Hello all,

Well the engine in the '68 XL pretty much went Tango Uniform. I had it running quite well for the last couple weeks, by quite well, I mean if you babied it, it was fine and really behaved itself. Well 2 days ago I was out doing errands in it and a couple times I noticed when I let off the throttle coming to a stop the car would start bucking. But if you gave it throttle it revved up fine and accelerated fine (rolling eyes). So what gives. I came home and just parked it in the usual garage spot hoping it was just a "thing" and would be ok in the morning because I don't want to deal with this right now, or really ever as this thing is getting on my nerves.

However yesterday morning it didn't get the memo and it was cold and wouldn't stay running and it was bucking like it was missing on more than one cylinder. Super-duper... I had to sit on the throttle till it warmed up and was chugging on its own. So I start the process of cylinder balance test by taking off one plug wire at a time on the cap. Well 4 and 7 are completely dead, I mean they do nothing. Just swell, one on one bank and one on the other. That's not good.

So I pull the plugs, they look like brand new. That's not good either. I grab the compression tester, unplug the ignition and test both cylinders, both are struggling to make 100 PSI cranking. Well on the whole, that's not good, but that's still enough to light off. I put the plugs back in and start it and magically it's running fine. That's not good either as a whole.

With that I did my errands yesterday, well that lasted about 10 minutes and back to chugging and stalling in gear at idle. Sure enough 4 and 7 aren't doing anything at idle. Thinking well maybe it has two bad plugs that are shorting the HV. So I grab two new platinum ones and still 4 and 7 completely dead and you can hear the spark jumping to the wire off the cap just holding it there, so they are sparking. I revved it up to about 3500 RPMS and then something bad happened. It just started making all kinds of mechanical internal noise and was shaking the car pretty vigorously. I let off the throttle and it just dies, start it with gas and it just dies. Great….

I get the timing light out and in cranking the base timing magically jumped to over 30 BTC. That distributor was tight so it didn't move. Now I'm really scratching my head. I move it back down to 12 BTC and it starts and idles but still nothing on 4 and 7, if I rev it up there's really loud noised out of the rocker covers.

That's it, stick a fork in it, it's done. I can't explain the sudden shift in base timing. But I can hypothesize that the camshaft ate at least 2 lobes and maybe some of the metal ended up in the oil pump and the load sheared the pin on the dizzy gear and moved the timing. I bet if I cut open the oil filter I will find at least 5 kinds of unhappiness in there.

I remember the seller saying he changed the oil before we bought it, I wonder if he didn't add ZDDP and with a high mileage camshaft, the lack of those lubricants just finished it off. Now the race is on to make the Z-code 390 out of the pile 68 LTD work once more. I ordered all the stuff for it, sans the valves.

Has anyone noticed the shortage of engine parts???

I had to order from 5 different places to get all the parts. It's pretty bad when you have to scavenge off of E-Bay and Amazon for parts. For just a stock rebuild I had to order from Summit, Rock Auto, Fleece Bay, Amazon, and Cylinder Head Supply. That's nuts….. just nuts…

By stupid chance I timed the dissection of the 68 LTD parts car pretty well. I was thinking about using its C6 as well, but I noticed it's not the original transmission to the car.

It has a small leak, and by small leak I mean like Han Solo having a slight weapons malfunction in the rescue scene at the Death Star.

The pan didn't look to horrible on the inside.

There's a C6 in there somewhere I'm sure of it.

Found it.

The serial doesn't match the serial of the car, but can anyone confirm the 8 Z means it's a 68 and mated to a Z code engine? I am not sure of the codes stamped.

Since I have no idea what this came out of, I have no idea of what the valve body calibration is, so I'll just keep this as a spare for now and will do the other spare C6.

Here's the new engine candidate. The serial on this engine does match the serial on the VIN so it's the original Z-code 390.

For an 50+ year old abandoned car, it doesn't look too bad. Well so far.

I knew it bent a pushrod and a lifter vomited its guts out a year ago and it was running on 7 cylinders.

The cylinders do not look too bad. There's a little lip on the edge. Still have to check taper.

This side is ok too.

Oh wow the original timing chain and there's not much wiggle in the chain. I am surprised. I'm starting to think the odometer is correct at 71K miles and has not rolled.

Some of the lifters are pitted and that's normal for a car sitting outside unsheltered for god knows how many decades without being run.

The camshaft seems original as well, although there are no numbers on it. Just FoMoCo.

Here's a good reason to stay atop of coolant changes, the rear cylinders are nearly filled with goo.

The engine ran most of its life in the leaded fuel era as the bottom of the oil pan still has about 1/8" of a gray lead slurry and there's lead slurry on most of the other parts.

The plan is to just give this engine a back yard refresh to last 40-50K miles reliably in the XL, until I can get a proper 390 built. With the lack of parts (part manufacturers moving out of commifornia to other states) it will take quite some time for the parts chain to re-emerge. That added to I can't seem to find a trusted machine shop locally, I'll try and do it all at home as long as it doesn't need a cylinder bore.

The heads however need new valve guides and I will try that at home. One thing I did learn, the hard way is never run an engine that's been sitting without disassembling, cleaning, lubing and putting it back together. This engine had old hardened oil in the valve guide and when I ran this, it had virtually no lubricity and it ate the valve stems and valve guides.

Sure it's fun to get something old and neglected running but it's an expensive experience, especially if you want to use that engine later on. I know there's all kinds of automotive resurrection videos and they can be fun to watch, but keep in mind the damage that is being done.

The only reason why I bought this '68 LTD was for its frame, at the time I didn't care about the drive-train and just got it running for 3 years. Well now that I need the engine, I just shot myself in the foot and have to replace the valves and guides as a result. Let it be a lesson.