Is it possible to do it without pulling the heads? thanks; Webster

 

Yes, the best method to use is one using a bunch of rope to hold up the valves while you work on it. It is listed in many repair manuals. If you have compressed air available you can use the air to place torque on the engine. Some people use air alone to hold up the valves but if you place too much pressure on a valve you can lose the valve. I find the combined method is better than either method alone.

 

Obviously Eric (Torque1st) is a belt and suspenders kinda guy

The compressed air trick works great if you have it and and if the valves are in pretty decent shape. If they're leaky then it gets a little more dicey. Replacing valve springs with just air is a piece of cake. Since the seals tend to require a little more finger/valve contact it's not a bad idea to use the rope method even if just to avoid the potential of dropping a valve into the cylinder.

 

I had a little "experience with dropping a valve using just the air method alone. It was not pleasant. The rope method worked better and no adapter for compressed air was needed. A wrench served to turn the crank and hold it. But if you have a piece of rope AND compressed air it is so much easier...