Head Studs

[Matt Wilson]

For those of you running head studs, how do you manage to connect accessories (such as horn), throttle linkage, etc., on your studs?

 

The reason I ask is because ARP studs (which is what most people seem to be using) have threaded sections that are only 1" long, according to two different ARP reps I've spoken to.  That makes it difficult to install nuts for holding the head in place and then having enough thread length remaining above the nuts to install accessories and such.  I think I might be able to find a combination of nut thickness, washer thickness, etc., so that I'll have enough thread to do this, but it'll be awfully close, and if the studs turn at all during nut installation, then it may mess up the whole spacing of everything.

 

The biggest reason I really want to use studs is because I'm going to install dual carbs and having an array of studs will make it easier to figure out throttle linkage mounting arrangements after assembling the engine and installing in the vehicle.  Also, one never knows when I might want to add an accessory at some point in the future, such as power steering or air conditioning....or who knows what.

 

I suppose another question is whether the threaded sections of the ARP studs are actually a bit longer than 1".  If they were just a little longer (even 1/16 or 1/8" ), then that would make a big difference.  Probably wishful thinking, but if they were nominally 1" long, but in actuality a little longer, it would be helpful to know that.  I wonder if someone can tell me if this is the case?

Edited February 15, 2022 by Matt Wilson

[martybose]

ARP doesn't have a kit for our flatheads, you have to order the studs, washers and nuts individually.  So when I ordered mine I ordered two of the studs one inch longer, then made a bridge between two studs to mount the throttle linkage pivot on.  I used a pair of spacers of the right ID and 3/4" long, and welded a steel strap to the top of them in adjacent stud locations, then put the pivot on the strap.

[Matt Wilson]

Thanks, Marty.  I don't quite visualize every detail of your setup, but I get the basic idea, I think.  I still think there's barely enough room for the head nut, a bracket and another nut and a possibly a washer under that second nut, when the upper threaded end of the stud is only 1".

Edited February 16, 2022 by Matt Wilson

[martybose]

You're visualizing it wrong.  With the head on I put a washer, the spacer bridge, then another washer and the nut on top.  The spacer was a very thick wall steel, maybe 1/4" thick, so there was no problem with torquing that nut on top of the spacer.  Don't forget that because the top of the studs are fine thread, you don't torque them as tight as bolts.  If memory serves the OEM bolts are 75 lb/ft, while the stud nuts are only 55.

[Sniper]

I got a couple of Milodon studs that are longer and may be the ticket.

[Matt Wilson]

37 minutes ago, martybose said:

You're visualizing it wrong.  With the head on I put a washer, the spacer bridge, then another washer and the nut on top.  The spacer was a very thick wall steel, maybe 1/4" thick, so there was no problem with torquing that nut on top of the spacer.  Don't forget that because the top of the studs are fine thread, you don't torque them as tight as bolts.  If memory serves the OEM bolts are 75 lb/ft, while the stud nuts are only 55.

Ok, I understand better now, thanks!

[Matt Wilson]

36 minutes ago, Sniper said:

I got a couple of Milodon studs that are longer and may be the ticket.

Do you happen to have the part number, or do you know if Milodon lists them by size?  I called Pioneer and they only have them by application, and no listing by size, so that was a dead end for me.

[Sniper]

I will have to find it for you.

[Matt Wilson]

59 minutes ago, Sniper said:

I will have to find it for you.

Well, if it's not too much trouble, then that's fine, but if you can't find it easily, then maybe I can call Milodon and see if they can spec anything by size.

[Sniper]

IIRC, I just went to Summit racing and looked at the studs they had and found one that I liked.

 

Found it in my emails

 

https://www.summitracing.com/parts/MIL-81254

 

Scroll down and they list 4 packs by diameter and length

 

https://www.milodon.com/head-bolts-studs/main-studs.php

[martybose]

Back when I was doing this ARP had a portion of their website that listed the specs of all of their studs, but I just tried to find it and it doesn't seem to be there any more.  You had to call their technical support phone number to order them anyway.

 

[James_Douglas]

I have been running these on my two 251 flatheads for years now.

 

ARP HEAD STUDS:

 

Studs:         AP3.500-1LB (7/16 x 3.5 stud w/broach)

Washer:      AAPW1316N (Washer 1/16ID 13/16OD non-Cham) I think I used chamfer ones on the '49 it really does not matter much as the head is dealing with the thread pull back issues.

Nut:            APN1116 (7/16-20 Hex Main Nut)

 

If I was doing it again, I may try and get a few head studs a 1/4 inch longer of thread at the top (if the shaft does not stick up to the flat on the head and allow it to be torque correctly)  so that if you wanted or needed to put any kind of mounting plate under the nuts you would have plenty of room to do so.

James

[Dodgeb4ya]

A picture of factory 30" DT  mounted twin carb linkage brackets mounted to head ...

ARP studs were used ..you might call ARP if needed for long enough length if others cannot help.

Good to have stud stick up for sure.

[Matt Wilson]

Thanks to you all for the replies so far.  You guys are giving me ideas for other ways to mount things, so that's good.  I still really have a preference to have studs that will protrude far enough above the head nut that I can add things later without having to remove the nuts (or bolts if I end up using bolts) to put something underneath, but I may not be able to go that route.  I may have to decide up front all the things that I'm going to want up there and mount them all under the nuts.  I would just prefer the flexibility of doing it the other way.

