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Old 07-11-2019, 12:30 AM   #1
1ton
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Default New head studs or no

Getting ready to tear down my late 31 four banger. My question to you guys is this. Should I plan on reusing the original head studs or not? They are coming out easy. On newer engines they always recommend that the head bolts or studs get replaced with new. What say you?
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Old 07-11-2019, 06:42 AM   #2
Ray64
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Default Re: New head studs or no

I would if they are comming out easy
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Old 07-11-2019, 07:36 AM   #3
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Default Re: New head studs or no

The only thing you risk is possibly breaking one on install/torquing. And having to start all over.

If you get it in and torqued, its probably good for the life of the head gasket. Maybe longer.

The most severe force a fastener sees in its life is the initial torquing - that if its done right. Thermal cycling is recommended (each cycle measurably relieves the stress) so you're essentially "re-torquing" to bring the initial stretch back. If it survives that, then its good.

Again, if it survives...

Note that new fasteners CAN fail - although the failure rate is significantly lower.

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Old 07-11-2019, 07:42 AM   #4
bigd1101
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Default Re: New head studs or no

Bolts are cheap........go new.
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Old 07-11-2019, 07:44 AM   #5
gary678*
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Default Re: New head studs or no

Use new grade 8 studs (stronger). Extra cost is minimal and will serve as a cheap insurance policy.
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Old 07-11-2019, 08:41 AM   #6
alexiskai
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Default Re: New head studs or no

The cost for new nuts and studs is about $30 shipped, so it depends whether that feels like a lot of money.

The other thing to consider is that, if you use all new studs and nuts, you can be pretty sure that they'll all respond the same way – in other words, applying X ft-lbs of torque on the #1 nut will place exactly the same amount of compression on the head and head gasket as putting that torque on the #2 nut, the #10 nut, etc. If you're re-using studs that have been in the engine for decades, the consistency of the force will be decreased due to varying levels of metal fatigue, etc.
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Old 07-11-2019, 07:16 PM   #7
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Default Re: New head studs or no

It is not just a question if the original studs can be reused, the better quality studs will perform better. The original studs are soft and over time will stretch. If the head nuts were not periodically re torqued, head gasket failure could occur.


With better quality nuts and studs, the nuts will hold their torque a lot better resulting in less chance of head gasket failure.


I always recommend replacing the studs and nuts especially if you will be using a higher compression head where you really need to increase the torque on the head nuts.


My recommendations,


Chris W.
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Old 07-11-2019, 07:49 PM   #8
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Default Re: New head studs or no

BUT, & WHY ?? Are the new style studs shape NOT the same as the Originals ? The Originals have a larger/thick area in width just where the head hits the block area, the re-pops are the same size top to bottom.. Is this just another, Its a Reproduction, did you expect any more ??.
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Old 07-11-2019, 08:21 PM   #9
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Default Re: New head studs or no

New studs are more consistent in material and formation. Plus they don't have any issue yet with corrosion - which can be a fail point. Dimensionally they are identical with old.

For the common run of the mill Model A with an original head I would re-use studs. In my most recent learning curve using a dedicated "stud puller," before the puller I ruined 2 out of 4 studs being removed. The ruination had to do with the threads trying to use the "two nut" method. After the puller - none - and all these will be re-used. I have a box full of studs from the last motor I went through and saved a majority of studs so I guess I have a complete set of used.

As to stretch - new or old stretch about the same. Modulus for steel is modulus for steel, at least until you get to things like lathe boring bars made specifically for rigidity. As to grade numbers, I would put old studs as "augmented grade 5." Grade 8 new would be stronger - but its a strength you will never use. You will pull out of the block before these break.

And there is some danger in that.

Were I to plan to go above the 55 ft-lbs of normal application I would probably use new Grade 8. As it was on the last motor I did go new grade whatever (not 8) from the supplier. But I have a standard head.

