hole to hold.
in ALUM head you want all you can get but there not Alum and them studs are longer then stock bbc that what i have used in the past and what s at the shop now .that i am working on now with a 680 solid roller cam . what come in to play is the base /shoulder as well on the stud the base keeps the rocker from pulling the stud over but that s not going to happen on a mild build and you could EZ get away with 7/16 EZ as the dia is 7/16Quote:
Originally Posted by cffisher
Should be ok then. I bought the tap so I'll tap the other head. I think it's around 60 for the nuts alone. But I see I can get a kit for 85. I'll have to find the 7/16th nuts yet. I walked away from the heads earlier today.
if you need poly locks i have them or use a bbc stock nut . you can tap them deeper but you have the wrong studs to long no big deal cut them down this is no big deal have to make stuff fit all the time
Sounds good to me. I'll just buy the rocker nuts then.
South Dakota has no snow on the eastern side. Somethings wrong here. Maybe that's been my problem all the time.