I put air to the faulty cylinder and heard air coming from the exhaust, and I had an assistant rotate the motor, but I never got air leaking from the crankcase. (A good sign, I think.) After that, I pulled the valve cover and found this:
Now what are the odds that the valve got bent during all the excitement with the spring exploding and what not? Also, I am missing one of the spring keepers. I plan to look for it some more, I hope it didn’t fall somewhere where it can do some mischief.
Ooo, that’s ugly, and explains why no valve clack (push rod askew). Can you pull the valve up to seat it and show that it isn’t bent?
I think it’s time to pull the head
I plan to replace the spring and push rod, etc. and rotate the engine over by hand to see if the valve is bent, and also do a leak down test to see if my valves are closing like they are supposed to. If that doesn’t come back with favorable results, I will pull the head and rework it again.
If the valve moves freely and seats properly, etc, I will probably go through and replace all the springs and push rods, etc. If one spring exploded, others may not be far behind. If I got lucky this time, I can’t assume I will stay lucky.
I think the spring came apart at startup, so that may have helped.
Probably lucky that it didn’t happen at 70 MPH on the freeway and swallow a valve. 
You might look down in the hole at that cam lobe also; just in case.
I finally replaced the spring this afternoon, and put air to the cylinder with both valves closed. It is still leaking air from the tailpipe, so we will pull the head tomorrow to replace that valve. We will get to put eyes on the top of the cylinder while we have it apart, so we will know if it’s damaged.
I finally pulled the head, the piston is not damaged, but the valve is definitely bent. I intend to replace the valve and put it all back together. Are these valves the type that need lapped when replaced?
Anything else that I must do while I am in here? Water pump was replaced when the head gasket was done a few months ago. I did see one idler pulley that is suspect, so I will replace that as well.
All valves need to be lapped in. Normally, my recommendation would be to have a complete valve job done but your engine has compression issues across the board.
Those figures from earlier about 130-145 show things are getting pretty iffy in there so maybe getting by with replacing one valve is for the best.
If the piston top has any nicks in it then those nicks should be sanded or filed smooth so there are no sharp edges. Sharp edges can glow red and cause pre-ignition.
The head and block should be checked with a precision straight edge to verify flatness.
If out of whack a cylinder head can be cured by surfacing. A block is a whole different ball game.
I only had one cylinder that had less than 140#, that was the #1 cylinder with 130-135, I can’t remember which.
The top of the piston had a mark where it hit the valve, but no sharp edge. I will try to check the block for straightness, I’ll have to find a straightedge.
This is an old Jeep, with 150k miles. Its not a show truck, and never will be. I could easily spend a lot of money trying to make everything perfect, and I’ll still have an old Jeep. I do want to fix this right, but I can’t spend a ton of money on it right now.
What kind of compression numbers should I be looking for?
An engine in very good condition should have about 180 or more on all cylinders. A high miles engine with wear may be in the neighborhood of 150-160. When figures start getting in the 130-140 range this means there is wear. If a wet compression test was done and those numbers jump up by 25 PSI or what have you this means piston ring problems.
There are a few exceptions. Depending upon the camshaft profile a modified engine may have lower numbers.
With the old VW air-cooled Types 1, 2, 3, and 4 (Beetles and so on) a 120 PSI could be considered very good but those engines are entirely different with very low compression ratios and so on. Air cooled including aircraft engines are a different ball game on the numbers.
The general rule of thumb on compression is to multiply 20 X the compression ratio.
If you check flatness, generally .002 thousandths is the maximum allowable deviation but a longer in line 6 cylinder head could be allowed a bit more without need of surfacing.
While I’m often out of the mainstream I suppose, I always aerosol Copper Coat head gaskets, tighten the head bolts, allow it to sit for a day or night, and retighten them again before replacing the valve cover.
This prevents head bolts from relaxing due to gasket crush. Never had a problem with this methodogy; ever. Hope that helps. 
