How to clean an engine

[Jrasm]

Hi all,
I was wondering what the best way is to clean up a old and dirty engine. Ideally i'd like to do this without disassembling the engine to avoid all the disassembly/reassembly time. I've seen the threads on the different cleaners that people use which makes sense and looks pretty easy to do. But is that all that needs to happen? My gut keeps telling me i need to sandblast or use a soda blaster to clean off the oxide but i'd really hate to get that crap inside the engine.
How did you clean up the fins and exterior of your old oxidized and grimy aluminum engine?

Thanks!
Jeff

 

[warthogcrewchief]

If you plan on either repainting or polishing the metal out, most finishes are painted on and the finishes have degraded due to grease, UV rays, etc.

Definitely do not use a media blaster as it is difficult to get out of the engine. I used aircraft paint remover (purchased at any auto parts store). Let it sit for a while (10-30 minutes), try not to get it on rubber or gaskets as I'm sure it's not good for it. After waiting, agitate it with a paint brush, tooth brush or whatever you can find. Repeat. After you feel you have it all off, rinse it off. Most of the paint strippers you can buy are soluble.

Don't forget to wear proper PPE (Personal Protective Equipment): rubber gloves and googles/eye glasses. Be sure to have the hose ready in case you need to do a quick rinse.

I've also found that the paint stripper is LESS effective in hot, bright sunlight. It still works well, but found it starts to bubble and degrade much quicker in direct sunlight than in the shade.

After you have bare metal, you can rough it up with a high grit paper for paint prep, or polish it to chrome-like shine.


EDIT: IF all you are doing is just a cleaning, go to a parts store (or even Walmart) and get Westley's Bleche-Wite Whitewall cleaner. It's used to clean tires but does an AWESOME job at cleaning engines. Wash the engine with soap (I like dish soap like Dawn or Joy) and water. While still wet, spray the living tar out of the engine. Start scrubbing immediately with either a tire brush, or a tooth brush. A great alternative would be a brush used for cleaning AR-15's that can be found in the gun section of most stores. When done scrubbing, rinse and repeat. I've done this for years on cars, motorcycles, antique aircraft and many other applications. It works great on grease, tar, dirt, etc. Don't breath it in because it REALLY stinks!

 

[jimboburgess]

is it a good idea to blast an engine with water from the carwash?

 

[Jrasm]

I would guess it's not the best idea as you've got a nice hot engine that now you rapidly cool with water which could cause fractures. but maybe if done slow enough... I've never been in a place where i felt like testing to see.

In my case however, my bike is immobile so i've either got to borrow a pressure washer, or haul it somewhere. Furthermore, i'm not sure that simply washing at a coin-op would be strong enough to get the 30 year old grime that's caked up on this motor.

 

[jetmechmarty]

WD40 does a pretty good job of loosening up the crud on your engine. It will not hurt the aluminum. Let it soak a good while then wash it with soap. You can take more extreme measures with whatever is left.

 

[swan]

Simple Green and a red 3M brand scrub pad for metal works for me every time.

Before

After Simple Green and red scrub pad

 

[BIG E]

Isint simple green corrosive to aluminum parts?

 

[swan]

Nope.

 

[ProSimex]

Oh swan, you and your ability to do things well....

 

[Jrasm]

according to the Simple Green website

Aluminum - Is it safe to use Simple Green® on aluminum?
When used with caution and according to the instructions, Simple Green All-Purpose Cleaner has been safely and successfully used to clean aluminum. Simple Green All-Purpose Cleaner, Crystal Simple Green® Cleaner/Degreaser, Simple Green Pressure Washer Concentrates, and Pro Series™ Simple Green® Automotive Cleaner have been used on aircraft, automotive, industrial and consumer aluminum items for over 20 years. However, caution and common sense must be used: aluminum is a soft metal that easily corrodes with unprotected exposure to water. The aqueous-base and alkalinity of Simple Green All-Purpose Cleaner can accelerate the corrosion process. Therefore, contact times for unprotected or unpainted aluminum surfaces should be kept as brief as the job will allow - never for more than 10 minutes. Large cleaning jobs should be conducted in smaller-area stages to achieve lower contact time. Rinsing after cleaning should always be extremely thorough - paying special attention to flush out cracks and crevices to remove all Simple Green® product residues. Unfinished, uncoated or unpainted aluminum cleaned with Simple Green products should receive some sort of protectant after cleaning to prevent oxidation.
Simple Green has also developed break-through water based cleaners that are safe for use on metals, plastics, rubber and high tech alloys. Extreme Simple Green® Aircraft & Precision Cleaner and Simple Green® Pro HD are available on both the industrial and retail markets, respectively. These products were initially developed for the aircraft industry and extensive testing shows that they are safe and effective on a variety of metals and other sensitive surfaces even in the most extreme circumstances.

Simple Green® Stainless Steel One Step Cleaner & Polish is another option for cleaning polished aluminum. This product is designed for light duty metal cleaning and polishing.

So it's safe if you're careful and don't leave it on for too long.

 

[swan]

Yup.