The Stovebolt Site Forums The Shop Area Engine Shop 350 needs new valve seals

I have a 350 that lets a little bit of oil down through the top end. Nothing too serious, but it puffs blue smoke when you shift gears. I have heard of being able to swap valve seals with the heads still on the engine, but how is this done? Any suggestions will be appreciated.

Yes it can be done. You need to work each cylinder while it is at TDC (top dead center) or the best method is if you have an air compressor and a hose from a compression gauge you can put air pressure into the cylinder through the plug hole to keep the valves from falling into the engine. You will need a valve spring compressor I have an old one like the $13.25 cheapie in the link but I would recommend getting a better one for your first experience with valve seals. I believe this procedure will have lots of information on the internet and in repair manuals for your engine. Try Google "replacing valve seals on a small block chevrolet". Good luck,
Vern

Thanks Vern, I'm going to have to try that out once I quit getting snowed on every time I go outside to work on it.

You may want to check the valve stem for wobble once you take the first spring off. The valve guides are noted for being the cause of your trouble. Back in the 70's when we did valve jobs on stuff we would usually knurl the valve guides and sometimes get marginal results. Just make sure you look deeper than just replacing the valve seals (o-rings) to make sure your going to have a good result with the work your doing. Don

I would recommend the cup type valve seals like Perfect Circle offered.

Thanks Don and Dave, I will make sure to look into that stuff.