Internal Intake Rust [Archive] - Team Camaro Tech

: Internal Intake Rust


Z10396
Apr 22nd, 09, 07:14 AM
Hi Guys,

I am currently in the process of putting my 396 back together. I had a bunch of machine work done to the crank, rods, block, heads etc. I took the intake manifold out of storage to clean it up and it is pretty rusty. I want to get the insides /runners cleaned up but I am unsure what to do or use. I am hesitant to to soak it in any type of acid out of worries of tainting the internals. Any recommendations?

Thanks

dyno jonn
Apr 22nd, 09, 07:57 AM
Hi Guys,

I am hesitant to to soak it in any type of acid out of worries of tainting the internals. Any recommendations?

Thanks

You can do like the people that restore old cast iron pans do. First they soak them in lye for a few days to remove carbon and oil (use a plastic container). Lye also removes most paints. Rinse well, then soak in a 50/50 mix of white vinegar and water for as long as it takes to remove the rust (usually a couple of days maximum) aided by a wire brush if the rust is stubborn. I do this on lots of metal parts, but keep lye and vinegar away from anything other than steel as Aluminum tends to disappear, so be warned. Google "cleaning cast iron" for more info. ;)

Be sure to read the instructions on the container if you use lye. Always add lye to water, never add water to lye. Eye and skin protection won't hurt either as lye can burn you pretty badly if you mess up. Lye is available at most grocery and hardware stores, also at Lowes.

Z10396
Apr 22nd, 09, 10:14 AM
Thanks Jon. I read to use straight vinegar. There was also a recommendation to add peroxide to speed up the process. What do you think?

dyno jonn
Apr 22nd, 09, 02:05 PM
Straight vinegar will just eat the rust faster. Haven't tried Hydrogen Peroxide, I'm not in that much of a hurry. Besides, I'm too cheep. :D

speedfreek
Apr 22nd, 09, 03:59 PM
Let the machine shop hot tank it.

Z10396
Apr 22nd, 09, 07:33 PM
I was there yesterday. He told me to dip it in acid.

Let the machine shop hot tank it.

Steptoe
Apr 22nd, 09, 10:56 PM
Let the machine shop hot tank it.
You should have asked them when they did the block heads etc...throw them a couple 6 packs.

Z10396
Apr 23rd, 09, 07:04 AM
It is my understanding that hot tanking doesn't really remove rust well at all.

You should have asked them when they did the block heads etc...throw them a couple 6 packs.

Steptoe
Apr 23rd, 09, 02:12 PM
The machine shop I have used for yrs..and it is a small 1 man business large workshop...its tanked for a couple days, a potent mix of chemicals, then put in a cabinet where it is steamed sprayed ...goes thru a big wash cycle...comes out as if freshly cast.
It is not caustic cause it also does Al parts...caustic eats Al out.

Rogers Performance
Apr 23rd, 09, 06:19 PM
Take it to a shop that has a steel shop machine and have it shot blasted.

Z10396
Apr 23rd, 09, 07:15 PM
Take it to a shop that has a steel shop machine and have it shot blasted.

I will definitely keep these recommendations in mind. Right now I am pickling the sucker! We will see what happens. It has been in the vinegar for 24 hrs and I haven't seen any results but I will give it time. I cleaned it with marine clean first so that it was not tainted with oil.

lluciano77
Apr 23rd, 09, 09:26 PM
I was there yesterday. He told me to dip it in acid.

But then where do you dispose of the acid when you are done? That would be a fair amount of acid to have to mess with.

dyno jonn
Apr 23rd, 09, 10:58 PM
But then where do you dispose of the acid when you are done?

Vinegar is 4-6% acetic acid and not a real threat to most systems, but is strong enough to do the job, even when diluted. I use it to clean exhaust manifolds and they end up looking nearly new.

Z10396
Apr 24th, 09, 04:47 PM
Jon,

Its starting to work! I pulled it out of the "pickle barrel" this afternoon after work and the bottom has large spots of clean cast iron. I wire brushed a few other spots and clean cast showed through. I will pull out again tomorrow and brush it and maybe even pressure wash it and then dunk it back. I was also thinking about a pipe cleaner type busher to get in side with. I will keep you posted.

Z10396
Apr 26th, 09, 12:29 PM
Well, I just pulled it out of the vinegar and pressure washed it.

I am truly amazed. The thing is mostly fresh cast iron now.

I am going to soak it another day or two and take it out and pressure wash it one more time.

The inside is basically spotless now. Surprising after basically sitting outside for the past twenty years.:hurray: