Hi,

Ive got the heads off my motor right now for installation of AFR heads.

Whats the best way to prep the heads? I was planning on using a scotch-brite and a little bit of water to 'clean-up' any high points.

I was going to stuff rags in the cylinders, though I still think crap will get in there. I plan to shop-vac anything out that fell in there.

Also, how should I do anything to the piston tops? Someone I work with suggested brake cleaner and a soft towel. Then use shop-vac to suck out anything that fell in there.

They also suggested coating the cylinder walls with 10w-30 oil as well.

I have 2 main concerns:
1. Scotch-brite pads alone may not take off all the encrusted previous head gasket from the motor deck
2. ALl the junk (metallic head gasket bits) that fall into the cylinder / or water jacket.

Any advice is appreciated.

 

I would not use scotchbrite unless you are washing the block with soap and water afterwards. Aluminum oxide contamination from the scotchbrite is a real concern. That stuff will break down into particles that can pass through an oil filter.

Scotchbrite--------NEVER !! - Bob Is The Oil Guy

I used lacquer thinner and a rag to begin. What it could not remove, I gently used thinner, a razor blade, and vacuum. Seems like I may have used oil too(to reduce the chance of scratching the surface...its been awhile). I would hold a rag with thinner on the spot(soften up deposits), use a little oil, lube the surface, then carefully use the blade and a vacuum. I used an angle of 20-30* for the blade. The flatter you can lay it, the less the chance of a gouge(less chance to bit into the surface).

If using a razor blade, then you must be very careful not to gouge the surface of the block. Its more critical when you get to aluminum(heads), because a razor blade's corners can scratch the soft surface. The trick to it is not to press down with extreme force and don't come off the surface with a corner of the blade and then try to come back on it with the point. You must lift up the blade and reposition it to fully be on the surface. Don't pressure the corners of the blade. It will gouge.

I was over an engine stand/workbench for all this and had a large range of control. If the engine is still in the car then it could be very tough to keep control of the blade. If uncertain of your ability with the blade, then may be best not to use it....or at the very least practice on a piece of flat steel and aluminum to get the feel of it.

I'm sure others will chime in, but I would avoid the scotchbrite at all costs.

 

No scotchbrite, no cloth shop towels to wipe anything down (like the small red ones). Abrasives get everywhere, and the lint from those cloth towels can as well. A friend of mine rebuilt his first engine in his old 77 Pontiac. He used red shop rags to clean EVERYTHING after it got back from the machine shop. He didn't like the oil presure after breaking it in for 500 miles and pulled the pan and cut open the filter. The oil filter and pickup was loaded with enough lint to knit another rag ahaha.

Simple scraping with a gasket scraper, clean with gasket cleaner or something like toulene or kerosene to get heavy grease off. Make sure not to gouge any surface, and this method is really only good if you are not using an MLS or steel shim gasket. With MLS, you need a specific finish on the surfaces in order to seal.

 

I use a brand new, sharp razor blade and the spray gasket remover. Then some brake cleaner to make sure there is no grease or oil residue.

Make sure you wear gloves, that gasket remover burns like acid when it gets your exposed skin.

 

The scotch brite pads I have don't appear to be a metal? Or perhaps I'm mistaken...

Scotch brite is a generic term. Is the scotch brite green pad/ yellow sponge the aluminum oxide type?

There is also hard plastic scotch brite sponges (hard plastic on both sides).

Bob the oil guys descriptkon of scotch brite makes it sound like its steel wool or something.

The good news is the heads are already cleaned up. Its the engine deck I'm worried about.

 

Scotch brite pads eventually wear - where do you think those fibers end up?

They are great for cleaning parts with the capacity to further clean/wash them in a tank, but not for an assembled engine. The razor blade method described above is your best bet.