Snoopy11 5,718 #26 Posted October 11, 2021 (edited) This here is what you don't want to see... Don Edited October 11, 2021 by Snoopy11 Share this post Link to post Share on other sites
Snoopy11 5,718 #27 Posted October 11, 2021 (edited) For the valve seats... You can take a sheet of Emory cloth, cut out several 2" x 2" squares and poke a hole in the center. Sticking the Emory cloth squares onto the valve, you can reach into the valve chamber and turned the valve stems with your fingers, while keeping light pressure on the valve head. Rotate the squares back and forth on the seat, switching from medium grit to fine grit as needed. Don Edited October 11, 2021 by Snoopy11 1 Share this post Link to post Share on other sites
Snoopy11 5,718 #28 Posted October 11, 2021 New valves would be about 40 bucks... probably worth your investment... but again, you 'might' be able to get away with reusing your old valves, as long as there is an airtight, liquid tight seal. Don Share this post Link to post Share on other sites
oliver2-44 10,679 #29 Posted October 11, 2021 25 minutes ago, 1979 C-101 said: I did Snoopy11's test and after two hours the exhaust leaked very little but the intake leaked down completely within a minute. Snoopy11, what do you mean in your last message "valve stems"? I can tell you that through the outlet of the block the exhaust valve stem is not shiny or rusty, kind of grey in color. The intake valve stem is shiny in some places and has rust in other places. If you don't have a 1 gallon can of carb dip, you can clean the head up with a plastic scraper or even a piece of hardwood sharpened to an angle scraper. You just don't want to use any hard metal scraper that would scratch/gouge the aluminum head. From what you've told us I don't see any reason you need a total rebuild. But at a minimum you need to get that intake valve to seal . your hope is some carbon on the stem or seat or rust is preventing that intake valve from seating. I would also check if the intake valve stem is bent or head is warped. i like to chuck them in my drill press on the slowest speed and hold a pencil tip as a fixed point to compare to. Since you will be pulling the breather, I would pull both valves, clean ALL of the valve surfaces , stem bottom of head, seating surface, top with a brass or fine steel wire brush in a grinder. Then I would inspect them with a magnifier glass. If you only see tiny pits you can probable lap them and check if it reseals. If you have large pits or burn marks time to grind valves. Check the seat in the block for pits or burn marks as well. Share this post Link to post Share on other sites
Snoopy11 5,718 #30 Posted October 11, 2021 1 minute ago, oliver2-44 said: If you don't have a 1 gallon can of carb dip, you can clean the head up with a plastic scraper or even a piece of hardwood sharpened to an angle scraper. You just don't want to use any hard metal scraper that would scratch/gouge the aluminum head. From what you've told us I don't see any reason you need a total rebuild. But at a minimum you need to get that intake valve to seal . your hope is some carbon on the stem or seat or rust is preventing that intake valve from seating. I would also check if the intake valve stem is bent or head is warped. i like to chuck them in my drill press on the slowest speed and hold a pencil tip as a fixed point to compare to. Since you will be pulling the breather, I would pull both valves, clean ALL of the valve surfaces , stem bottom of head, seating surface, top with a brass or fine steel wire brush in a grinder. Then I would inspect them with a magnifier glass. If you only see tiny pits you can probable lap them and check if it reseals. If you have large pits or burn marks time to grind valves. Check the seat in the block for pits or burn marks as well. MONEY!!! Don Share this post Link to post Share on other sites
1979 C-101 1 #31 Posted October 11, 2021 I'll do as the two of you suggest with the valves. It will be a winter project. Thanks again to everyone!!! Share this post Link to post Share on other sites
