Heads are off the car, and I've got carbon built up on the exhaust valves that I'd like to remove ... how do I get this crud off! The deposits are VERY hard (steel wool w/ light solvents took carbon on the intake valves and chambers off with ease, but doesn't even make a dent on the exhaust valves). Any way to chemically remove it? If not, what's a good way to mechanically remove it without damaging the valves?

 

a wire wheel in a bench grinder. the course kind. take it right off. the way I do it is to mount your valve in a drill, and spin the drill against the wire wheel as its spinning. it'll take it right off, and polish up the valve. do this w/the intake valves too. then buy a tube of valve lapping compound, spread a small amount on the valve face, install the valve in the head, and the drill on the top side of the valve and spin it against the seat. it'll clean it up and rematch the seat in about 20-30 sec. a valve. make sure to clean them and the heads really carefully after though.

and a good chemical to use is "top engine cleaner" from your gm dealership. thats exactly what its made for.

chris

 

Being in the drill won't damage the valve? I don' know how hard the are just wondering.

 

Yes it will hurt the valve. putting it in there like that will scare the stem and chew up the valve guide when put back in. thats old back yard tech you dont wanna do. do this compress the springs take off keepers remove valve seal now pinch the stem between your index and thumb place other hand on head wiggle up and down if it moves you need new guides. If there is carbon chuncked on the back side of the valve you need a valve job. while your at the shop have the heads surfaced.

 

yeah, or if your rich just take them to a shop and let them do it. ofcourse its backyard tech, he asked how he could do it himself. and if your worried about the valve like that then you can just hold the valve in your hand while the wire wheel removes the carbon. the drill wont "chew" up the valves, however if you dont make the drill somewhat tight, it will slip in the drill and leave a sliver the size of a hair. you'll notice it cause when you go to remove the valve it'll be kinda stuck on that part of the valve. in that case, either use a file on the sliver or a very high emery cloth. the only part the drill touches is the keeper end of the valve. so it wont affect the guides at all if you remove the edge you just made w/the drill on the end of the valve. but out of all 16 valves, this has happened to me maybe 6-7 times per set of heads. so not every one. but if you got the money take them to a pro. I personally enjoy doing as much of the work as I can on my engines. thats why i ported my heads myself too.

 

100 bucks got my heads disassembled, revalved, resurfaced (so they weren't banana shaped after blowing a headgasket), and reassembled w/ Isky springs I provided at a pretty reputable shop. That seems pretty cheap for us not so fortunate.