In Reply to: Re: CYLINDER HEAD STUDS, HEX NUTS & HEX BOLTS posted by Tim Daley(MI) on September 08, 2018 at 09:34:40:
I've read that the studs on Ford flathead engines have rolled threads so you should not chase the threads in the block using a regular tap as it will screw up the sealing capability of the stud or the bolt. When doing my 8N engine I removed the original head nuts and studs primarily because I installed new sleeves and the engine had had a head gasket leaking problem and I wanted to surface the block to bring the sleeve tops to the same level and ensure a good sealing surface. I also had the head surfaced.
I reinstalled the original studs after giving them a full wire brush cleaning. I cleaned the block threads using lacquer thinner, a pipe cleaning brush from Home Depot that I cut off to use in the drill followed with a cloth patch on a pistol bore cleaning rod giving very satisfactory results. I reinstalled the original studs using aircraft gasket seal and torqued them into the block using 10 ft-lb torque. I let them set up overnight before installing the head using the original head nuts and torquing in increments to 55 ft-lbs with a Felpro soft gasket. I had a gallon tank that set up allowed me to start and run the engine less the hood and I warmed the engine after the final torque to operating temperature and let it cool fully overnight and re-torqued to 55 lt-lb. After five cycles of doing this the nuts no longer shifted with the torque and I considered it complete and have no further issues.
I doubt the the bolts, studs or nuts suffer much from the relatively low torque values on these engines and I suspect they are equal to a class 5 fastener in strength. One should consider that these were designed to be worked on,
literally, in the field by farmers and others and the fasteners reused, so I doubt there is much of a strength issue as head gasket changes as well as bearing changes were pretty routine in those days. I prefer the studs and I have also seen several posters on some of the Ford flathead engine blogs complaining of leaking studs after assembly with replacement studs.
I recall in my high school days we built 48 Merc blocks with Edelbrock heads, Isky cams, shot peened stock rods and 0.60 overbore with fairly high compression ratios (for the time) and just reused our original head nuts and rod nuts never thinking more about it. Of course we had those nice slip over chrome acorn nut simulators to dress up the heads!
Just my 2 cents.