Rust in Intake Port??

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mopowers

mopowers

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I'm cleaning up a couple 906 cylinder heads for a stock 400 and found a couple intake ports with some rust scaling. Someone obviously stored the engine outside and allowed some water to pool in a couple ports.

What's the easiest way to eliminate this rust scaling??? Do they make tiny wire wheels for die grinders??

I'm trying to avoid a trip to the machine shop, as these heads and engine will just be used temporarily to get the car on the road while I build the 470ci replacement. I'm hoping to clean the rust up and salvage the seats with some shade-tree valve lapping.

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RustyRatRod said:
Soak it overnight in white vinegar.
Click to expand...
Agree, just tape the intake port and fill with vinegar. Should clean that right up. Muriatic acid (pool acid) works very fast but may flash rust after, just hit it with some neutralizing baking soda rinse and then a shot of WD-40.
 
All the ports in my 318 302 heads looked like that. They cleaned up when I ported them
 
Naval jelly. Easy to apply, easy to remove, acts quick. Oil heavily after with wd40, 3 in one, motor oil or similar. I like gear oil because that stuff sticks to everything but it stinks.

Muriatic acid will fume and rust everything in the room, unless you're far more careful than I was/am. It will even eat chrome off your tools... Expensive lesson (I etched some floorboard with 1/2 cup of muriatic and stored the well sealed bottle in the garage with the car and tools.. Wasn't well sealesd enough).

Pressure washing is fine, but drying the whole head before rust forms can be tough, and it may not remove everything.

Vinegar is great, but trying to plug everything and isolate just the port will be a pain in the aft end, and it won't touch anything that has any oil or other occluding agents present (even fingerprints can slow the vinegars action). If left long enough, it will get through light oil but will also etch more off of surrounding surfaces. If you're gonna soak the whole head, no cheaper or more effective method though.

After the port is clean, make sure the valve guide and valve stem are good and not etched or pitted by the rust prior to reassembly.
 
I wil probably get yelled at, plug guide hole and sandblast it. Entire head would need to be thoroughly cleaned afterwards.
 
Thanks guys. Lots of great ideas.

Does vinegar damage machined surfaces like the deck or seats? I'd imagine it depends on how long they're exposed?
 
I fire up my propane torch & heat the stuff up then spray with brake cleaner & scrub it with a brass or stainless brush, rinse it out.
Simple. If you like your eyebrows & hair make sure you don't reverse the order lol, experience speaking
 
Pick-up those wire detail brushes. They are just little hand brushes about the size of a tooth brush and they come in stainless or brass wire. One of those brushes and any light hydrocarbon you have laying around the garage (WD-40, PB Blaster, Mineral spirits, kerosene, even ATF) and in 5 minutes I bet it will look fine.
 
Thanks for the ideas guys. I haven't tackled the ports yet, but the valves have all cleaned up very well chucked in a drill and hit on a wire wheel on the bench grinder.

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I really was making a mountain out of a molehill on this one. I was able to easily clean the ports up with a little elbow grease and some various wire wheels, wire brushes, scotchbrites, and WD40. They turned out nice and the valves lapped in nicely. I'm sure they'll work out just fine.

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