 

I called Milodon this afternoon and their studs have 1" of thread at each end, like ARP, but it seems that they are more expensive than ARP.

 

Having said all the above, I do have a set of studs I bought from Vintage Power Wagons that would barely do what I want to do, but I'd have to use a somewhat thin nut for the head nut (27/64, which is 0.42" tall, so not as tall as the 0.5" tall nut that ARP and Milodon recommend), omit the flat washer under the nut, use an extra-thin nut to hold the accessory in place, and no lock washer under that accessory nut....and then I'd have a couple of threads protruding above it all.  Also, the VPW studs don't have as much thread length available to go into the block (0.72" vs. 1" for the other brands).

 

Can anyone tell me how tall the factory nuts are (when studs are used)?

 

Another question:  Are the studs supposed to be threaded all the way into the block until the shank is against the block?  The reason I ask is because one of the ARP reps I spoke to said I should not do that and should instead leave the stud protruding about half to one full thread above the deck.  He said that if I run it all the way down, I run the risk of pulling the threads out of the block when torquing the nuts.  On the other hand, the Milodon website states the following.  So who's correct?

 

Edited February 16, 2022 by Matt Wilson

[Matt Wilson]

Deleted for accidental double-post.

Edited February 16, 2022 by Matt Wilson

[Sniper]

ARP's instructions state the following

 

"Screw studs into the block “HAND TIGHT ONLY”
 

Zero mention of any threads sticking out.

 

Remember, the Milodon studs are available in 1/4" increments in length.  So you can almost spec the exact length you need.  Not sure about ARP.

 

Edited February 17, 2022 by Sniper

[9 foot box]

   You have already bought some VPW studs, but they also list a longer stud for accessories. You can see that Dodgeb4ya brackets are pre-planned and torqued to the block, and not added to the top of the heavy head nuts. It looks cleaner in my opinion. 

[Matt Wilson]

15 hours ago, Sniper said:

ARP's instructions state the following

 

"Screw studs into the block “HAND TIGHT ONLY”
 

Zero mention of any threads sticking out.

Ah, that's good to know, thanks!  I didn't think to look on their website to verify what the rep told me.  I just figured he was giving me ARP's position on this.

 

16 hours ago, Sniper said:

Remember, the Milodon studs are available in 1/4" increments in length.  So you can almost spec the exact length you need.  Not sure about ARP.

 

ARP offers studs in 1/8" increments.  It's not so much an issue with the overall length, but rather the length of the upper threaded section.  That section is only 1" long and it's difficult to fit (in order from bottom to top) a flat washer, a head stud, a bracket to hold an accessory, a lock washer and another nut in that 1" length.  I may be able to do it, though, if I choose washers and nuts carefully.  Looking through McMaster-Carr's offerings, there may be a combination of these things that will let me do this, but it will be tight. 

 

Too long a stud and the head nut will bottom out ("shank out") on the shank of the stud.  I can compensate for this by adding a washer under the nut, but then I run the risk of the upper nut (that holds the accessory bracket) extending beyond the top of the stud and not getting adequate thread engagement.  I think it can probably be done, but it'll be tight.

[Matt Wilson]

11 hours ago, 9 foot box said:

   You have already bought some VPW studs, but they also list a longer stud for accessories. You can see that Dodgeb4ya brackets are pre-planned and torqued to the block, and not added to the top of the heavy head nuts. It looks cleaner in my opinion. 

The studs I have actually are the longer ones.  I even called VPW to double-check their long stud length vs. mine, just to be sure they shipped me the right ones and that checked out.  I also asked them if they happen to have any longer ones, but they don't.

 

I agree that the pre-planned approach looks cleaner, and I may still have to go that route, but it would offer a lot more flexibility to do what I'm thinking of doing.

[Matt Wilson]

If I decide to do like you guys have suggested and mount the brackets under the head nuts instead of on top of them, there are some brackets I know I want in place from the start (horn, throttle linkage).  But if I decide later, after running the engine for some time (maybe a few thousand miles), that I want to add some more bracketry under some of the other nuts, will it be a significant risk to remove just those nuts and reinstall and re-torque them?  Or should I completely remove the head and replace the gasket at that time, as part of the process of installing the new new brackets?  I've heard of people removing and reinstalling just the head nuts or head bolts of interest, but it sounds like it could be a little risky.

[Sniper]

Last summer I was working on my girlfriend's grandfather's Model A.  I had to take a nut off of one of the head studs to pull the distributor.  Took it home to redo the distributor and the next weekend I was back to put it in.  I had left the nut off for that week and when I was checking fluid prior to a test fire the oil pan was full of coolant.  Seems it leaked down with that nut off.  Not sure it applies to our stuff but I won;t be doing that again without draining the coolant first.

[Matt Wilson]

Well, that's certainly a data point in favor of not doing that.  Probably good enough reason for me to avoid it.

[Young Ed]

1 hour ago, Matt Wilson said:

Well, that's certainly a data point in favor of not doing that.  Probably good enough reason for me to avoid it.

Every flathead I've ever installed was done by using 2 head bolts and a chain. Bolts were then retorqued. Never had a problem with the gasket however all of these would have been drained of coolant. 

[Matt Wilson]

13 hours ago, Young Ed said:

Every flathead I've ever installed was done by using 2 head bolts and a chain. Bolts were then retorqued. Never had a problem with the gasket however all of these would have been drained of coolant. 

Hmmm, good info, thanks.