Grade 8 all thread OK for head studs?

Hey I was just wondering if grade 8 all thread would be suitable for use as head studs for my 51 flathead. Believe its 7/16 threads. May be a dumb question, just didnt know if it would have enough tensile strength. Thanks
Ben

 

Call Flathead Jack and order head bolts. Buy the snake stuff he has to seal it if you dont have access to well water.

 

Studs have coarse threads in the block and fine threads on top with nuts. If you use threaded rod you have coarse threads on both ends. Torque specs for studs assume fine threads. What to use for torque on coarse nuts is now the question; would it be the same as bolts? Maybe, but to be safe I'd say either use real studs or bolts.
I would think grade 8 rod would be strong enough to answer your question. With matching grade 8 nuts.

 

Quality head studs are well worth the investment. ARP and other high tensile studs are roll threaded versus cut threads on all thread. Don't skimp, talk to Flat Head Jack and buy his offering.

 

Also studs will have a short threaded end to fit in the block that will bottom out and prevent them from turning when the nut is tightened. Threaded rod could keep turning as the nut is tightened and go too deep into the block. Not good.

 

The all-thread will have a poor thread class (tolerance of the threads); not a good idea for a head stud. This isn't an item to cheap out on. Pony up and get some legit studs or bolts.

 

No.
No.

 

Uh...no.

 

All thread will have a different stretch than real head bolts. It is the stretch that creates the holding power. you will not get a proper torque reading nor will they clamp the head effectively to the block.
In other words - NO!

 

Thanks for the help, any suggestions for sources? flat head jack has a listed retail price of about $270, that is way out of my price range. may just be sticking the old bolts back in

 

The cheapass in me is grinning like an idiot!

 

If you cant build it right, you better buy a tow truck, cause your gona need it.

 

Grade 8 is alright ,Back in the late 60's early 70's He used socket head cap screws as headbolts ,Otherwise known as allen head bolts. I might do the same . And also that was on a pontiac 421 ,Pontiacs are known for running hot .....

 

Another thing to consider is that all-thread may not be heat treated, quenched, and drawn in the same manner as bolts or studs. It's just best to use what has been properly design for said application. No sense in skimping on critical parts.

 

speedway has a kit too, around $100 I think. should be of OK quality, but with speedway you gets whats yous pays for...

 

I wouldnt buy Flathead Jacks stuff, Ive used his studs on a customers car and broke a few of them...Yes, i used proper torque sequence, and proper sealant, etc... and HELL NO is all thread ok

 

I would say NO, my reasons would be that the studs designed for the application have a shoulder on them (it also seperates the fine thread from the corse thread) that keeps you from going to far into the block & possibly a water jacket & damaging things, this shoulder is important. Also I do not believe you will be able to achieve accurate torque readings w/the all thread as it will continue to run itself into the block in certain instances.
As a money saving tip, the Speedway kit is more than affordable & up to the task. I know because I have used them many times as well as ARP, both get the job done. They are Grade 8 studs, come with all the nuts & washers you need, just make sure you order the correct stud set, order it to match the year of the heads you are using not so much the year of the block (I say this because some folks like to run early style heads on late blocks & the Speedway sets are sold based on the heads).
The sorta odd thing about this is that on certain off-set generator brackets the mounting kit is usually made up of 3 Grade 8 All thread studs, coarse thread. I guess the speed equipment folks feel that 3 out of 24 or 21 won't kill ya!

Well now you have my opinion too, I hope some of this is helpful.

Sincerely,

Cheatercarl

 

Get the lengths that you need and call ARP and buy them. They sell single studs probably in a length real close to your liking. Can also buy individual nuts and washers.

 

No no no. Sorry to finish your sentence man.

 

I have a great who is building a '53 Merc for me and he wants to replace the head bolts with studs (I'm keeping the original heads) I'm fine with that, but wonder about the cost. His supplier charges him around $400.00 and Speedway has a kit for $100.00. I have heard Speedway uses Chinese or Japanese parts in some cases. Could this be the reason for the difference in cost and should I just fork out the extra cash for what sounds like USA studs?

 

I'm happy with the Speedway stud kit.

 

this is flathead stuff we are talking about here right?

unless there is visible stretching or other damage to the originals I would clean them up and reuse them.

damaged ones I'd replace with good used ones salvaged from another motor.

 

Yeah, +1 on that.

Henry's steel was tested by Joe Abbin (google him) and he found them stronger than grade 8. If you have the original bolts, use them and don't worry about it.

I admit I am using studs, but they aren't necessary and I am using them because I want to, not because I have to. They worked for how many years since old Mr. Ford had them put in your motor?

 

I have to add another no. for the same reasons given. Do some hunting and searching and you should be able to find a set of real head studs for not much more than the cost of what the grade 8 all thread would be.

The thing about a lot of head studs and or head bolts is that the shank is a specific diameter and not the same as an over the counter bolt or stud. On engines without dowel pins that helps locate the head exactly where it should be.

Sometimes we just have to bite the bullet and rathole cash for a couple of more paydays and buy the right stuff. It beats sitting on the side of the road with a steaming flathead and wondering where the hell you put Hotrodlaydycruiser's cell phone number so she can post another "rodder busted down on the side of the road" thread.

 

IIRC SHCS (Socket head Cap Screws well at least the good ones) have a rating that states "exceeds grade 8" and are typically rated at 180,000 psi where a grade 8 screw is normally rated at 150,000 psi.

 

MAC's Antique Auto Parts in Lockport,NY has them at 91.00 per set for 24 stud engine.
http://www.macsautoparts.com/online_ordering.html

 

What made you decide to use studs? Unless your building a "race horse" flatty I prefer bolts.

 

I used all thread for a lot of small stuff but the threads are inconsistent and is the rod is not streight and torque is never rite.

 

if you're down on the bucks, i also would say go with bolts. by the way, speedway also lists the arp stud set for $470-$480, depending on the brand of head.

 

I'm gonna guess that by now , 4 yrs as passed, that he's got it figured out no?
And using all thread for head studs is pretty damn silly anyway.