There are two threaded plugs in the head at about intake/exhaust 2 and 5. These go into a coolant passage, right?

I was going to remove these along with everything else removable, so the head could be cleaned and the coolant passages de-rusted. The “crown” of both broke when trying to remove them. The main body of the plugs are still there so they are still ceiling. I’m pretty sure I can get them out, but as these cannot be reused, are new plugs available? Also, is there any point in removing them in the first place (convenient afterthought)? Can the coolant passages be de-rusted just as well without removing them? I’m going to use citric acid for removing rust in the passages.

I tried to remove one of those once. It also partially broke, but did not move the threads, so sealing is fine. I would not touch them and clean the passages chemically. I take my heads to machine shops and have them put them in a vat to remove all the bad stuff.

Lou

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Home of Slant6-powered fun machines since 1988

Okay, thanks for the info. It’s best that I leave the plugs alone then. I suppose the watery citric acid will fill up all of the cooling passages anyway.

I’ll give the citric acid a try. The machine shop seems extra busy now in summer time and I’m not sure how well they bother doing this kind of cleaning job. We’ll see how it goes.

Molasses and water is another option to get the rust out.

Lou

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Home of Slant6-powered fun machines since 1988

Have it " Hot Tanked" at the machine shop.

Better than Molases/ water in my opinion.

Good luck!

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http://www.youtube.com/hyperpack

I thought all the hot tanks were gone? Don't know anyone in my area that still uses chemicals and heat to do a great job! Wish I did.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I'm not sure what the machine shop that I used (around 2020) does or if it's a true hot tank, but they returned the block and other items with some sort of chemical cleaning that took off rust and grease, and left a dark gray coating over everything.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

I don't know what they are using currently, but I know that at one point they used a sodium hydroxide solution. Works great on ferrous metals. It does melt aluminum so that is a big no no.