Howdy boyos. So I spent the last hour contorting my arms into unnatural angles to get to the 6 and 8 cylinder on this AC 350. The results don't seem great, and I am hoping someone here can confirm.

It's a "YE" code 350 (9.2:1 compression ratio). These were the measurements (at 1600 feet above sea level):

1: 120
3: 120
5: 100
7: 100

2: 120
4: 120
6: 100
8: 100

In other words, the two cylinders closest to the firewall on both sides were all consistently low. I did the oil thing after the low readings and there was no change.

From high school auto-shop, I believe I'm looking at either a head gasket issue (the adjacent cylinders reading low), or a stuck exhaust valve on all the low cylinders. Is this about right?

And more importantly, does this sound like an engine that is worth salvaging? I realize there's very little data here, but that's all I really have. The seller insisted the car was a daily driver, but I didn't take the chance. I towed it home and have only rolled it around my driveway. It does start, idle, and the exhaust is clear.

I guess I'm just trying to decide how steep of a hill I have in front of me here. Thanks!

well, all i can add is that any engine i ever work on, if any cylinder varies by more than 10 pdi up or down, i usually go for tearing it down, checking cylinders, rings, valves, usually turns out pretty accurate that it had weak cylinder or cylinders, so i did what i felt is needed, but 4 at 120 and 4 at 100, still makes me wonder

and thats psi, as for head gasket, never had one cause a variance like your having

My 400 had only been driven a couple hundred miles in the previous 2 years before I bought it. Both 7 and 8 read low on leak down, the other six were right where they were supposed to be. Mechanic said to go out and run it 500-1000 miles, as long as i didn't see any overheating or oil loss and test it again. Two weeks and 600 miles later, all 8 were in the zone. He said he had seen it before with motors that sat around... me, I just felt lucky.

Before you draw any conclusions Tom, use this link and a vacuum gage to get a better idea of what's going on.

http://www.secondchancegarage.com/public/186.cfm

Wow, that proves the vacuum gauge is probably one of you best tools at finding and identifying an engine issue.

Yup, you can repair just about anything on these cars with a vacuum gauge, multimeter, test light & timing light.

Thanks for the link and suggestion, Jeff. I have a vacuum gauge and I will definitely break it out -- maybe even today if I can tear myself away from work.

And speaking of work, I am realizing that -- if I had the option -- I would gladly spend time in the garage instead of the office.

Maybe I have OCD.