Do I need to remove the heads to replace the valve stem seals?

 

no, guess i really ought to ask heads on what, but if it's a SBC no

 

How would I keep the valves from falling in? The engine is a L98 on a GTA.

 

any help would be greatly appreciated.

 

use cmpressed air to hold the valves up in place. use around 100 psi in the cylinder.

 

Put the piston at TDC and stuff the cyl full of about ¼" rope.

 

I did the "rope trick" on my 4.3 S-10 engine last weekend. I pulled all the plugs so I could turn the engine easily by hand. After the first two I gave up on trying to figure where the piston was and just stuffed rope in until it wouldn't take any more, then hand cranked the engine until I felt some resistance. This technique works really well. Just make sure you have a LONG piece of rope. Depending on the diameter of course, you might be surprised how much can fit in there if the piston is down the bore a bit.

I used a $15 Sears valve compressor. The procedure that worked best for me was to remove the spring and leave it in the compressor tool. Take off the old seal. Install new umbrella sleeve (if your using them). Put the compressed spring back over the valve stem. Slide the new "O" seal on, using a tiny screwdriver to manipulate it into the lower of the two grooves on the valve stem. Install the locks (a little grease will help hold them in place) and release the spring tool. Oh yeah. VERY important. Cover any holes in the head with a rag while you are working. Dropping one of those locks into the engine could ruin your day.

 

If you do have a compressor, the hose on your compression gage can be used to screw into the spark plug holes. unscrew the gage from the hose and the shrater valve from the other end.

 

make sure the compression gauge doesn't have a check valve, mine from sears does, my snap on don't.