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I’ve never run aluminum heads on an engine before.
I’m getting ready to bolt the new headers up to my new aluminum heads and was wondering which is better, header bolts or header studs?
Can there be interference issues when using studs?
My thoughts are that bolts are better, but I am a little worried about having to remove the bolts in the future.
I always use anti seize when installing bolts into an aluminum part.
Should I use standard anti seize on header bolts or is there something better because of the high heat?
Thanks!
Studs are always better...in just about any application.....
I use stainless ARP everything and never use anti-seize on fasteners that are captured by a gasket.....and with a lot of heat surrounding it there is nothing to react.....especially with the stainless......
Now we will probably get some "dissimilar metals" guy on here to comment but I personally have never seen electrolysis on components that are clean and dry.......
Using anti-seize on header bolts to me is counterproductive as they will just come loose easier......studs usually stay tight......
They do make header gasket changes a PITA......as the whole header has to come off unless you remove the studs from the head......
There used to be a Copper Anti-Sieze....but it has been discontinued.....they say just to use the regular....
I could only find stainless ARP studs in 3/8". Were I to do it over, I'd insist on 3/8" thread into the block, and 5/16" thread (and nuts) to mount the headers. I got them mounted, but they were a tight fit for the wrench.
I'm using ARP 12 point stainless steel bolts on my BB with Hookers. Cylinder heads are aluminium. Access to conventional header bolt heads can really be an issue unless they have reduced or 12 point heads.
I use copper anti seize both on the the stainless header bolts and spark plug threads. Thread precision of tapped threads in the Brodix heads is generally 'tight' with both plugs and bolts needing a bit of help when removing where there is limited access.
I use flat (not spring) washers. In 15 years none have ever loosened-off.......the reason why? - most manufacturer and 'off the shelf' header bolts are IMHO supplied too short. I simply measure depth of all tapped header fixings. Using a set off over-length bolts have them turned-down to the shortest measured length of tapped hole. Result - no bottomed-out bolts and no self-loosening bolts. The 12 point headed bolts give the option of socket and/or ring spanner use where access is limited.
You don't put stage 8 bolts or any bolt into aluminum heads.
use felpro blue steel header gaskets ans just dab some high temp red silicone to the top i've never had a bolt back off. I use red lock tight on the studs.
So is this the correct recommended ARP Stud kit for a BBC? BBC Stud kit
It looks to have 38/" coarse thread studs with the smaller 5/16" fine thread 12 pt nuts on top. Takes 7/16" 12 pt socket vs 9/16" hex.
I love Gkulls idea of a dab of silicone for an anti-vibration locking effect! Genius.
I don't do 12 points unless your primary pipes are designed to be able to get a 12 point socket on them. Which is not the case with 1 3/4 inch SBC. I'm not sure about the posters BBC headers. If the pipes are big you can't even rotate 12 point flare nut wrenches. my head studs are 12 point so the smaller socket will clear the valve springs.
Summit has the vendor catologs which show more stuff than on line, or you can call ARP and get the part number to order from summit. But I use the little 5/16th hex nuts black oxide. 3/8ths hex are so big that they don't clear my pipes.
Reusing a felpro blue steel header gasket from the motor I pulled out. You can see red locktight running down the head. The nuts are shouldered is another reason for doing the smaller nuts. SBC exhaust studs are right next to the port on bigger CC aftermarket heads.
Looks like I had to beat the solid engine mount to get it on the frame. They get crushed in from the previouse engine
The 5/16th is even too big for some of my tubes and I had machine off the shoulders for a couple of cylinders. Spin them in a lathe
I get what you are saying. The 12 pt design prevents you from using an open head wrench if needed.
But the only other ARP BBC stud kit I can find, with hex nuts, uses the much larger 9/16" hex nuts, and is 3/8" bolt thread on both sides. Although I believe the nut side may be fine thread,
I do not see a version with the 5/16" nut thread, that also has the smaller hex nuts.
Maybe that version is only offered for SBC and not BBC?
Actually I do not see that listed by ARP at all.
Did you do something custom? Or order the small hex nuts separate?
I get what you are saying. The 12 pt design prevents you from using an open head wrench if needed.
But the only other ARP BBC stud kit I can find, with hex nuts, uses the much larger 9/16" hex nuts, and is 3/8" bolt thread on both sides. Although I believe the nut side may be fine thread,
I do not see a version with the 5/16" nut thread, that also has the smaller hex nuts.
Maybe that version is only offered for SBC and not BBC?
Actually I do not see that listed by ARP at all.
Did you do something custom?
That is why I said to call. Summit has Vendor parts books that the tech guys can look through or call ARP
Hey Everyone,
Thanks for all the feedback.
I talked with the engine builder yesterday afternoon and he agreed with you about benefits of using studs.
His comment was “if I can”.
He told me that every head and header combination is different and using studs on big blocks can be a challenge.
I will be running Hedman 2” primary tubes on Edelbrock Performer RPM heads and the builder said to try them if I want but in his experience I won’t have the clearance to install some of the nuts, and if I need to remove the headers, having studs may cause interference issues on a big block Corvette.
He also suggested using 1” bolts because getting full engagement in the heads is the key to keeping the from loosening.
I ordered a set of 1” ARP hex head header bolts and plan to use anti seize.
On my boats and other cars, I’ve used socket head bolts when I’ve run into clearance issues with headers.
They always solve the problem with interference and I’ve never had any problems getting an Allen wrench in to tighten them down.
I have a few Allen wrenches I’ve shortened just so they align with the socket heads and the ones with the ball ends are life savers.
If the ARP’s have any issues I’ll just use socket heads again.
The Nord Locks shown above are great and I’ve used them in some of my suspension compartments.
What your engine builder was talking about for BBC is that you can't just install all the studs and then fit the headers over them like a SBC.
What we have had to do is to put one or two studs on the front cylinders. Then the gasket and headers. Then through the header flanges holes run the studs in. studs only go in finger tight. I've also double nutted them to get them snug. The whole Idea of a stud is that it doesn't hurt the threads and pull on all of them equally
The main reason studs are better is because when you use bolts, both the pulling/clamping force as well as the friction are being applied to the weaker aluminum material threads. When you use a stud, you thread it in under no load, and the mating threads become “static”. Now when you put your nut on the stud, the clamping force and friction are applied to the much stronger stud threads. This is the reason why thread repair inserts work and are stronger than base material threads.
It’s true, factories do use bolts into aluminum heads, but they are only meant to go in ONCE, under precise torque control, and they can survive that. When you start removing and reinstalling bolts in aluminum heads is when things go bad. (I’m looking at you, Ford F-150 triton exhaust manifolds. I went thru that BS once and never again.)
Only way I’d put bolts into aluminum heads is if I would first drill and tap a thread insert.
02-15-2024, 02:04 PM
Header Bolts or Studs?
