Re: Low compression

Posted by Richter12x2 On 2014/4/30 12:00:15

It's not a problem at all! These old engines are fairly low compression and very forgiving compared to some of the newer ones, and should run fine with a little attention. So while it would be wonderful to spend a couple of grand and get that nice 47 angle valve job, line bore, head planed, crank reground etc, you should be able to get it running decent with what attentions you can administer at home.

You're doing it exactly right so far - ask all the questions you need to, and don't worry about what anyone thinks. Understand what you're doing and get comfortable with it before starting and you'll come out fine.

Engines run fine with stuck rings all the time - if I'm remembering right, BigKev mentioned in his project blog that he was running for quite a while with stuck rings, and eventually the heat cycles and oil broke down the carbon enough to free them. If they're not scratching the cylinder walls, then you can just run them for a while and see if they free up.

Alternatively, since you're already in the engine, you can pick up a piston ring set pretty inexpensively, and change them out while you're in there. You'll have to remove the pistons to do that, which means you'll have to get the oil pan off the bottom, unscrew the bolts on the connecting rods where they go around the crank, and pull the pistons out one at a time - installing rings isn't hard work, and the tools for it are pretty cheap. If you google or youtube search on replacing piston rings, you should find a ton of how to videos and step by steps, and pistons are pistons for the most part, so the same concepts should apply from a chevy or ford engine over to a Packard engine.

Rather than sending out for a valve job, you can lap the valves yourself with a kit from OReilly or AutoZone - it comes with a stick with suction cups at each end and two tubes of paste, rough and fine. Basically you compress the spring (valve spring compressors can be bought or loaned from OReilly or Autozone) Compress the spring enough to pull the keepers off (using a 99cent magnet keeps you from dropping them into the engine). With the spring off, pull the valve down, put the rough paste on the back of the valve (where it touches the other metal) then twist it back and forth a few times to clean it, then wipe the rough compound off, do it again with the fine, you should be able to get good improvement just from that, and the $30 in kit is a lot nicer than hundreds of dollars for a 3 angle valve job. Again, valve lapping should be pretty well documented online, too.

Really, the only remotely tricky part about doing engines is making sure all the moving parts (valves, pistons, etc) go back on in the same order they came off (each valve and each piston back into the same holes they came out of originally), and making sure the camshaft and crankshaft are lined up correctly.

Just take your time, go slow, and if you're holding a sledgehammer or angle grinder or a welder, take a minute to ask yourself why and maybe head back to the computer for some more questions.

Expensive machinery and sterile cleanroom environments are nice, but remember people have kept these things running for years with hand tools, in the open air, under trees dropping acorns and pollen and everything. Take care to keep things as clean as you can, and don't get frustrated, and you should be fine.