Head Studs or bolts, which is better ?

Ralph Moore

Ralph Moore

Well-known member
Kinda wondered , does it make a difference? Are pre 49 engines required to have studs or are they interchangeable ?
 
head studs are much better for some softer metals, such as cast iron and aluminum ,these metals wont take much twisting torque when tightening, the threads will be stripped or pulled out, its best to use these with nuts because the torque is applied in a straight line with out being screwed in, and yes bolts can be used in place of studs but not a good idea
 
So studs in place of bolts is better?
I always see hi performance " drag racing" engines with studs. But all modern manufacturing has gone to bolts. Just cheaper I guess.
 
I worded it wrong, studs for soft metal, so the threads wont be ruined because of twisting while torqueing, bolts for harder metals, all aluminum blocks use studs, I don't like studs because they make head removal very hard. and knowing how henry thought, bolts are cheaper, no nut and bolt only has to be threaded on one end, saves time and parts
 
WestCoast said:
head studs are much better for some softer metals, such as cast iron and aluminum ,these metals wont take much twisting torque when tightening, the threads will be stripped or pulled out, its best to use these with nuts because the torque is applied in a straight line with out being screwed in, and yes bolts can be used in place of studs but not a good idea
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I guess that is why all small block Chevy have studs?
 
IMHO Studs are the right way to go for a flathead. Ford used studs because of the ability to tighten the heads properly. The coarse threads will not allow the proper torque as a fine thread will. That's why studs have a fine end and a coarse end. A stud will not "bottom out" in the block as a bolt can (the coarse threads are too short) and leave the head "loose". The studs are designed to tighten into the block(coarse end) and then allow the nut to tighten down the head( that's why the fine threads extend well into the head). I know many engines use head bolts however this is the explanation I was given several times when the topic came up about Ford Blocks/heads/studs vs. bolts
 
I never use studs, over kill. I only torque to 45 ft lbs for 3 heat cycles. Back in the day when racing I used studs because they are better,but having to remove the heads very often made them a pain in the a**. After realizing that having 24 stud/bolts torqued to 50 Ft Lbs was more clamping force than a blown Hemi on nitro. I figgered the bolts were good enough. Even grade #5 will do the job??
 
I just got done putting the heads back on a motor and had the same dilemma. I went with the studs but after I got it done think I should have gone with bolts. I had used bolts on a different motor before and they worked fine. My concern with the studs is to get the heads back off again. Was told no problem but we will see. For the next build, I will side with Ol'Ron's experience.

Neal
 
32phil said:
IMHO Studs are the right way to go for a flathead. Ford used studs because of the ability to tighten the heads properly. The coarse threads will not allow the proper torque as a fine thread will. That's why studs have a fine end and a coarse end. A stud will not "bottom out" in the block as a bolt can (the coarse threads are too short) and leave the head "loose". The studs are designed to tighten into the block(coarse end) and then allow the nut to tighten down the head( that's why the fine threads extend well into the head). I know many engines use head bolts however this is the explanation I was given several times when the topic came up about Ford Blocks/heads/studs vs. bolts
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Exactly, excellent answer. No need to beat this thing any farther. Regarding removing the heads if using studs, I've found the reason it's sometimes difficult to pull the loose head up off the engine is due to the studs not being screwed in straight and are thus binding on the walls of the holes in the head. I've found a remedy. First, identify the problem studs. Then, on each guilty stud, replace the nut a few turns and "center" the stud in the hole with a whack or two from a hammer. Now the studs will not bind in the holes (or is it the other way around?) and the head will come off very easily. Juice it up with a squirt of WD40 in each hole for good measure.
 
ford used studs to 1948 then went to bolts in 1949 whitch was still a flathead . what more proof do you need that using bolts to replace studs is not a proulbem
 
Studs are way better, more trouble but way better. Anybody that stears you toward bolts is lazy thats the only good explanation. On my aluminum heads (Sharp) I open the bolt holes up .015 with a step drill. I raced blown hemi's and chebby's for 30 years and a nitro hemi for 6 years and never had a head gasket problem...never! All with studs. My flatties are leak tight. I use aviation Permetex on the coarse end of the stud and screw them in by hand, double nut and lightly torque with a hand wrench, I use a little white lube on the fine end and high quality nuts and washers, Torque to 55 to 60 pounds is steps. Re-torque as often as they move.
 
There is no difference between the clamping force available with bolts or studs. If frequent removal or alignment characteristics or speed of assembly are factors then studs can have an advantage. For easier head removal, surface cleaning, or ease of replacement, bolts hold an advantage. In most examples the heads are installed and remain in position for years so there is no wearing of the thread surfaces and bolts work just fine. In a competition engine where the heads are removed at least once per week, and sometimes several times per week, studs should be considered.
 
El Rat said:
Studs are way better, more trouble but way better. Anybody that stears you toward bolts is lazy thats the only good explanation. On my aluminum heads (Sharp) I open the bolt holes up .015 with a step drill. I raced blown hemi's and chebby's for 30 years and a nitro hemi for 6 years and never had a head gasket problem...never! All with studs. My flatties are leak tight. I use aviation Permetex on the coarse end of the stud and screw them in by hand, double nut and lightly torque with a hand wrench, I use a little white lube on the fine end and high quality nuts and washers, Torque to 55 to 60 pounds is steps. Re-torque as often as they move.
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I agree 100%. The change to bolts was a cost reduction by FoMoCo, both in manufacturing and in service. Many things changed at Ford after Henry passed away, and many were not for the better. I am convinced that anyone who was rebuilding these earlier engines (pre 8ba) with bolts did it because it was quicker, easier, and cheaper for them, not because they felt it was better. Overkill, I am sorry Ol Ron, I cannot agree with you on that one!
 
And, just to muddy this up, there are the 'combination' guys that have posted a few times.
Maybe two, or four studs, to help assembly alignment, and the rest, bolts.
Still leaves the heads relatively easy to get off.
 
I would think the fine threads on the studs give you a better, even torque. Ford went to bolts to make it cheaper to build, not better. Most changes were for this reason
 
This is one area of the build we allow the customer to make the call, after we've explained the "pro's & con's" of either/or.

We feel it doesn't matter all that much, both work! Bolt's, relatively speaking are usually less costly!

Thanks, Gary in N.Y.

P.S. Whichever fastener type you choose I would recommend NOT installing any anti-freeze until everything has had time to seal up. Even "minute" leaks seal up quicker with fresh water. Just be careful of outside temps??
 
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