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1.6 roller rocker hitting stud vortec

20K views 62 replies 12 participants last post by  99 to Life 
#1 ·
hey guys, tried searching on here for this problem, really didn't come up with much, except I did hear a few guys mention clearancing the rocker. My problem in a nutshell... I know my max lift with 1.6 rockers should be .525 without even dealing with the pushrod (another topic), the back of the roller rocker is hitting the poly lock on the stud. So pushing my valve down (checking springs) by hand I have a total of .595 clearance bf the retainer hits the valve guide. When I have my rocker on and push it by hand it only goes to .470. So I'm short by .55 thousands. (.525-.55=.470) Question is, should I clearance the rocker (don't wanna do) or would a longer valve help? I hate to have to buy new rockers cause I'm broke and trying to wrap this engine build up. Also as of right now the stock vortec pushrods of 7.125 are way short. I have a pushrod checker, but everything I read on this is "your pushrod is too long" so thats why I didn't even bring that in to play, no pushrod in the test and my rocker is hitting the poly lock. I can try and get some pics, but I don't have em on this cpu at the moment. Any thoughts on what I can do to get the clearance I need. Thanks
 
#2 · (Edited)
So is the cam a roller lifter or a flat tappet? Stock roller pushrods are 7.200 and flat tappets are 7.800

If you're just letting the back of the rocker drop and screwing down the polynut all the way, then the rocker will be at such an angle that it will hit the polynut or the stud.

You really need to use a pushrod of some sort to at least be in the ballpark and knowing what type of lifter you're using will help even if it's not perfect.
 
#3 ·
czar, thanks for the reply, I did have the checker pushrod in there. Yes full roller set up. hotcam with 1.6 rocker .525 at zero lash. Here is a pic of the geometry with the pushrod checker. Stock pushers I'm measuring 7.125. The pic here with the checker, I'll have to measure again, cant recall but they are like 7.5" I think, seemed like a huge jump. I'm running 1.800 tall 7/16" screw in studs. I really don't see any length pushrod solving the problem, that why I was pushing it by hand, but have checked it with different push rod lengths.
 

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#5 ·
ok, see I originally had screw in studs that were for guide plates, quickly found out they weren't gonna work, and found studs that were fully threaded under the hex. So really I need shoulderless studs? How would you torque those? I'd run a nut to till it bottoms out then torque it?
 
#17 · (Edited)
ok, see I originally had screw in studs that were for guide plates, quickly found out they weren't gonna work, and found studs that were fully threaded under the hex. So really I need shoulderless studs? How would you torque those? I'run a nut to till it bottoms out then torque it?
If you plan on using a stud like this DO NOT torque it down to the normal 55ft lbs! You will split the stud boss......I guarantee it! I would rather have my pressed in studs pinned then usethisgarbage. If you are going to use these studs I would seriously suggest just to snug then up and then pin them with a 5/32 roll pin. Seal them up with a good thread sealer (not loctite, the **** don't work, I guess maybe in a lab where every single thing is perfect)

Again if you torque them studs I guarantee you won't like the results. And leave the loctite at the store.
 

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#9 · (Edited)
As mentioned by ericnova72 this is what you need; see picture. Install with doubled nuts to lock them to the stud so you can torque it use red Locktite on clean threads. Another way is to buy a 3/8ths fine 24 thread/inch coupling nut; screw it about half way on the stud then run a matching threaded bolt down till the bolt and nut lock with each other then pull it to torque then holding the coupling nut with a wrench to prevent it turning, unscrew the bolt then remove the nut <<< >>>. Or use a poly-lock. This does away with having to buy a tool, remove heads, mill chips everywhere or send to shop, clean and reinstall. Most every parts outlet lists these things they are not expensive like 10 bucks see here <<< Screw-In Rocker Studs, 3/8 Inch - Speedway Motors, America's Oldest Speed Shop >>>

You will either need heads that have the guide slots in them or you will have to use self guiding rockers as these shoulderless studs cannot position sheet metal guide plates. If you need sheetmetal guide plates for the push rods which need to be the hardened type then you're back to milling the stud bosses. At the machine shop that should be less thana 100 dollars so by the time you buy the cutting tool you've spent about the same and didn't risk leaning how to use it by messing up a boss or two.

Bogie
 

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#8 ·
As mentioned above....Shoulder-less stud is what you need if you aren't going to mill down the stud boss for the hex stud.

Install the shoulderless by using two nuts tightened into each other on the fine thread rocker end of the stud, install stud into the head with threadlocker compound(loctite) or at least a sealer like rtv silicone, as some of the studs go into water passages under them. Remove the nuts and on to the next stud.

You may be able to use the polylock nut locked to the stud to do this, but the double nut method will prevent wear and tear on a polylock.
 
#10 ·
cool thanks fellas, wish I woulda caught this before. But hey atleast I didn't buy my pushrods yet. I always thought you needed to mill that down for the thickness of the guideplates, thats why I found these studs that are fully threaded so they thread flush to the stud boss. But its all clear now, I'll order them up so I can proceed. This is my first time using studs and roller rockers. I'm pretty sure on most of it, except the darn studs which isn't hard to understand.
 
