Valve stem seals removal with head still on block
Any tips or tricks on removing the valve stem seals with the head still on the block? I’ve done several head gasket jobs in the past, but I’ve never attempted to replace the seals with the head still on.
I know I can use compress air to keep the valve from dropping. I’ve also heard of feeding a nylon rope into the cylinder and bring the piston to TDC on compression stroke. Even with the heads off, it can be a challenge seperating the retainer and keepers and that’s my fear, trying to seperate the retainer and keepers.
If it matters, I have a 91 S10/Sonoma with a 4.3. For the past several months I have been getting a puff of blue smoke during cold start. By the time I put the truck in gear and drive out the driveway the blue smoke will disappear. As the months go by, the puff of blue smoke is getting bigger. But it still disappear by the time I drive down the block.
there are compressors (really an improper name. it is more like a bar with holes in the right places) that can be used as a lever to compress the spring and retainer. While compressed, the keepers are removed and the spring released.
you have the right idea with the air or rope. If using air, have the piston at TDC as well because if you remove the retainer and lose air pressure, the valve will fall and depending on how long he valve stem and how long the stroke, you may lose it in the cylinder. Most likely not since most valves have enough build-up on the stems to prevent it from falling through but why chance it.
I prefer the rope because if using air, if the retainer is stuck tight, you can still push the valve down sometimes as the air prssure does not provide enough resistance to break the retainer free.
