Head number

[jmujica]

I have a 46 Mercury with a flathead v8. I need to change head gaskets and want to know should I change nuts, washers and studs. Also in the center is a number 59A-B . What does that number refer to.

[tubman]

Ford used high quality steel in all of it's components, and they were reused as matter of course throughout the years. That being said, almost 80 years have passed since the original components on the engine were new and anything might have happened since. Or, they may have been replaced with an ARP stud kit last year. The bottom line is that they are going to have to inspected closely to know exactly what you have before you can decide. Certainly, a new set of ARP studs would be the safest choice, but that's a lot of dough. I'm an "8BA guy" and I save all the 8BA head bolts I come across; I sort through them and find the majority are still usable. In the final analysis, it depends on your experience level and budget.

Back in those days, Ford generally had a two digit suffix for each grouping of similar years. The first digit was the units digit of the first year the component was released, and the second digit was the units digit of the displacement of the engine. There could be a third and even a fourth character which was usually alphabetic that had to do with subsequent minor versions. Thus, "59A" denotes a component for a series of engines first released in 1945 with a displacement of 239 ci. All Ford (and Mercury) engines from the late war years through 1948 were almost identical and all were of the 59 series. I'm sorry that I can't pin down the "A", "A-B" meaning other than they were subsequent minor changes. Hopefully, someone out there is an expert on them, but I wouldn't be surprised if they're not.

[Flathead Fever]

I wouldn't mess with the studs. From what I understand they were an "interference thread" to prevent coolant leakage. the studs have a slightly different thread than the blocks and this is what makes a nice tight seal. If you run a tap in the block and install new modern studs, you risk having coolant leaks. I know several people that installed new studs and then ended up with coolant seeping up through the threads.

I have about every factory flathead book made and I have not seen anything mentioning the interference fit on the studs, but I've seen several people mention it. The first flathead I rebuilt I ran a tap down through the block. I had to install longer studs because of aftermarket heads. I put sealer on the threads and severalt of them ended up leaking. Lator I watched a factory video of them installing the studs on the assembly line and it didn't look like they used any sealant. So, the interference thread makes since.

[Kube]

Jmujica, the 59AB head was designed to be used on either the right OR left side of the engine.
There is no need to replace the nuts unless the threads are corroded or you simply want freshly plated nuts for appearances.

Washers? There should be no washers unless you have aluminum heads.

There was truly an interference fit designed between the studs and block. Many have made the mistake of running a tap down the block with subsequent issues from doing so.
Unless you break a stud or one (or more) comes out with the nut, there is no reason to clean the threads in the block. Even if a stud does come out, do not chase the threads in the block.

[tubman]

I think what may have sparked the O/P's original question is the fact that most contemporary cars use head bolts/studs that are designed to be used one time only, as they were designed to stretch a certain amount on installation. (I know I had a shock when I saw a line item for a couple of hundred bucks for "Head Bolts" on the bill when I had the head gasket replaced on my '82 Dodge Rampage.)

Please be assured that this is not the case with the old Fords.

[jmujica]

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Thank you all for sharing your knowledge.