What is the best way to clean the intake plumbing?

'79 5 speed

 

I'm currently sanding mine. I've got the polishing down to about 8 steps.

You'll hear many different ideas, most pretty good from the list.

One thing would work ok, is take a dremel. I'd use bit 428
http://www.dremel.com/HTML/home_fr.html

on the whole spider, this will buff it up and make it shine. One thing I learned is nothing hurts, everything makes it look better.

 

Wheel acid.
<-------

 

You can do a pretty bang-up job "brightening" aluminum engine bits by soaking them in a detergent mixture for an hour or two. I use mr clean in hot water. This takes out any oil residue that's embedded in the surface of the aluminum.

Note that real aluminum parts will oxidize to a grey tone from long exposure to air. The film actually protects the underlying metal from further oxidation, so it's not a bad thing unless you really ned to have bright parts all the time. There are some metal prep chemicals made for pre-paint treatment that may help. Most polishing efforts make apart that looks great for a few days, but slowly goes a little grey unless it's continually polished with Never-Dull ar simichrome or whatever.

More than a few folks ahve resorted to having the parts powder-painted to maintain at least a consistent clor and shine.

 

m21sniper,

What is wheel acid?

 

It depends on what end result you are trying to achieve. It also makes a difference if you have removed the intake from the car and are working on a bench or working in the engine bay.

I believe sniper is talking about most wheel cleaners which are very acidic. They work on clearcoated wheels to remove brake dust but will etch any non protected aluminum.

If you are looking to polish out your intake to a high polish you will need several steps. The best is to remove the system and dismantle. Then use a 3M scotchbright pad on an angle grinder. The smaller 2 or 3 inch pads work best. This will take down all the rough surface and remove the ground parting lines and gates left behind by the foundry when the parts were cast. Not a very good cleaning job on their part. Of course if you have access to professional grinding equipment it works best. You can step up in grit or coarseness of the pad until you get a nice clean smooth finish. Once this is done you will need to start with jewelers rouge and high speed polishing wheel, there are many compounds. First you will want to cut the surface to get all the rough lines and marks out than work your way up in pad and rouge to get a clean polished surface. Heat is a key factor in getting a good polish. Sometimes preheating the metal first will help speed up the process. it is a nasty dirty job so plan on covering yourself from head to toe, wear a mask and work in an area that is not cluttered so you can clean it easily later.

If you just want to clean the intake without changing the factory appearance, I recommend Wurth Citrus degreaser mixed with water in a spray bottle. Strength depends on how dirty it is. Just spray and allow to sit for 5 minutes. Scrub heavy dirt with nylon brush and hose off. I would not hose off a hot engine but you may want to start the engine just prior to hoseing it off to prevent any starting issues later.

Good Luck

 

Thank you Anthony. For now, I just want to clean it in the car.

 

"m21sniper,

What is wheel acid?"

It's a common detailing supply used for cleaning rough cast wheels(our early 928 intakes are also rough cast). It's simply called "Wheel Acid".

Spray it on, wait 30 secs, spray it off, your plenum will look like this:

<--------------------

 

Ceramic coating:

 

Randy's the king of polished engines! That guy spent dozens of hours hand polishing each component of that engine. I talked to a guy in Orlando who did the same thing, and he rolled his eyes: "Uhmm, you have no idea how much work that took!"

-I've used phosphoric acid mag wheel cleaner on my tubes, then Nevr-Dull and eventually...very fine steel wool from the hardware store. If you do this last...you'll have to do it from time to time. I like to open the hood whenever I wash the car and wipe the edges of the body where the fenders attach with my chamios, and then later I usually pick a few things under the hood to wipe down with Armor-All. My engine isn't as hot as Mr.Sniper's or Randy's....but here's an un-polished M28-21 motor.

N!

PS: WEAR rubber gloves when you use the mag wheel cleaner, or the skin on your hands will look like your chamois for a couple of days!

 

I use a product available from heating/airconditioning jobbers...called "Brite Alum"
This stuff is the absolute "berries"...It's intended purpose, is to clean "A" coils, in updraft furnace/air conditioners, and outside AC condensing unit heat exchanger coils. And believe me, its a GOOD product. If you have a "non-fragile" aluminum part, OFF the vehicle...then a soaking for 10 minutes in this product, will yield aluminum to better than "as new" finish. I was amazed. Try it on an insignificant part you have off the car and see for yourself...(and NO, in no way am I, or any freinds or relatives affiliated with this company or product). Just be careful not to get it on anything you don't want to look like its been hot tanked. I can't post pictures...(as I'm a pitiful "Registered User") by definition....but, you should see the intake plenums and manifold on my 86.5, after a brief soaking in this stuff...not polished looking...but, like it was "glass beaded". I'm thoroughly happy, and best of all...this product is $8 a gallon.

 

These products all do a great job of cleaning Aluminum. The problem is they are all caustic. They actually remove material from the surface by etching it and that is why you are left with a like new finish. Particularly if you are working on the car. I would not use any of them. The end result is great but the potential damage to surrounding components and finishes are just not worth it. Any tight tolerance dimensions may eventually be effected by the removal of a few thousandths every time you use it. Eventually it may remove enough material to be a disadvantage. Some products also dry out and damage rubber seals and hoses.

I recommend the citrus degreaser because they are all natural. They don't etch or alter the surface, they actually emulsify the grease and leave a very clean unaltered surface. The product can be used multiple times and won't destroy surrounding components, finishes, your hands or the environment.

Just a thought

 

Hey Cobalt, most of the aluminum cleaners are not caustic. In actual terms, caustic most often refers to basic or free -OH groups that like to attack metals such as alumium. The wheel cleaners are normally acidic with phosphoric leading the pack. Some use Acetic and others, very high strength, use Nitric. Yes, inorganic acids can be caustic, like high stregth sulfuric, but it is generally reserved for loose base groups. Don't use "Easy-Off" oven cleaner on your wheels (NaOH)!!! When you ask for caustic powders or cleaners they always tend to be NaOh or Calcium Hydroxide.

 

Randy, all that work and still a busted up windshield washer reservoir cover? How disgraceful....maybe Tim Murphy will send you one so that the two of you can kiss and make up! Get a new filler neck and cap on that sucker!

Good luck.

Garrity

 

I appreciate your pointing out the correct use of the term.

However, my understanding and use of the word caustic is based on Webster definition. "Capable of corroding or eating away, burning, corrosive".

It is my experiance that these substances attack or eat away at aluminum. Use a wheel cleaner containing these acids on an unprotected aluminum surface and watch it start to attack the surface. If it is high polished it will etch and dull the finish. Acetic, Phosphoric and Nitric especially Sulfuric will attack aluminum. More agressively as you go. If you read the labels on most of the industrial strength cleaners used for cleaning A coils they warn you not to leave on surface too long as it will destroy or damage the aluminum. I am sure there are products out there that are safe but I recommend reading the labels carefully.

I am not a chemist but I deal with cast aluminum all the time. It is my experiance that you don't want to use most of these products on exposed aluminum surfaces. A big mistake I have seen many people do is use these products agressively and not properly remove them after use. They allow the product to dry on the surface and over time they are left with damaged material.

Just my .02 worth.