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Rocker Arm Studs

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Major Nutz

Active Member
Joined
Aug 13, 2003
Messages
697
Any body know what size rocker arm studs are used in GN1's? Pulled the valve cover and found the stud broke at the bottom of the poly lock. It looks to be a 7/16". A part number would be great.
These are the screw in type.
Thanks,
Mike
 
Measure the OD and post or call Tom @ Champion.

I called Tom today, I was just trying to get the ball rolling a little quicker. It turned out to be a 7/16" the same size as a small block ford/chevy.
Thanks,
Mike
 
Mike ARP PN# 100-7101 Chevy7Ford rocker stud kit ...............one broke in the past and i only did one now the other night another broke ..this time im doing them all the One Champion supplied i was told by a machinist is Cheap steel
 
Mike ARP PN# 100-7101 Chevy7Ford rocker stud kit ...............one broke in the past and i only did one now the other night another broke ..this time im doing them all the One Champion supplied i was told by a machinist is Cheap steel

Thanks for the part number. I got replacements from Champion but am having second thoughts on them. As cheap as the ARP are I will probably go with them and replace them all. How much are you torqueing(sp?) them to?

Thanks,
Mike
 
Mike ARP PN# 100-7101 Chevy7Ford rocker stud kit ...............one broke in the past and i only did one now the other night another broke ..this time im doing them all the One Champion supplied i was told by a machinist is Cheap steel



that may have worked with whatever type rockers you have but the part# you listed is 7/16 top and bottom.

I have scorpions and a close comparison with the 2 that i had broke that came from tom was 7/16" bottom and 3/8" top.

I cant prove it (so dont quote me on this)but the measurements and looking at the design with the ones i had looked exactly like trickflows studs that came from tom,

i got the arps my plans are replacing them all,i got 2 replacements from tom and put those on they havent broke for me to change em out yet but i have them in my tool box ready for replacement again if necessary. the part # i bought was ARP #134-7103. hth.
 
The PN is off the package The theaded portion a little longer than the champion one and the bottom part that is six pointed is shorter on the APR stud , one was instaled about a year ago ....they are all in now and will be adjusted and running shortly ......ill take a pic sometime today and im using scorpion rockers
 
ARP on the Left / Champion supplied for Scorpion rockers on Right
IMG_1485.jpg
 
The PN is off the package The theaded portion a little longer than the champion one and the bottom part that is six pointed is shorter on the APR stud , one was instaled about a year ago ....they are all in now and will be adjusted and running shortly ......ill take a pic sometime today and im using scorpion rockers

Ordered them today. What did you torque them to and did you use any kind of sealer?
 
Very nice pics,,, thats interesting mines are a little shorter than yours however im installing mine right now. it looks as if mine will work & will actually sit lower under the valve cover and still shouldnt hit went it pivots. and it will also have full motion swing i'll rotate engine to see...i'll finish sometime this evening or in the morning & if theres a problem which i dont think there will be i'll post back.

i actually like them sitttin a hair lower because when mine broke the first time on the passenger side it bumped up my valve cover and oil went all on my down pipe, engine block starter etc. smokin all the way home luckily i was only 4 miles away from home.


To install Heres scorpions web site for installation instructions for adjusting valves on solid lifter or roller cams:

The most improtant thing to know is adjust one cylinder at a time starting at #1 and work your way around you must rotate engine direction. When the Exhaust valve starts to open on #1 cylinder adjust intake valve when the intake valve open & starts to close adjust #1 Exhaust valve.


Example: When the exhaust valve just starts to open on # 1 Cylinder we will adjust # 1 intake
valve by loosening polylock slightly while spinning pushrod until you feel lash in the rocker
arm spin polylock down until you feel lash go away and now feel the pushrod snug up a little
while your spinning it, this is known as 0 lash now place offset 5/8 box wrench on polylock
facing exhaust side of head at 6:00 position turn wrench ¾ of a turn will put the wrench at
3:00 position Now use T handle Allen wrench and screw the set screw down against the top
of stud firmly then bump wrench slightly tighter to lock set screw DO NOT OVERTIGHTEN
this will split polylock you don’t need much to lock set screw to stud after adjusting put a
magic marker slash across top of rocker to tell you it has been done, now rotate engine until
intake valve opens and just starts to close and repeat adjustment on #1 exhaust valve (note
one Cylinder at a time). Repeat one cylinder at a time until complete engine is finished.
Now it is time to double check starting at #1 cylinder when exhaust starts to open check
intake. New Hydraulic lifters won’t be pumped up yet so you should be able to spin pushrod
with some resistance. Think of a Hydraulic lifter as a shock absorber. And you want to be in
the middle of it, you will be able to push the lifter plunger to the bottom of the lifter until you
have oil pressure and then it become solid, you should put a 2nd mark on top of rocker so you
know it has been double checked all rockers that are 100 % finished being adjusted you
should have a magic marker X on them one mark for 1st adjustment 2nd mark for final check.



