The next step was to fit the spring compressing tool over the rocker stud and keep it in place by tightening the rocker nut in place by three or four turns. Some valves were easier to work on than others because of various things in the way. In general the worst ones were toward the back of the engine because it was harder to reach back there, or the brake master cylinder was in the way, or the carburetor or vacuum hoses or whatever. Here is the spring compression tool in place:

 The technique for removing the valve spring keepers involves compressing the spring enough to allow the top of the valve and the keepers to poke up through the top of the spring and the keepers to pop free. This sounds a little easier than it was. First, several of my keepers were sort of heat welded to the valve stems and the spring caps and would not come loose easily. This can cause the valve to lower with the spring when you use the tool and let the air pressure out of the cylinder, which is not a problem when trying to get the keepers off, but is more serious when putting them back on. I ended up using a little penetrating oil around the tops of the valves and some judicious tapping with a small hammer to get the keepers to separate from the valve stems. Removing the keepers while the spring is compressed requires a bit of finesse, as well as trust that your other arm is strong enough to keep the spring compressed while your fingers are in the danger zone grabbing the keepers! A friend recommended using a magnet to pull the keepers away from the valve stem, which would have worked nicely, I expect, had they not been so sticky. I had to wiggle most of them free with the tips of my fingers. At this point I should also mention that I lost one keeper for about a week in the middle of this project. It feel down into the suspension and as this is a two wheel drive truck there are lots of little nooks and crannies for a small part to hide down in there. I eventually retrieved it later by using one keeper to make sure the valve didn’t fall into the head and using compressed air to blow out the crevices in the suspension. Luckily the missing keeper blew out as well and I found it on the ground under the truck. Here’s a picture of a valve and spring with the keepers removed:

Removing the spring itself also proved to be more difficult than I expected in some cases, requiring a bit more tapping, while carefully shielding the spring with one hand lest it come free and shoot away from the engine. They hold quite a bit of bounce in them and I had to search around the engine compartment for spring parts that had bounced away on at least one occasion. The cap on the top of the spring is actually two parts and they are easy to lose if the spring comes loose unexpectedly.

The next step was to remove the old seal, wipe up the valve stem a bit then place the new pair of seals. I used both an OEM o-ring type seal in place of the old ones and an umbrella type seal as recommended by several sources on the net. This proved valuable in a later stage of the process as well as hopefully providing a better seal around the valve. Here’s the valve stem with the old seal removed:

 The old seals were extremely brittle, in most cases either already broken away from the stem and impossible to find (presumably having circulated in the oil and hopefully having been removed in an oil change) or crumbling as soon as they were touched. Here’s an example of one of the more intact ones after removing it:

 After the new seals were in place the next step is to replace the spring, then compress it again and put the keepers back. A couple of times I had trouble with the valve dropping a bit when I compressed the spring and the air pressure escaping from the cylinder. Luckily, having both types of new seals in place kept the valve from dropping all the way into the head and requiring removal of the head for retrieval. When I lost pressure like that I had to carefully remove the tool and the spring and make sure the valve was completely reseated before trying again.

Getting the keepers back in place was tricky as well. I found the easiest way to do it was to push the spring laterally toward the middle of the engine as I compressed it down with the tool and getting a keeper in place on the upper side (toward the carburetor) of the spring first, then sliding the second keeper in on the opposite side. This process may have been easier with a screw type spring compressor instead of the lever, but they are much more expensive to buy and I knew this project would take me a few days to get done so I didn’t want to have to rent one multiple times.

Once the keepers are back in place the valve assembly can be put back together by replacing the push rod and rocker. I tightened the rocker nut to within three or four turns of where it would finally need to be so I could easily tell which valves had already been done and which remained.

After all the valves were completed the last step before replacing the valve covers and getting the spark plugs and wires in place was to adjust the valve lash. This process consisted of setting each cylinder in turn to the compression stroke, so that both valves were closed, by manually turning the crankshaft by means of the nut on the front of the crankshaft pulley and a large ratchet. Once both valves on the cylinder were closed I slowly tightened the rocker nut till I could feel a little drag against the inside of the push rod socket on the rocker when I spun the push rod. Then I would tighten the nut one quarter turn tighter. I found this method on the web somewhere and it seemed to be pretty good. Evidently there are other methods but I couldn’t find details on any of them. Once the valve lash was adjusted on all the valves I reconnected the battery (spark plugs and wires still disconnected) and had my wife crank the engine over for 30 secs or so and watched the rockers. They all looked pretty good so I figured I was in good shape. I am nothing in the way of a professional mechanic so it’s probably safe to assume I could have done a better job with this step. The tightness of the rockers and how much they can move from side to side as well as up and down is pretty important to how the engine runs. If this weren’t such an old engine and didn’t have a myriad of other potential issues I would worry more about this and likely have someone more experienced check it out.

Lastly I cleaned all the old gasket material from the valve covers, applied some RTV silicone and new gaskets and replaced the covers. I then put new spark plugs in all 8 cylinders and rewired them according to the firing order stamped on the intake manifold.

As I mentioned in another post I was afraid that the engine would take a lot of effort to get started after doing all this because it had been sitting for almost a year without being run before I really started this project. In the end it fired right up after I had cranked it over a few times, then found out I wasn’t getting spark in the cylinders because of a battery lead to the distributor which had come loose as I was working on things (there were several bundles of wires that had to be moved out of the way as I put the valve covers back on so no surprise). That particular wire had come loose during other repair projects before so I knew just where to look after verifying that I wasn’t getting spark.

The truck sounded pretty good initially, heated up well and ran pretty smoothly, but seemed to be burning quite a bit of oil judging by the amount of blue smoke coming from the tali pipe. I figured I could live with that as long as all that extra exhaust pressure didn’t return. The extra exhaust pressure was one of the main indications (other than emissions testing) that gas that was getting into the cylinders wasn’t all getting burnt so if the pressure stays away after replacing the valve stem seals hopefully things will be good. I got a little scare after running the engine for a few minutes because it started to kinda chug and put more pressure out the tail pipe, but after heating up fully it didn’t seem to do that at all. Later last night when I ran it again it seemed good as well. I’ll go try it again tonight and see how things seem after sitting for a day. I really hope this makes things noticeably better because I can’t afford to be without the truck anymore on the one hand, but I also can’t afford to take it to get fixed by a professional on the other hand!