FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: gregaba on December 29, 2021, 05:54:31 PM
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I was reading an older artical by Motor trend today that said when you install the rocker studs to bottom them out and then back them off a couple turns or they tended to pull the threads out of the head when you adjested the valve's.
Never heard of this. Anyone had this problem?
Thanks
Greg
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Just turn the page! ;)
Scott.
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Free advice. I have Edelbrocks. They use a nasty little thing called a Helicoil. I bought the ARP stud kit from Precision Oil Pumps. The studs tighten up with an allen wrench. I double nutted the 3/8-24 stud and torqued them to 45 ft lb. I installed the rocker shaft assembly and torqued to 55FTLB per ARP instruction with the lubricant. It pulled three of the helicoils out of the heads. I spoke to a couple others who said to simplt use the T-handle allen and tighten them hand tight.
Also be VERY careful when tightening down the shaft assembly. Do it evenly if there is load on the pushrods.
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Drop a small bearing in and run the stud down hand tight. 🙄 lol
400lb or more of open pressure then yank the helicoils out and use some good T certs or something comparable.
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A couple turns seems excessive, don't recall what instructions say but I just backed mine out a 1/2 turn before torquing.
I think there are a couple reasons to do this, likely more I can not think of, none of which justifies 2 turns out.
Disimilar metal expansion, if stud is bottomed the system is over-constrained and heat will cause something to give
If the stud turns in while torquing you could jack the helicoil out, not knowing what load you are applying, of course it should not move anyways if everything is lubed well
Just a couple guesses
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The Edelbrock FE heads I had, had rocker bolt holes that were quite shallow, I have to think if you were to back the studs out 2 full turns, there would not be sufficient thread depth left. I typically install the rocker studs all the way in by hand, and just back them out, maybe 1/4 turn, maximum.
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If the ARP studs get installed by hand to the bottom loosely won’t they “find their way” through the torque cycle? ( 50 ft lbs).
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Thanks for the answers and commets.
I will just try installing them with a 1/4 turn loose and if they pull out the helicoils I will install Tserts in their place.
At least I have a lot of experence with them due to the 4 4.6's I used to own.
Greg
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My suggestion is, to see how many actual Helicoil threads there are, since the hole will be deeper than the Helicoil, itself.
It may be that the two turns out, is where the bottom of the coil actually is.
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Thanks for the suggestion.
I just checked and found a surprise.
The pervious owner all ready has installed t sert's in them.
I feel like an idiot, I guess I will have to look more closely at my stuff before posting a question.
Anyway I hope it helps someone else that may have the same question.
Greg
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I spoke to a couple others who said to simplt use the T-handle allen and tighten them hand tight.
Also be VERY careful when tightening down the shaft assembly. Do it evenly if there is load on the pushrods.
This would be a fine process. :)
Drop a small bearing in and run the stud down hand tight.
This is technically a correct procedure if the stud fastener does not exhibit an unthreaded nub on the end intended to embed in the bottom on the blind hole, as it is less than ideal to have the first thread on the fastener crowding the unthreaded stud hole at the bottom; and this also works fine if one wants to control the depth of the stud to something other than the hole depth as received; as in the stud is too short otherwise. :)
I double nutted the 3/8-24 stud and torqued them to 45 ft lb. I installed the rocker shaft assembly and torqued to 55FTLB per ARP instruction with the lubricant. It pulled three of the helicoils out of the heads.
So the 3/8" x 16t torque specification in the cylinder head is 45 ft.lbs. but then one stacks the rocker stand (w/ shaft) seated to the head surface and then on the same stud fastener (other end) draws a greater 55 ft.lbs. on a 3/8" x 24t (lower pitch angle)? ??? You just created a great thread puller,.............. oops! :o
Scott.
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I know on my ARP main cap studs, the instructions say to install the studs finger tight only, and also, if using Loctite, on the block threads, to torque the main cap nuts to spec, before the thread locker has a chance to set. I suppose the threads in the block have enough clearance , that if the Loctite fully set, and you then tightened the caps and nuts, the studs threads could move ever so slightly towards to cap and nuts, to break the bond of the locking compound. As for the rocker studs turning and tightening up when tightening the nuts, I have not experienced that, the fine threads are smooth enough when oiled, that the studs tend to stay put.
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................... if using Loctite, on the block threads, to torque the main cap nuts to spec, before the thread locker has a chance to set. I suppose the threads in the block have enough clearance , that if the Loctite fully set, and you then tightened the caps and nuts, the studs threads could move ever so slightly towards to cap and nuts, to break the bond of the locking compound.
The male threads of the fastener need to be loaded against the metal female threading of the casting as if the locking compound separates the two under the no-load installation process and then loaded thru the torquing the locking compound will migrate from between the two leading to loss of the intended clamp-load. ;)
I see little need or benefit in the use of 'thread-lockers' except where one is concerned with the difficulties that might be incurred if at disassembly the stud should screw-out versus just the nut; and definitely not to be used when inserts are involved! :)
Scott.
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The ARP studs that were supplied from Precision Oil Pumps didn't bottom. I did think to check that. If anyone tells you ARP always gives the best advice with their fasteners I have news for you...
Anyway, Time serts were installed in the place of the helicoils. I don't think this will be an issue in the future.
I have about 335 over the nose. That shouldn't have been an issue with the Edelbrocks. I dumped their roller cam springs and went with what was suggested by the cam manufacturer.
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I dumped their roller cam springs and went with what was suggested by the cam manufacturer.
Just note of caution, that unless you supplied the valve springs' 'Installed Height', as accurately measured on your heads, with all remaining valvetrain components intended to be utilized, with understood dimensional values of these for proper relationships of fitment, then understand that the manufacturer may have made a 'suggestion' but it is the 'responsibility' of the installer to establish that such is correct. :-\
In others words: just because someone says something will work, best not to 'assume' that they are correct! ::)
Scott.
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i bet many of us have eaten work because we "assumed" information provided was correct. The springs were installed before the heads went on the car with the custom cam grinder's specification and installed height.