The stud on the champions are suppose to be 75 ft lbs. In a magazine i saw a white thread sealer being used. Im using just a dab of locktite blue. i pulled it off awhile ago with no problems from the previous install. i was adjusting my rockers because of the noise, and stumbled on this post and just went on & decided to change all to ARPs on the driver side . i 'll do the passenger later, my passenger side is as quiet as a flat tappet my drivers a little louder which is what im tryin to rectify now.


Heres the pic for part #ARP 134-7104..


ARP's on the left -----Champions replacement or what i think are (trick flows on the right).



On the bottom pic if you line each top up bolt to bolt the length is very close only like 2 or 3 threads difference.
I wonder if you go lower could some one just use the stock valve covers with a thicker vc gasket like the 1600s and get away with it?? hmmmmmmmmmm?:confused:
 

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The problem with shorter studs, is that you risk not having enough thread engagement in the adjusting nut. Rocker geometry is VERY important. That is worth repeating: Rocker geometry is VERY important. You can free-up or loose a measurable amount of torque output in the engine if the geometry is out of whack. I think you would be better off using longer studs and installing a stud girdle to help prevent stud failure. No one makes a stud girdle, but sounds like someone should. If there is enough intrest, I have a great machinist that could whip some out. Valve covers would have to be fabbed to clear the girdle, though. Not sure there is enough room to fit a super tall valve cover on the passenger side, though. The question I have is, why are you breaking studs? There really isn't alot of spring pressure with a hydraulic roller. Maybe time to step up to 7/16" rockers and studs. How are you determing rocker geometry and pushrod length? It takes time to get things right. Food for thought. Maybe it is just poor material in the studs?
 
I'm hoping it is a combination of cheap studs and overtightning the poly lock set screw. We'll see.:redface:
 
If you look at the pics i took the APR bolt seems to look more finished than the Champion ones........ if anyone has a way of testing them just for ****s and giggles ill send them one champion and one ARP bolt .
 
If you look at the pics i took the APR bolt seems to look more finished than the Champion ones........ if anyone has a way of testing them just for ****s and giggles ill send them one champion and one ARP bolt .

I can when I get the ARPs. I have access to a hardness tester at work.
 
If you look at the pics i took the APR bolt seems to look more finished than the Champion ones........ if anyone has a way of testing them just for ****s and giggles ill send them one champion and one
ARP bolt .



I Agree with you galoush..... hey did you notice the champions you received from tom has 16 threads and the ones i received from tom had 20 threads. but the arps you have have about 20 threads but the one i got have 12??? my locks are screwed on pretty good once i set the set screws on my intake side my set screw only showed like 2 threads deep??????

The problem with shorter studs, is that you risk not having enough thread engagement in the adjusting nut.


Very good point i shouldve known that.


Rocker geometry is VERY important. That is worth repeating: Rocker geometry is VERY important. You can free-up or loose a measurable amount of torque output in the engine if the geometry is out of whack. I think you would be better off using longer studs and installing a stud girdle to help prevent stud failure. No one makes a stud girdle, but sounds like someone should. If there is enough intrest, I have a great machinist that could whip some out. Valve covers would have to be fabbed to clear the girdle, though. Not sure there is enough room to fit a super tall valve cover on the passenger side, though. The question I have is, why are you breaking studs? There really isn't alot of spring pressure with a hydraulic roller. Maybe time to step up to 7/16" rockers and studs. How are you determing rocker geometry and pushrod length? It takes time to get things right. Food for thought. Maybe it is just poor material in the studs?


turbo i dont know if your talking to me or major nutz. but mine only broke once for some reason i ordered 2 spares from tom and received them and put them on soon as i drove down the road the opposite side broke and done the same thing dont know if it was a bad batch or what. no more problems but i was just adjustin a noisy rocker or two & just decided to replace mine since id already bought the arp's i believe my thread coverage is sufficient we'll see i did notice my engine builder installed the rocker pivot center piece upside down the flat piece is suppose to be facing flat side up against the poly lock base now im gonna HAVE to do the other side pretty quick. i bought my heads from tom through full throttle my suggested spring psi was 135 or 140lbs. my pushrods were 8.55 with my 212/212 comp hyd roller. my studs are 7/16" 1.55 ratio rockers.:smile:
 
Had some problems w/ the "Scorpion" rockers. Seems that they were being assembled by Dove, and were fubar in the brg area...
I had several that were locked up, and had to replace the entire set. [Tom replaced them for me.]
If any of the rocker studs that were broken, had locked up rockers on them, the stud will take a hit....
 
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