Timing

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Trailbeast,

I just heated the engine up and pulled all the plugs as soon a it cooled down a bit. Did a compression test.

Here are the numbers. With notes. Also all were cranked for 8 seconds.

1 150 Reached that number in about 3 seconds
2 155 Ditto
3 150 Ditto
4 160 Ditto
5 150 Ditto
6 140 Took about 5 seconds to reach this mark.
7 130 Took almost the full 8 seconds to get here.
8 165 Took about 3 seconds.

So another leak down, but I suspect that # 7 has a valve problem. I am going to try a different approach and just pump a ton of air into the cylinder and see of I can spot listen for a different sound in intake as well as exhaust from a known good cylinder like # 4. Will also do #6 as it is showing a tad low and it reacted much like #7.

I am going to assume that when a cylinder takes longer to reach max compression that this is likely valve. Would seem odd to be rings I would think.
 
Fluctuating vacuum usually means leaking valves, not vacuum leaks. Combined with the fact that you hear air coming out of the tailpipes I'd say you at least have leaks in the exhaust valves. The % of leakage your getting from the L/D tester indicate you have real troubles. I'd be prepared to tear the whole thing down. 45% is waaay too much. Compression tests pretty much indicate the same thing. Although I trust leakdown tests a lot more since compression test only show peak pressures.
Good luck!
 
Lonewolf,

Yup the engine is coming out. Likely issues with valves and rings. I did a kind of bizarre test. I put a balloon on the hose that connects to the PCV valve and then pumped 80 PSI into each cylinder. Most took like 10 to 12 seconds to inflate the balloon. Now of course some pressure is coming out the right bank open breather, but I was just looking for a comparison. The ballon does not blow up, just goes from a collapsed state to the basic shape of a balloon. But when I did #7 the ballon blew up in a little over a second. I also put the hose in a jar of water and the buble rate was much higher than all the other cylinders. So that tells me I have a busted ring likely. But after talking with a member who lives just north of me and is known on this board as quite the SB expert, I also think that the rest of the issue is likely valves and probably exhaust valves. His guess is that heads did not have hardened seats installed. I know that the guy that originally built this engine has thoughts of racing it. So maybe he was planning on running racing fuel. And then sold the car to the guy I bought it from and did not tell him the issue with the seats.

So now the engine is coming out and luckily the gent will make my engine all better.

I have done as much as I can and I sure have learned a lot.
 
I like your common sense tests and procedures .Well, the good part is that when you're done rebuilding you will know every part for future reference. No more mysteries. Are you pulling the engine yourself? I've got a lift and stand if you want to borrow them.
 
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