And someone said something about not having to re-torque new studs? Um, most if not all of the re-torque requirement comes from compression and thermal set of the gasket. And this won't change no matter the studs you use.

But do as you will - and by all means please report back your experience.

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Old 07-11-2019, 09:41 PM   #10
Gary WA
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Default Re: New head studs or no

use some anti-seize on threads to block. new studs for sure.
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Old 07-11-2019, 10:00 PM   #11
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Default Re: New head studs or no

don't look back new studs
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Old 07-11-2019, 11:53 PM   #12
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Default Re: New head studs or no

The only disadvantage I see with using new good quality studs is the cost of the studs.


I see many disadvantages too using old studs, many of which have been previously discussed. With old studs, you do not know if there are any cracks that are starting to develop, you do not know if they have been over torqued by some previous "mechanic", often there is a necked down area from corrosion that is prone to failure and on and on.


You can definitely feel the difference when torqueing a head, or anything else for that matter when you are using fasteners made from better materials than the materials that were commonly used at the time our cars were built. It costs a lot of money and time to build a good Model A engine and personally, I see no reason to take a chance with old studs or any highly stressed fastener in the engine.


HOWEVER, I am definitely sure that others will have a different opinion and that is fine with me.


We all must do what seems to yield the results we are looking for.


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Old 07-12-2019, 02:18 PM   #13
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Default Re: New head studs or no

Recently changed out all mine for chrome moly grade 8 studs. A little anti- seize on them. Just remember that the #8 stud is a bit longer than the rest of the short ones. That is for the ignition cable clamp, which a lot of us don't use. Of course the two water outlet ones are much longer.
A cheap precaution while you got it apart. Enjoy the adventure... Chap
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Old 07-12-2019, 04:50 PM   #14
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Default Re: New head studs or no

Grade 8 studs also have a closer tolerance thread fit to the block. That is why I use them.


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Old 07-12-2019, 08:58 PM   #15
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Default Re: New head studs or no

I had to pull my Model A head to fix some burnt valves. I lapped in the new valves and I am ready to start putting it back together. I am running an original head at standard compression and I was planning to use the current head bolts because they don't look bad and the threads are good. The cost of new head bolts is not holding me back....I just don't like the thought of breaking a head bolt off in the head and having to drill it out. If I get a head bolt tool to back them out, how likely am I to break a head bolt getting them out??
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Old 07-12-2019, 09:19 PM   #16
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Default Re: New head studs or no

If you buy the Ares tool, you won't break any. Works best with a 3/8" impact wrench.

https://www.amazon.com/ARES-70016-Da...s%2C190&sr=8-6

2 day delivery for me from Amazon.

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Old 07-12-2019, 09:43 PM   #17
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Default Re: New head studs or no

Quote:
Originally Posted by bdtutton View Post
I had to pull my Model A head to fix some burnt valves. I lapped in the new valves and I am ready to start putting it back together. I am running an original head at standard compression and I was planning to use the current head bolts because they don't look bad and the threads are good. The cost of new head bolts is not holding me back....I just don't like the thought of breaking a head bolt off in the head and having to drill it out. If I get a head bolt tool to back them out, how likely am I to break a head bolt getting them out??

In this case, I would go ahead and stay with the original studs.


If you have the engine out at some later date for a rebuild, that is the time you may want to consider upgrading the studs.


My opinion,


Chris W.
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Old 07-13-2019, 10:33 AM   #18
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Default Re: New head studs or no

Any body ever replace the studs with cap screws, like they used on the model Ts and the later flathead V-8s and modern engines?
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Old 07-14-2019, 07:21 AM   #19
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Default Re: New head studs or no

I got one of those Ares tools from Amazon and it worked great. I was blessed that the old studs came loose with just a little nudge with a 24" breaker bar. One hand pulling on the end of the breaker bar and as a precaution the other hand holding the bar steady right over the stud. I didn't want to have it angle and snap a stud... The tool sets down on the stud pretty deep and helps avoid any angle.... Enjoy the adventure... Chap
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