Topic: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

I don't have cast iron exhaust manifolds on my car but I recently learned about this "old school" technique and thought it was sufficiently lemony to pass on.

Q: Has anyone ever done this before?

Seems like a wonderfully bad idea to increase the internal volume (and hopefully the flow) into/out of cast iron manifolds at the expense of material strength.

https://www.youtube.com/watch?v=qhXZ7P1_RwU

More discussion here
https://forums.probetalk.com/showthread … 1701179774
https://forums.probetalk.com/showthread … 1700961205
http://www.dsmtuners.com/threads/acid-p … ld.445630/
http://speedtalk.com/forum/viewtopic.ph … mp;t=33493

Random tidbits
- Muriatic (concrete cleaner or pool chemical), hydrocloric, or sulfuric acids (battery) are popular choices
- You can fill the intake with water and measure the amount to determine how much internal displacement you have gained
- Alternatively, you can also use a metal sealing plate the thickness of the amount of metal you want to remove (provided it's the same material). When the acid eats through that plate, you know roughly that this is the amount of thickness removed from inside

I'm curious if anyone has tried this for the Lemons car.
-g

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Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

Porting involves a lot more than increasing volume.  Actually, increasing volume alone can hurt flow, depending on how its done.  A lot more goes into a good port job- which is why it takes a die grinder and about 10 hours to port a head.

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Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

Yea, I'd be scared to just fill with acid and hope for the best. Depending on the age and condition of the manifold I could totally see it eating different places faster and leaving you with weak spots just waiting to break through.


Careful with Muriatic acid too. It can outgas through it's plastic container. If you leave it in your garage you will find that anything steel will start to rust really badly.

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Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

I'm gonna try boring a mini block using this method.

Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

gunn wrote:

Muriatic (concrete cleaner or pool chemical), hydrocloric, or sulfuric acids (battery) are popular choices

Muriatic acid is just one of the old-timey names for hydrochloric acid. It's the same stuff but for some reason the obsolete name persists within certain industries. The cool kids call it spirits of salt.

Similarly, the element niobium (Nb) is still called columbium (Cb) in some modern metallurgical contexts. This usage can be rather startling when first encountered, should one ever be in the market for sheets of the stuff.

1982 MG Metro 1300: IOE 2015 Pacific Northworst GP, Longest Distance 2010 Cd'L Box Wine Country Classic
1980 KV Mini 1: Worst of Show and Fright Pig Supremo 2009 Concours d'Lemons
1978 H Special: Second-Round Elimination 2010 Lemons Pinewood Derby at Sears Pointless
1967 SAAB 96: IOE 2012 Pacific Northworst GP, Organizer's Choice 2022 Hell on Wheels California Rally

6 (edited by DRVOLKS 2017-10-10 12:00 PM)

Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

It is used on some racing class for a ported head as a cheater setups.
If you need the head ported just do it and be done with it. I would look at the spring,shocks,brakes tires scaling first before you look for more power.
Drvolks

Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

mharrell wrote:

Similarly, the element niobium (Nb) is still called columbium (Cb) in some modern metallurgical contexts. This usage can be rather startling when first encountered, should one ever be in the market for sheets of the stuff.

Yeah, columbium is the name historically used in America before IUPAC chose the European name to be standard, those pinko scum. Most American industries still use it. In fact, most metallurgical standards I've seen actually specify total columbium/tantalum since those two elements basically behave the same way in steel alloys and are difficult to differentiate in practice.

But enough about that, why were you in the market for sheets of Niobium??

Re: Ever heard of Acid Porting for cast iron intake/exhaust manifolds?

SpaceFrank wrote:

...why were you in the market for sheets of Niobium??

Diamond-anvil cell research, so my group was interested in very small sheets of the stuff. We were looking into various possibilities for composite gaskets.

1982 MG Metro 1300: IOE 2015 Pacific Northworst GP, Longest Distance 2010 Cd'L Box Wine Country Classic
1980 KV Mini 1: Worst of Show and Fright Pig Supremo 2009 Concours d'Lemons
1978 H Special: Second-Round Elimination 2010 Lemons Pinewood Derby at Sears Pointless
1967 SAAB 96: IOE 2012 Pacific Northworst GP, Organizer's Choice 2022 Hell on Wheels California Rally