head bolts or studs

[LEAZER48]

I am rebuilding 24 stud flathead, all studs were removed ( some broken) so they all need to be replaced, new stud kits are pricey, can high grade no. 8 bolts be used instead, stock heads are being used.

[tubman]

I like head bolts, but I am an "8BA guy". I do know that flathead Ford blocks have a special thread pattern that is not compatible with regular "hardware store" bolts. Plus, the "hardware store" bolts will have a 5/8" head versus the 11/16" heads Ford used. If I were in your shoes, I'd try to find a set of 8BA headbolts. They are available from a number of sources.

The last thing you should do is to "chase" the threaded holes in the block with a regular tap. It will ruin the special thread pattern that Ford machined into these blocks. I use an 8BA headbolt with grooves cut in them to "chase" the threads. :

You may want to check out this thread to see how I keep the heads from moving around : https://www.fordbarn.com/forum/showt...light=aluminum.

[flatjack9]

I have used the grade 8 bolts when using after market heads. Never had a problem with leaking.

[Andy]

I used stainless bolts. I was very happy with them. I would have never gotten the heads off with studs when the gasket glued the heads on.

[Ol' Ron]

I use Bolts. Torqued to 45/50 lbs for 3 heat cycles regardless of application.

[19Fordy]

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Avoid studs if you can unless you're going for the LSR. Use bolts.
Makes removing heads much, much easier.
You will be happier in the long run.

[Flathead Fever]

The last thing you should do is to "chase" the threaded holes in the block with a regular tap. It will ruin the special thread pattern that Ford machined into these blocks. I use an 8BA headbolt with grooves cut in them to "chase" the threads. :

You may want to check out this thread to see how I keep the heads from moving around : https://www.fordbarn.com/forum/showt...light=aluminum.[/QUOTE]

He is absolutely correct don't run a tap into your block of any kind!!!! I did it on my first flathead engine. I know two other people that did it and all of our studs leaked, even with gobs of Permatex on them. Not just with the engine running but just sitting there in the garage. It would leave puddles of coolant on the finned heads. I finally used blue Loctite on mine to seal the threads.

I was a mechanic for 30-year's and I never knew there were different classes of threads? Very few bolts on modern engines screw directly into coolant passages. There are some water pump bolts that do but that's about it. A flathead is a whole different beast.

I "think" there are three different classifications of threads? There are loose fit threads, like the regular grade five hardware bolts. Then there are really tight threads. you will never find for for sale. Those are specialty bolts, probably manufactured for special applications. The threads are so tight they create an interference fit. Its like running a lock nut onto a bolt. The studs have resistance screwing them into the block. That is why they are so hard to get out and they can break off. That resistance is what makes your seal so the studs do not leak. All the old books tell you to run a tap into all the holes when rebuilding all engines. Don't do it on a Flathead Ford head stud hole!!! Run a tap into the block and you have removed the metal that made it an interference fit. I'm beginning to thing the more rust and junk I leave in the stud hole the better chance I have it won't leak.

If you look at a factory photo of them installing the studs. It appears they just grab a stud and run them down with a impact with no sealer on them. That thread fit is so tight they can't possibly leak.

[Flathead Fever]

I just found this site on the history of a Flathead Ford Engine Rebuilding Factory.
Neat photos! The first thing I noticed is they don't remove the studs. I don't blame them. They would gout of business if they had to do that on each engine. The next thing I noticed was those K.R. Wilson engine stands with no bases, just bolted to the floor. I wonder if those big drip pans were a K.R. Wilson accessory or something these guys made? Wouldn't it be fun hanging out in this place for a day!

http://theoldmotor.com/?p=169559

[deuce_roadster]

I prefer the studs and have all the retorquing wear on the nut end. That deck is thin. If you have aluminum heads, you retorque a lot. I also like that the stud nuts are fine thread and believe you get a more even clamping. That is just me. I believe that Ford went to bolts in 49 to make assembly faster and cheaper, not necessarily because it was better. These blocks are old and I do everything I can to extend their life.

[32phil]

There has been quite a bit of discussion on bolts vs. studs here on the Barn.
I suggest using the Search Function and reading the threads.
You will then be able to make an informed decision on how to proceed.

[philipswanson]

Check with ARP.

[GOSFAST]

Originally Posted by philipswanson

Check with ARP.

With respect to ARP main bolts OR studs we were instructed by them a while back already to "sand the bottoms of the new washers by rubbing them on some 220 grit sandpaper before installing and torquing them up". This is relevant only when using/installing brand new aluminum heads.

Their claim is you MAY not be getting the correct torque on them during the final installation??

We stock and sell many of these ARP head stud kits specific for the Flatheads and have begun placing our own paperwork in each package explaining this issue!

Just a "tip" here pertinent to this post.

With regards to the heads "sticking" to the studs over time and being difficult to remove down the road we consider this a non-issue here.

One of the main reasons behind us "pinning" the heads to the blocks is due to fact that most mfrs now size the holes on the larger side to help with this very specific issue. We pin almost all builds now, I will say the method above with some aluminum sleeves is not a bad idea either if you can accomplish it without any major issues. Our "pinning" allows for room/space around ALL studs, less chance of "corrosion" on the studs down the road.

Thanks, Gary in N.Y.

P.S. Just to add here, 99% of our Flathead builds get studs, installed with Permatex #1 (hard-setting) and so far have not experienced one single "leak". We always run an H-3 tap (not a thread-chaser) through the existing holes in the decks and I can't recall re-torquing any heads with our method here (with the ARP's)? One more item I would add here, in order to avoid "pulling" any of the existing threads from the decks on final-assembly we torque the block plate up to 85# as a test during mounting it, if all the threads hold we back the torque to the correct number for the final honing! Also we NEVER install any anti-freeze ahead of time until we know 100% there are no leaks, the anti-freeze will "retard" any minor seepage from sealing itself up!

[JSeery]

I prefer studs, but the are arguments on both sides.

[Step-down]

I used 8ba bolts in my 59ab with stock heads , worked great .