How to remove old gasket residue?

[FiremanBob]

The old gaskets have rotted/vulcanized themselves to the engine. Soaking overnight in parts cleaner doesn't seem to soften or loosen the residue at all. What is the best way to get the mating surfaces clean without marring them?

[jesmed]

I doubt this is the "best" way and will look forward to learning from others what the best way is. But when I rebuilt my engine, I used a sharp disposable utility knife blade (the blade only, not installed in a handle) and VERY carefully scraped away the hardened gasket material. If you use this method you have to be very patient and careful not to cut into the relatively soft aluminum, so I don't recommend it for impatient or brute-force type people!

Jesse

[305]

i use spray gasket remover first , then a gasket scraper

[piecutter]

The best possible way I have ever found is what we use here in the shop. A flat, knife sharpening stone and some penetrating oil will do wonders without gougeing the surface. Unlike a knife, the stone will always remain flat against the surface. The 90 degree edge of the stone will push off material rather than try to dig under it, (thats where the knife ends up cutting into the surface when you bump the edge into a raised casting or stuck dowel pin) and the flat under side of the stone will sand away the thin layer of adhesed material thats left, leaving you with a flat, clean, unmarred surface. I use a broken stone that has a sharp angled corner to get into the tight spots. Any good knife, camping or hunting shop should be able to supply you with a set. They usually come in a kit with 2 stones, one medium and one fine grain, as well as a bottle of honing oil. (Look for "Arkansas Stone") I guarantee it to be the best result you'll find out of any of the common methods.

PS: Try useing one of those scrapers on top of the case between all those cylinder studs! You'll tire of that pretty quick!

[FiremanBob]

Thanks for the advice, guys. I've found that carb cleaner and a brass brush are doing the job without scratching the aluminum, although it takes a fair amount of patience and elbow grease. Where the gasket material is too thick to scrub, I was able to slice it off carefully with a razor blade held flat against the surface.

[joeweir1]

I used paint aircraft stripper on gasket material and it worked also.