The other variable I am unsure of is how accurate a $35 compression gauge from O-Reilly’s is. I know the cheap Harbor Freight compression gauge can be used to show that you have compression, but the actual readings can be significantly inaccurate. (I didn’t check compression with a $250 compression gauge, and there must be a reason they cost that much, right?)
I was wondering about the “Sealant” the manual mentioned using. That is helpful. Is it worth the extra money to get the better Felpro head gasket, or is the basic one good enough?
The compression gauge you have from O’Reillys should be pretty accurate. I even have one of them along with half a dozen others; both expensive and cheap. Never seen much of a difference from one to the other. The same goes for my vacuum gauges. I have 3 of them; an AutoZone gauge, Snap-On, and a MAC. Not a lick of difference with any of them.
As to head gasket choice, I don’t think it makes any difference whether it’s Fel-Pro or a store brand. While not widely known, the AutoZone Duralast brand gaskets are actually manufactured by Fel-Pro and I would suspect that other store branded gaskets at other parts houses are also made by FP.
This is true of quite a few other parts also including bearings, seals, suspension and steering components, etc.
Regarding my first paragraph about cheap and expensive I might also point out that some expensive tools are made by the same company that makes the cheap ones. Different stamp, different color, or whatever but essentially the same tool.
@ok4450
I somewhat disagree about the tools
Stanley tools also makes Mac tools
Maybe I’m a complete idiot, but I happen to think the Mac brand tools are better than the Stanley brand tools
I’m not saying that an O’Reilly gauge is of better quality; only that I’ve performed countless compression tests using multiple gauges on the same vehicle and never found much of a variation between the cheaper gauge and the expensive one.
Anytime a problem is suspected I always run a test at least twice (on 2 gauges) and sometimes 3 times.
I bought a Blue Point creeper from our Snap-On guy and several years later when a caster broke off I discovered the same manufacturing stamp as the cheap creeper purchased from K-Mart I think it was. Back when K-Mart sold such things.
The only difference between the BP and the KM was that the BP was about 4 times more expensive, had a different color headrest, and the inked logo was different. The manufacturing stamp was hidden on the surface of the caster where it mated to the creeper and once broken it became apparent they came off the same assembly line.
@ok4450
My son brought home a tool flier from work because he couldn’t believe what he saw.
One of the well known tool manufacturers had a plain deep well impact socket set, both metric and standard sizes for get this. $1000.00!
But! If you bought this socket set this month, you would save $250.00 PLUS get a hat and a shirt with logo of the manufacturer for FREE!
He was shocked, and I was shocked!
I think I paid something like $160.00 years ago for both my ATD metric and standard deep well impact socket sets. And they haven’t failed me yet.
Some people feel that they must have that name on that tool. Otherwise it isn’t going to work or last.
Tester
Then professional mechanics must be idiots
Because most of the ones I’ve known have had at least Craftsman brand impact socket sets, if not Mac, Matco, Cornwell or Snap On
I tend to buy used snap on brand impact socket sets on ebay. Occasionally, I will buy new usa-made craftsman impact socket sets, if they’re on sale during club member sale days. Personally, I would prefer craftsman on sale, versus atd
This is just my observation, and by no means a blanket statement, or a condemnation. But, the guys I’ve know that had mostly/only atd and offbrand tools, were usually the ones that didn’t have much pride in their work, and didn’t take their job very seriously
Haven’t bought craftsman impact sockets in a few years. They’re probably all chinese, by now
They’ve really dumbed down their line of tools, lately. They don’t have the craftsman brand screwdrivers with the soft grip. They don’t have their nice hacksaws anymore, only the cheap ones. No more craftsman tape measures. The hammers are still okay, though, and seem to still be usa made. The adjustable wrenches seem to still be okay
No way I’m coughing up a grand for a set of sockets no matter what name is on them. I’ve got plenty of Snap-On, MAC, and Cornwell tools along with a potpourri of other brands including Craftsman.
Some of my Snap-On and MAC stuff, to be honest, is underwhelming and was a colossal waste of money.