#14 ·
this is my go to site on engine questions, however dunno why I just always read or misread that you need to mill down the whole hex thickness. Now I know and atleast it isn't a big expense. Thanks for the replies guys. I'll post more when I finish up the engine and or if I got any questions before I do. All I got to do now is pushrod length and button it all up. Its a full roller carbed vortec sbc 9.5:1 static compression, running the hotcam with 1.6 rockers. Should be fun.
 
#15 ·
Those look like the same $100 ebay rockers I tried to put on a guys engine a few months ago. I had the same problem with the polylock relief in the rocker hitting on the polylock before full lift.
Confused me at first as I was checking piston to valve clearance and really didnt expect an interference issue. I sold the guy some Comp steel rockers and let him have his ebay rockers back.
 
#20 ·
I'm referring to the ones you are calling shoulder less. I look at these studs as a quick way to repair a pressed in stud that has been pulled from the engine. What you are wanting to use them for is a crutch and a cheap way out. Do it right or just don't do it. Comp cams sells a stud boss cutter for doing this. With careful setup and execution they can be milled at home preferably in a drill press.
 
#21 ·
I appreciate the input, A. I am actually looking right now for 7/16 7/16 shoulderless studs, can't find any. I wouldn't be afraid of running them to be honest. Anything is better than the pressed in studs. Sure will some of these crack possibly, I wouldn't doubt it, anything is possible. I don't see how cutting a boss and then torquing a hex head is gonna have any better chance of not cracking a boss. I'm open to that can of worms, I'v done neither but neither seem to scare me. Yes I'm trying to keep costs down where I can and spend as much as I can on more critical stuff than others.
 
#23 ·
well either way I gotta spend more money which I just hardly have right now. They don't seem to make a non shouldered 7/16-7/16 stud. That would let me keep it moving on the cheap, but thats not an option. So I'm gonna call the only machine shop I know and get a price, and or just buy the tool and do it myself so I can use the studs and rockers I have. I have 2 more sets of these heads, so I don't mind having the tools to do this stuff myself.
 
#24 ·
Dorman Double-Ended Studs 675-042 - Free Shipping on Orders Over $99 at Summit Racing I'm not saying these studs will work I'm just throwing these out there for an example. They are just a universal grade 8 stud. If you spend some time at a real parts store (Napa, auto value) flipping through catalogs you should be able to find a stud that'll work. I would still suggest doing it the right way by milling the stud boss.
 
#26 ·
thanks guys, wow I searched all over summit and I'm a good searcher I feel, you def beat me on that. Glad to find that, but sux they sell in sets of 10. Still pretty cheap. I'd like to get tool since I have other heads, and I'v actually been looking for a drill press. I'd like an old delta or something good and old, not this new garbage. But that requires money and right now I'v struggling trying to finish this engine and finish my project, unfortunately every penny counts. I don't wanna skimp anything though, so we'll see how it goes. I appreciate the input guys.
 
#27 ·
If you work carefully this can be done with the tool and a hand held electric drill. The tool pilots in the boss so you get a pretty decent basic alignment that cuts the boss square to the hole such that the hex seats across all the available area. Height wise this needs to be pretty close but we're not talking holding thousanths of an inch here. A drill press is nice, a milling machine better, but if you're willing to take your time and pay attention to what you're doing you can do this yourself.

Figure the tool will cost about 75 bucks and a lot of time and a darn good electric dill if you don't have one. Getting a decent drill press will set you back 3-4 hundred bucks and that's probably a Harbor Freight cost, don't worry about name brands they get theirs in China too they just charge more. A shop with all the right equipment would charge about 200 dollars, maybe less since they don't have to pull the old studs out and you don't risk the heads to your abilities as a machinest.

I'm still up in the air about how you guide the push rods, question is do the heads you're using have the factory lozenge shaped guide in the casting?

Or are you using self guiding rockers?

Or are you using guide plates that fit under the stud hex?

This has to be worked out before you start cutting on the heads.

Bogie
 
#28 ·
bogie, I'm using self aligning rockers, I opened up the pushrod hole with .5" drill bit for the 1.6 ratio rockers. I'll prolly try and get the tool and a CL drillpress, I find them almost every week, just been broke lately. As I said, I have more of these heads that will go on some future builds so really I like doing what I can in house and save costs where they can. thanks for the comments and suggestions guys.
 
#30 ·
while were on the subject oes anyone remember a tool from the 70's and 80's that was use to cut the stud bosses down with a 1/2" drill. What was different about this tool was it piloted off the old pressed in stud. I want to think it was adjustable to where that once it was set the top of the stud bottomed out in the tool when the boss was cut to the correct height. An added advantage was that once the boss was cut the ol stud was easier to pull. Anybody remember this? is this tool still available anywhere?
 
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