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Re: Head gasket

PostPosted: Sat Sep 12, 2020 12:28 pm
by bedrockjon
sacrificial rod, same as in a home hot water tank, theory is water wants to corrode, give it something to corrode and it will not corrode head material as fast,

or some kind of mafia style bribery thing

Re: Head gasket

PostPosted: Sat Sep 12, 2020 3:57 pm
by cornbinder89
Yeah, its there to stabilize and hold the core sand in place. For it to be a sacrificial "rod" it would have to be of different metal than the head (zinc is most common). When casings are made with "coolant passages" green sand is used where you don't want cast iron to be. After the casting the sand is shaken out but the rods used to hold it in place can't come out. You will see them in lots of castings with internal passages. They will be in the block and head.
If you picture a cut away of a head or block, you have iron surrounding a "void" with cast iron all around. For that to happen you must put something in the mold to prevent the iron from forming one big lump. How do you "suspend" something in the center of the pour? you put a rod through it the extends right through the mold, After the pour cools, the rod is trimmed where it stick out and left in the void where it held the sand.
If you were really anal , you could try and cut it into little pieces and extract through a hole, but it will not do any harm where it is.

Re: Head gasket

PostPosted: Sat Sep 12, 2020 5:39 pm
by Bobby K1
C89 thanks for the lesson. I guess I must be really anal because I removed it all; figured it wouldn’t hurt anything .
Pulled a couple plugs to get a quick read. Was only twenty miles on them but I did it anyway. Mostly wanted to look at #3 as it a sign of moisture in the squish chamber. Dry and clean so far.
Started installing remote Anderson connector for battery maintenance and maybe a jump if needed.

Re: Head gasket

PostPosted: Sat Sep 12, 2020 5:51 pm
by cornbinder89
I've made exactly one mold and and the metal poured was aluminum. It was in shop class, back when public schools had such a thing, but the shop teacher made sure we knew the basics and he was the one who told us about the rods or wires.
He posed it as a question, how would you make a coolant passage in a block casting? He let us stew all period before telling us the answer. None of came up with it on our own.
It was fun pouring aluminum, but I would like to try cast iron someday, will not likely happen at my age.

Re: Head gasket

PostPosted: Sun Sep 13, 2020 7:04 am
by Bobby K1
Ah yes..shop class. A shame to see them go. If nothing else it would instill an idea of what it took to make things. One Of the shop teachers I had bucked the system and let us do some auto repair. It was before the regional tech schools were built. I put a new camshaft in a 57 Chevy in-line six. #5 cam lobe rounded. Seen several since then with the same problem . I also learned some rudimentary stuff about lathes that helped get me a job after my military tour.

Re: Head gasket

PostPosted: Sun Sep 13, 2020 3:12 pm
by bedrockjon
Dodge inserted sacrificial rods in the blocks, blogs on it in the Dodge groups

Re: Head gasket

PostPosted: Sun Sep 13, 2020 3:49 pm
by cornbinder89
I am not discounting sacrificial rods, to be effective they MUST be of different material than the item being protected. I use SCA in my coolant. It deposits a sacrificial layer on the liners of the engine to protect them
Iron rods in a cast iron piece are left over from the casting process, they provide no protection.
From a foundry manual ripped from the net
"Large or complicated cores need proper arbors or reinforcing rods in the sand to permit handling of the unbaked core and to help support the baked core in the mold"

Re: Head gasket

PostPosted: Sun Sep 13, 2020 4:01 pm
by nikkinutshop
Here are two examples of castings. The grinder is a school shop project and the airfilter cover is a home shop casting. 433

Re: Head gasket

PostPosted: Sun Sep 13, 2020 4:27 pm
by cornbinder89
Casting is something I think we all take for granted, simple casts with no internal voids (coolant passages) are simple enough, but when it gets involved, it becomes a real art, and less of an "industrial process".
Even simple casts like a cast iron cook stove can be a work of art depending on the skill of the person making the molds.
I was discussing a 1906 "Glenwood" cook stove with someone who knew casting, his comment (he also had one of the stoves) was he had never seen such fine castings in his life, the finish was not machined from the rough casting, but was inherent to the cast itself.

Re: Head gasket

PostPosted: Fri Oct 30, 2020 2:20 am
by chapindesign
I used the ARP studs. I did this last weekend.