Here's a procedure for changing valve springs on a TB with the heads on. It could probably use some more pics, so if anyone gets ambitious and would like to add to the procedure PM me and I can forward you the Word document.
Use a compression tester with a female air chuck end attached and fill the cylinders with compressed air.. Way more simple and I'm not stuffing garbage into my cylinder.
Keeping the valves up is the easy part.. Compressing the springs is hard.. At least I found so. I had to modify my tool a great deal to make it work..
they make a tool for 3.8 series 2 blocks (w-body grand prix monte carlo lesabre etc) that work on those
Cotton's sells a homemade spring compressor made from a modifed rocker arm for those of us who aren't able to fabricate our own. It was easier for me to just order it from them. Turn the engine over so that the last rocker arm on the passenger side is down - that was the only was I was able to get the passenger side valve cover out. Used compressed air to keep the springs up. Took me about 2 1/2 hours. Don't drop the keepers. I dropped one twice and it gave me a good scare. A pocket screwdriver with a magnet on the end worked well for me and plenty of patience.
Keep in mind not everyone has access to compressed air. This document clearly indicates it is for the "rope" method. If a clean nylon rope is used there is nothing to worry about. This isn't in the procedure, but after I was done changing springs and had the plugs still out I unplugged the ECM and cranked the motor over several revolutions, just to be on the safe side.
I prefer to use compressed air but if I used the rope method it would definitely be a good idea to spin the motor over a few times before putting the plug back in just in case any debris got in the cylinders. It's great to have budget tricks like the rope trick but don't we all need an air compressor??? I paid $250 at sears 8 years ago and still going.
