250 compression

So I finally got a chance to check the compression on the used motor I picked up. I always pick the hottest days to work on the van.

Anyway, it reads 150, 120, 150, 150, 150, 90. Not real stoked about the 90, does that indicate a serious issue or maybe just a valve adjustment?

Yeah, I was told about the leakdown testers - will it work with a tank of compressed air? I think I read it's only supposed to need 15psi, any more it can move the pistons...???

I did fill each cylinder via the plug holes with Mystery Oil and let it sit three weeks, and manually cranked it a couple of times each week. Before hooking up the starter today I hand cranked with the plugs out, and no oil squirted out. So I think it successfully seeped through as it was supposed to. Was told it would get rid of any carbon deposits that might cause a false high pressure reading.

I've been told to pour some Mystery Oil through the oil fill hole too, free up the workings there, but didn't do that yet. I read it's basically a kerosene base fluid. ???

Hopefully AZ loans out the leakdown testers too....

OK, so bang on what part? I tapped a bit on the top of some of the springs (hammer on a short block of wood) and not much seemed to happen.

It's that first cylinder, up by the water pump. I took the rocker arm off completely, but just sort of pinged on the top of the valve. Didn't know how hard to tap it and didn't want to bust anything.

A dowel goes into the cylinder 5 inches past the plug threads, so it seems as though the piston is down a bit. But I don't see any movement on the valve, giving it a pretty solid hit. But I am not hammering it like you would a big nail. I can see gunk on all the valves, like a Techron commercial. Should I pour a little oil or something on top of each one through the manifold openings and let it sit a bit?

crowbar? How about I tap the top of the valve with my sledge? haha Anyway, haven't been able to do much, kid wrangling duties today.

But I'll check the compression on the engine in the van, then pull the battery to retest the "new" one.

that is one nice looking fuel line...

After the crowbar check the valves and pushrods move freely, #5 went from 120 to 150, but #1 still stuck at 90 and I gave it several tries. So now I am at 150, 150, 150, 150, 150, 90

>:-(

What I can see of the valves and seats, it's pretty gunky in there. Could it be I just need to flush it out somehow for a better seating? Or probably just needs a valve job...

>>:-(

And that should be when the timing mark on the pulley matches the tab on the timing gear cover, right?

The valves are surely out of adjustment after I messed around with the rocker arms to do the crowbar test.