Cylinder Head Plug

[SoCalCoupe]

Originally Posted by Kube

I have authentic brass plugs for this.

Found an acceptable hex head 3/8" NPT brass plug on Amazon and installed it loosely into the head sitting on my office shelf. It's obviously the right choice. It will snug down nicely when I actually install the head on the car.

Originally Posted by glennpm

The original poster needs to tell us if he really re-tapped the hole because a 5/8 will go in a few threads and then the taper will stop it IF checking by hand and not using a tap wrench

NOOOO! Nothing got re-tapped. Just ran the tap down the hole a few turns with my thumb and forefinger to check the size. No material whatsoever was removed from the head.


There's no substitute for practical experience. Tapping into Ford Barn to gain the benefit is awesome. I don't know what people did before the internet. Guess they just screwed things up a lot more.

[38 coupe]

Originally Posted by SoCalCoupe

There's no substitute for practical experience. Tapping into Ford Barn to gain the benefit is awesome. I don't know what people did before the internet. Guess they just screwed things up a lot more.

Yes, the curse of the dreaded previous owner. I got lucky growing up with a dad that worked on old Fords as a hobby, and growing up in the Early Ford V8 Club. I only screwed up some things!

[glennpm]

Originally Posted by SoCalCoupe

NOOOO! Nothing got re-tapped.

There's no substitute for practical experience. Tapping into Ford Barn to gain the benefit is awesome. I don't know what people did before the internet. Guess they just screwed things up a lot more.

There were a lot more telephone calls, letters and activity in the Ford V8 Club too. It is great having the internet though.

"It's interesting to see the confusion "Normal" people" react to mechanical things????
Gramps"
That's for sure!!

Glenn

[cadillac512]

Originally Posted by glennpm

There were a lot more telephone calls, letters and activity in the Ford V8 Club too. It is great having the internet though.

"It's interesting to see the confusion "Normal" people" react to mechanical things????
Gramps"
That's for sure!!

Glenn

Good thing we're not "normal" !


Terry (but still confused )

[itslow]

From the standpoint of ensuring your aluminum cylinder head isn't the part that corrodes, using an aluminum plug with an anti-seize or other intermediary to prevent galling is the best choice.

Both stainless and brass plugs will induce galvanic corrosion with the aluminum, with a brass plug being slightly worse than the stainless.

If you can't find an aluminum plug a zinc-plated steel one would be a better option, although the exterior of it could develop surface oxidation depending upon the environment in which you live.

[SoCalCoupe]

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Originally Posted by itslow

From the standpoint of ensuring your aluminum cylinder head isn't the part that corrodes, using an aluminum plug with an anti-seize or other intermediary to prevent galling is the best choice.

Both stainless and brass plugs will induce galvanic corrosion with the aluminum, with a brass plug being slightly worse than the stainless.

If you can't find an aluminum plug a zinc-plated steel one would be a better option, although the exterior of it could develop surface oxidation depending upon the environment in which you live.

The brass plug is prettier and more period correct but you're absolutely correct about the corrosion. I'd rather have the plug be the sacrificial anode than the head.


I did purchase an aluminum plug but it screws in with an Allen wrench. Doesn't look quite right. A hex head would look better. Couldn't find one though. All the hex head aluminum plugs were anodized either red, black or blue.



BTW, it never ceases to amaze me why people buy aluminum radiators for steel cars. The thin aluminum is the sacrificial anode rather than thick steel.

[tubman]

That's what magnesium sacrificial anodes are for.

Check out the Galvanic Table.

[Bored&Stroked]

Personally, I don't like aluminum plugs in aluminum heads - as they can be very difficult to get back out and aluminum is a soft material. But, do what makes yah happy! LOL

[Jack E/NJ]

>>The brass plug is prettier and more period correct but you're absolutely correct about the corrosion. I'd rather have the plug be the sacrificial anode than the head.>>>I did purchase an aluminum plug but it screws in with an Allen wrench. Doesn't look quite right. A hex head would look better. Couldn't find one though. All the hex head aluminum plugs were anodized either red, black or blue>>>


Color anodizing can be easily removed with a scouring pad. But if you don't want to scour, you could also use a nylon pipe plug from Ace Hardware or Tractor Supply. Then paste aluminized duct tape on top so it blends in. All kinds of possibilities for artistically plugging your hole.

[Bored&Stroked]

"Jack E/NJ;2248981]>>All kinds of possibilities for artistically plugging your hole. "


Jack, this made me a bit nervous . . .

[Drbrown]

In discussing the type of plug to use, I think it's worth noting the use of aluminum heads with iron blocks begs the issue of dielectric corrosion between the dissimilar metals. Example: In 1984 Cadillac switched to aluminum heads and the problem of dielectric corrosion surfaced (yes, I have one). They then went back to iron heads. The preventive prescription is to use a coolant with good quality anti-corrosive additives AND TO CHANGE IT about every 3 years since additives become ineffective. You have aluminum heads so the issue of dielectric corrosion is present. If you use a good coolant I suggest that functionally a brass or even black iron plug will work; brass better of the two.

[Jack E/NJ]

For nervous nylon nellies.


https://www.protolabs.com/resources/...lon-vs-delrin/

[itslow]

Originally Posted by tubman

That's what magnesium sacrificial anodes are for.

Check out the Galvanic Table.

You can still get localized corrosion at the interface between the two materials.

An anode dangling from the radiator cap can help, but only at a less effective macro level since the conductive path between the two will be so disconnected. Ideally one would put a sacrificial anode each head as well to be truly effective.