Cleaning cylinder heads

[Tony H]

I know this is an age old question with dozens of Youtube garbage can hot tanks with who knows what in them. I read that Aluminum Jelly will clean combustion chambers and ports. I am not expecting instant, easy results. Anyone have a method they have used? The closest machine shop is 2 hrs away.

[tbomachines]

On DI cars it is common to walnut blast the valves and ports. I have also done this on my DI car -- walnut shells will not damage the metal but will take carbon and buildup off and make it look like new. You will need a good compressor and ensure nothing gets into the combustion chamber. If the head is off, seems like a decent way to clean it.

[Tony H]

Thanks for the idea. I had considered media blasting after the initial de-gunking. Walnut shells is probably the safest media for internals. My new shop is not up and running yet so no compressor but gathering ideas.

[tbomachines]

Before and after with walnut shells. Harbor freight sells 25lb bags for 20 bucks or so, which is a pretty good deal. The cylinder head here is aluminum (car is a saturn sky), they are pretty gentle. Some more time would get it shiny new, but my main objective was all that nasty carbon buildup. Just make sure to mask any oil and coolant passages as the media gets everywhere.

[engatwork]

You got to have enough compressor to operate the walnut shell blaster.

[Tony H]

Walnut shells did a nice job. I had a large compressor with an aftercooler/water trap that I had to leave when we moved. As most know the air must be very dry or it will clog the blaster. I plan on getting another as soon as I can.

[Tony H]

So I started disassembling and cleaning the heads. I had not received the plastic razor blades and stiff nylon brushes yet and I only had a little carb cleaner so I went to the dollar store and bought a small stiff round scrub brush. In a half hr I had 4 combustion chambers and 1 cyl of ports (including the exhaust port)done before the carb cleaner ran out. The carb cleaner disolved the carbon quickly. Regarding the head gasket surface, I did not have the plastic scrapers but the carb cleaner did clean up the surface some just with the scrub brush. I am confident with the scrapers I can clean up the parting surface perfectly. The valves are in the ultrasonic cleaner.

[Idle]

Not bad at all. I once had some 6.9 heads I didn't trust myself with so I had them professional cleaned.

I should have gone with the carb cleaner. My heads didn't look half as good as these.

[Tony H]

Well it was a short-lived victory. Apparently, I started with the cleanest cylinder. The ones that were burning oil have stone like carbon deposits in the exhaust ports. I got some Dremel brass brushes in a few different shapes to work on it with but still tough. I may have to wait until I get a compressor so I can media blast them. The carb cleaner still works but much less so on the hard deposits.

[Tony H]

I have read the 3M White Bristle Disc is the go to for cleaning aluminum heads without damaging the surface so I am going to give them a try. They would also work on the cast iron block I'm sure. I will post results.

[INSIDIOUS]

2 words. oven cleaner.

https://www.peachparts.com/shopforum/3343217-post31.html

[Tony H]

I used to use oven cleaner on everything but I learned it can be harsh on aluminum and can etch machined surfaces like the head gasket sealing surface. I have read great things about the 3M Roloc Bristle Discs-can't wait to try them.

[Tony H]

Here are the results of the Bristle Brush. There was a small learning curve. For me the slowest RPM with light pressure provided the most controlled cleaning. I used a angle die grinder but it is difficult to control the speed at low RPM/light load. A angle drill would probably work better but I like the lightness/small size of the die grinder. I may try the drill on the other head. Overall I was very pleased with the results. I did not get near the valve seats.

[Sugar Bear]

Looking good!!!

What is the next step?

[Tony H]

These are M117 5.6 heads from a running engine I'm using on a temporary basis for my "Iron Block 5.6" project so I can reduce the number of unknowns on an unproven concept. If I install rebuilt heads that is one more unknown. I want to clean them up before I use them. Once the concept is proven I will have the heads rebuilt. Next step is some kind of "garbage can" hot tank to clean the coolant passages followed by pressure washing to blow out the residue.
Tried out the bristle disc on the block. Still using the white disc it did a really good job of cleaning up the deck. Original machining marks still visible. That was 5 min of work. I'm sure any serious engine builder uses them but they can (should) only be used on a disassemble engine that will be cleaned as the abrasive can hide out and come back later to destroy your engine.