I've had an '82 F150 for about 8-1/2 years. It has about 180,000 miles on it, and the engine, while it ran flawlessly (as far as being dependable and smooth running) had little compression left, and burned a tremendous amount of oil. The compession was bad enough so it wouln't hold itself parked on an incline. I saw my chance to buy another 300 for $100 an have it installed for another $150 (I'm on excellent terms with the junkyard guy....). Well, he put it in, and just sitting there running, seemed to run fine, no noises, no leaks, etc. I noticed, though, that it had a little miss on acceleration, and I also had to downshift more often when turning onto a side road, or even going through town I could no longer run it smoothly unless it was "down a gear" more than before. I replaced the cap and wires, played with the timing, etc, all of which slightly improved it, but it wasn't "right". I did a compression test. Now bear in mind, I don't really believe the numbers I got, as it's an old gauge with questionable accuracy, but it was only for comparative purposes. All the cyls had 165-170 lbs except for #2 which had 60. I repeated the test to be sure. I then squirted some oil into #2, repeated the test, and got the same results. At that point I figured I must have a burnt valve. The junkyard guy wanted to "make it right", but I didn't expect him to come good for a $100 engine, so we agreed that he'd work on it, and just use me right on the labor. He pulled the head, and called me, saying he didn't see anything wrong with the valves in #2, but he did see a little bit of scorching on the head gasket. He thought it was possible I could be losing compression through it, but he wasn't sure. So he replaced the head gasket, reassembled it, and it STILL had 60 lbs. He then did the "wet" test, and got 100 lbs. Apparently I didn't put enough oil in when I did it, therefore I didn't see any improvement. He's figuring it's got bad compression rings in that cyl. Many people I've spoken to question that, asking WHY or HOW I could have bad rings on only one cyl. Some have wondered if the rings are just stuck. So yesterday, after driving it and getting it up to operating temperature, I pulled the #2 plug and poured about a cup of Marvel's Mystery Oil into the cyl, hoping it might get in there and unstick it, IF that is the case.

Meanwhile, my junkyard guy is looking for another 300, and if he doesn't find one soon, I'll just have him put rings in this one and get it over with.

My question is, has anyone had a scenario like this? Is it possible to have rings stuck on ONE cyl, and is there a fix short of a teardown? I'm hoping the MM oil will do the trick if that's the case.

Scott

 

Scott, If a lower ring gets stuck there is a tendency for the ring above it to align the ring gap to the ring gap of the stuck ring. Another possibility is more than one ring is stuck on this cylinder.

The best way to free a stuck ring is with Auto-RX. Change your oil filter and add 10 ozs of ARX then drive 1000 miles. It will increas the compression on all your cylinders, and reduce the difference in compression between your cylinders. The only problem is the cost of the product will be half as much as you paid for that engine, because you'll probably have to treat it twice. It is on sale through the end of the year though. I'll get the link for you.

Auto-Rx Christmas Sale 2003

MM is a solvent which will work on a temporary basis, but you need esters disolve the carbon between the rings groves so it can be carried away by hot oil.

A cheaper solution is to pour a little Neutra right into the cylinder and let it sit for three days. Then put some in the oil and run it for 500 miles and drain it.

 

That compression is too low even if you free the rings. It is possible for one cylinder to be more wore out than the rest.

What needs to be done is to mic. the bore on the cylinder that is low. It most likely has more taper than the rest.


It could however run and Marvel mystery oil in wherever you can get it should help.
That stuff works for everything anyone ever used it for. It truely is a Marvel and a Mystery.



tom