Okay John, here's the whole story from a shade tree mechanic on his 78 trip around our star: since I was going to be under the hood for a long time, I started by letting all of the air out of the front tires to give me a little more working room. You'd be surprised how much that helps and it levels up the engine a bit. I then proceeded to get everything out of the way that kept me from having clear access to the valve covers. I then removed all of the spark plugs and ran a compression test for the record. All cylinders came in at 180-190 psi. After removing the valve covers and the radiator cooling fan, I removed the distributor cap and inserted my marker template beneath the rotor (see picture). I set #1 cylinder on TDC and taped the template to the distributor to keep it in place.
Since I was going to use air at TDC to keep the valves in place and I didn't want the piston to move, I used a 5/8 deep well, 1/2" drive socket with a short cheater, to grab the harmonic balancer bolt. In order to hold the ratchet, cheater and socket in place, I cut a piece of wood and wedged it between the ratchet head and a piece of plywood placed against the radiator. I'm sure there are many other ways to hold the wrench in place but this worked well for me. I used the ratchet to rotate the engine to the next TDC position for the valve seal work. My plan was to do all of this work in the firing order sequence. That way, I could adjust each set of valves as I went.
As for the spring compressor tool, I tried two different screw type tools but they were way too clumsy and hard to use for me. You can rent these tools for free at many auto supply stores. I went on line and the tool which I thought looked best was the Proform Valve Spring Compressor 66848. None of the auto stores carried it but offered to order one (8-10 day delivery). Amazon had it for $24.00 so I bought one. It's a stud mounted lever type tool (see picture) and it worked
GREAT!
As for the work procedure, I thoroughly cleaned all of the rocker stud nuts with a solvent and marked the top of each one with white paint. Then, I removed both rockers and push rods, making note of exactly how they came out. I then slowly injected 50psi of pressure and watched the rotor for any movement. Then I used a 3/4 deep well, 1/2" drive socket to hit the top of each spring, pretty hard a couple of times, with a heavy hammer in order to loosen the valve stem keepers. Next, I put three washers over the stud, applied the tool with another washer and used an old 3/8"-24 nut from my miscellaneous nuts and bolts, to tighten everything read good. Then I used the lever to apply enough pressure to expose the keepers enough to catch them with a magnet. After removing the tool, sometimes the spring would stay stuck to the head so I would whack it again with the 3/4" socket and it would turn loose. I had to pry the intake seal off but could just grab and lift off the exhaust seal as it is a much lessor seal. I used a 7/16 deep well, 3/8" drive socket turned upside down, to tap the seal in place. With the seals in place, I put the springs back on using grease to hold the keepers in place. Before putting the rockers back on, I gave the springs another couple pretty hard wacks to be sure everything was securely in place and didn't fly apart. I then adjusted the valve tension according to the manual and in most cases, the white mark on the nut ended up about a quarter turn past its original position.
I went to #8 cylinder next and repeated everything. When I was on #5, the exhaust spring was stuck and when I tapped it, I could hear a lot of air and realized that the valve had dropped. Since I was at TDC, the valve only had a short fall so I grabbed it, and when I pulled it up, it immediately stuck shut. I would have been you know what, if I hadn't been at TDC.
One last thing, I wanted to save #7 for last because the brake booster and cruise control servo make the working space very limited with this tool. I decided to skip ahead and after finishing #2, I modified the tool by cutting the lever off and went back to #7. It worked like I hoped it would and I was able to compress the spring enough to get the keepers off and back on by just tightening the nut much more.
I took my time and all in all, everything went pretty much according to plan. If I was able to complete this job, I believe that almost anyone could. By the way, you may want to watch the thread that I started on Dec.8 titled
Worn/Cracked Valve Guide Seal, to get more comments from a few more guys.
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