Couple Questions Regarding Head Stud Fitment

Shoebox

Shoebox

Well-known member
So I'm doing a trial fitment of the ARP cyl. studs on my 8ba build. I always thought that all head studs went into water in these blocks. On this block at least, 2 holes are not. Two are closed end and those studs stop short by about 2 threads from bottoming (see pics, flagged by masking tape), should I shorten those studs so the shank bottoms on deck?


Second sorta related question, one stud hole which is through into water has a bump out of the casting, just beyond the internal threads which limits the amount the stud can thread in by about 3/16" (see 3rd pic), I imagine I need to shorten that stud enough for the stud shank to bottom out, yes?


Really appreciate all advice & comments,....thanks guys.
 

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If a stud is bottoming out and you still have threads showing, then cut/shorten the threads so it doesn't bottom out.
 
46 of the 48 studs go clean through to the coolant, there are two of them that do not. Those will be the two of them that are not leaking. I ran a tap into every stud hole to clean the threads. Sealed the threads and screwed them in. Started it up and a bunch of them (except those two) were seeping coolant. I was wondering how was it that new Ford engines did not leak. I read up on them and apparently, they used an interference fit on the stud's threads to make the seal. So, I'm no longer running a tap into head stud holes in the block, just cleaning them really good. Just in case the interference fit story is true and there were special threads to make the seal. The leaking studs I had were sealed with Permatex that did not work. So cleaned them up and sealed them with the low-grade Loctite and let it dry for a couple days before I put the heads on, problem solved.
 
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That one by cyl 4 is sticking out a long way. Are the coarse threads on the ARP studs very long? That hole ought to be at least as deep as the other blind hole. If shallower it might need some attention. I don't have access at the moment but someone ought to be able to say the thread length on a 59A stud. That might serve as a guide.
If the threads are over long it might cause issues on a later stud removal job.
Mart.
 
I read the interference fit thread story too, so I used a couple of stiff wire tube brushes on a drill to clean up the threads.

Still leak.

Heh, maybe the guy before me used a tap?
 
I use a stock Ford head bolt, cleaned up and with grooves cut in it as a block thread chaser. I have had minimum problems with leaks, solved by the application of block sealer.
 
So far I've been lucky never had coolant come out around a head stud or bolt(8ba's have bolts) so I must bedoing something right. Even the 292 V12 was dry . I use the white permatex pipe thread sealer. Tim
 
Mart said:
That one by cyl 4 is sticking out a long way. Are the coarse threads on the ARP studs very long? That hole ought to be at least as deep as the other blind hole. If shallower it might need some attention. I don't have access at the moment but someone ought to be able to say the thread length on a 59A stud. That might serve as a guide.
If the threads are over long it might cause issues on a later stud removal job.
Mart.
Click to expand...


"Second sorta related question, one stud hole which is through into water has a bump out of the casting, just beyond the internal threads which limits the amount the stud can thread in by about 3/16" (see 3rd pic), I imagine I need to shorten that stud enough for the stud shank to bottom out"
 
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I just installed some Edelbrock heads. Previously I've used ARP thread sealer and had leakers. This go around I used Hercules Steam Pipe sealer I got from a HVAC jobber. Worked great and not a drop of water.
 
Two cents worth: I always use a thread restorer kit to clean up threads rather than a tap and die. Taps and dies are more aggressive. Didn't expect it when I bought it but the thread restorer kit is one of my favorite and more frequently used tools. Here's an example of one. Mine's a Craftsman but it looks identical; likely came out of the same factory. I have a tap and die set too but seldom use it.
 
SoCalCoupe said:
Two cents worth: I always use a thread restorer kit to clean up threads rather than a tap and die. Taps and dies are more aggressive. Didn't expect it when I bought it but the thread restorer kit is one of my favorite and more frequently used tools. Here's an example of one. Mine's a Craftsman but it looks identical; likely came out of the same factory. I have a tap and die set too but seldom use it.
Click to expand...

Same here. I use mine all the time. Essential tool for sure.

