Re: Low compression

Posted by Richter12x2 On 2014/4/29 10:27:31

While you've got it apart, I'd clean everything as well as you can with gasoline or carb cleaner and a toothbrush - there's a lot of carbon buildup there that can interfere with sealing.

It's hard to tell from pictures, but looking at the headgasket, it looks like the first and last cylinder going out has more buildup than the rest, which might point to a leak. It could just be the picture though - the rest of them look pretty good.

Looking at the head, (not well versed in Packard yet so I can't tell if it's the first or last cylinder) but see how the one cylinder is quite a bit nastier than the others? That points to some sort of leak or issue as well. The spots that I see there, are those metal, or something else?

Were it me, I'd clean everything as well as I could, with gasoline or B12 chemtool, get the valves and piston tops as clean as possible, see if you can get the headgasket clean again as well. Ideally you'd use a new one (not sure who the best choice for that is, I hear Kanter and Max Merritt a lot, but I'm new to Packards) but there's a real chance that you'll end up needing to replace it a second time.

So new headgasket or sparkling older gasket, clean up the surfaces where it goes on with a razorblade carefully - you don't want any nicks or gouges (which should be pretty difficult to do with cast iron head and block, but still, be careful.) After getting off the worst of the carbon, I like to give it a quick wipe with 220 grit or so sandpaper on a block or paint stir (to keep it as flat as possible). Bolt it back together and see what you have.

If you're real determined, you can turn the engine over and look around the pistons - you should see the piston rings contacting the cylinder walls all the way around.

If it's any comfort though, I don't see anything yet that I'd be very concerned about.