I forgot the manufacture's name, but they made them for Snap-On, MAC, Craftsman, etc. They are all the same.
 
I have a thread restorer kit too, but I still use a modified Ford head bolt to chase the threads in the block. I don't know a lot about thread types, but I do know there are three or four different types, and the only one I can be sure is correct is a genuine Ford bolt.
 
Just to add some background to my current build, I learned of the recommended use of a thread chase/restorer, not a tap, here on The Barn. Prior to sending the block off to the machine shop, I chased(not with a tap) all threaded holes. In the past I used ARP thread sealer and had no leaks,am planning on using again however, I did pick up a product that some here highly praised, Leak Lock, .....so now a bit on the fence as to what to use.


The other issue I brought up, that the two studs that go into the blind holes, bottom out with 2 threads showing. Recommendation is to trim stud, which I can. Question is considering holes are blind, does it matter? Thanks.
 
The fact the holes are blind - means it really doesn't matter, but I like to shorten the threads to ensure that the stud can't get overly tight and crack the casting at the bottom. It is just insurance - for peace of mind!
 
Hmmm, good point, shorten it is.


My Dad always said, "The dumbest question is the one you don't ask"
 
During the era that studs were common, there were oversized studs available. The sizes varied but most would be from .003" to .005" oversize. Those days are long gone. Most mechanics I recall used aircraft Permatex sealer on the threads before installation. This would seal and reduce corrosion over long periods of service.
 
This has been drafted awhile ( never posted ) this thread seems a good of place as any to place to tack it on to.

I puchased my Offy 400 heads , stud set , hardened washers, & nuts in 2018 from Speedway Motors . Around 6 months ago I started to hang it all together , it turned out the studs were all about .120 “ short resulting not getting a full nut of thread. It was going to be messy complaining so I decided to recess the hardened steel washers into the heads 120”, with that out of ther way I used Permatex # 3 on the coarse threads to the block, using the 2 nut setup to seat in the block , a quick try of the head going on, no way, proceeded to check studs as per. ( Photo 1 & 2 at 12 and 3 o`clock . ) Three or four of the studs needed help with a suitable sized hammer to help them stand up straight , suitable anti seize on the stud shanks and the heads went on fairly easy. On to the next problem , some where between 40- 45 ft. Ib on the torque wrench I pulled 3 studs on one bank 2 on the other ( torque wrench checked out ok ) off came the heads , I decided to stress test all the studs using a suitable sleeve to 55 ft-lb found another 4 dodgy ones , having no other viable option I drilled out a spare cast iron head as a tapping quide for 1/2” UNC , prior to tapping I machined a drill guide 1/2” od for the tapping drill size. ( Photo 3 )

Sourcing some Grade 8 1/2 “ bolts I machined and threaded the upper part for 7/16 UNF ( photo 4 ) the small collar ,100 “ high was recessed into the head surface and a Dremel eased the gasket hole as needed.

Thinking over my problem, I feel I might of left the block in the molasses tank too long and the threads not being protected by the studs and being a small surface area were compromised by the acidity in the molasses, also is the possibility that the rust build up on the bottom of the studs did some damage on removal. The fact that I used a 7/16 HT head bolt with grooves cut along it as a chaser might not of helped. It was a GM bolt, maybe sabotage.

I made the mistake of following Offenhausers recommendation of silver paint on the composite gasket , removal within an hour, no problem , after 4 months real pain in the rear end. Next install dry ! Ah, the fun of it all.
 

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Shoebox
I am the one that started the thread (NO pun intended) on "LeakLock". It is sort of the same industry/application as Tim has described with his "new" product over the ARP stuff, My local flathead builder/guru has been using it for over 6 years now on all of his builds (all high end built engines) and had not had ONE issue with any leakage when applied correctly!!! Again, he learned of the product working for the Navy here at the local Nuke Sub base on some high end compressor cylinders and connections where it was "spec's" by the manufacturer for the Navy!!


LeakLock https://www.highsidechem.com/product/leak-lock-pipe-joint-sealant/
 
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