Engine knock

[2bits]

This is not truck related but engine related and you guys are some guru's so I hope it is ok to ask this question...

Last night I went over to my friend's house who has an all original 70 Nova with a 307, and it ran perfect when he parked it FIVE years ago... I was planning on buying the car. I changed the oil, put in a new battery, primed the engine oil before starting it, but when I started it, it knocks pretty bad from deep down in the middle somewhere and blows gray smoke. I couldn't get it to run good enough to drive it around the block, but I did drive up and down his long driveway. It just kept dying on me, I can deal with the running rough, it still has points which I didn't touch, and the smoking may still go away after running for a bit, but does anyone have any suggestions about the knock? I killed it and started it up a few times and ran it until the thermostat opened. Oil is not milky. I primed the engine by unplugging the coil and cranking it for 10 seconds then waiting 10 seconds then cranking for 10 sec and repeating that 7-8 times. Anything I can try to resolve this?

[steveshow]

Do you have an oil pressure guage on the car? It sounds like low oil pressure. I have seen purpose built primers, but I have a priming tool I made out of an old distributor. I took the shaft out, cut the top out where the cap mounts, then cut the top of the shaft down so that it fits in a 3/8" drill. I have used this to prime new engines and cars that have sat for long periods. I hook a mechanical oil pressure guage to the enginge, spin the oil pump with a drill, turn the engine over, then repeat.

[ofnaman]

It sounds to me like a lifter issue. I have noticed that small block chevy's in particular do not like to sit. If it was a rod knock or a main knock it would probably still run half way ok, but if the lifters are bad the valves are not working correctly causing a bad miss. I have had several used engines in various vehicles and have had that problem many times. I would suggest pulling the valve covers and making sure the valves are all moving.

[steveshow]

Good point on the lifters. They usually do not knock, though. If there is a miss, there is a pretty good chance one is stuck. It sounds ghetto, but I have solved this issue before adding some kerosene to the oil, running the car for a while, then changing the oil. A deep knock sounds like lack of oip pressure or a bad bearing, though.

[2bits]

No oil pressure gauge Just dummy lights. I put 10w 30 in it to start out with. I figure since it is a little thinner it would "sink in" better after a long sit, then I would put 10w 40 in it after that. It's getting oil so I don't think I need to prime it again, but the low pressure makes sense to me. I guess I can install a gauge...

It doesn't sound like a lifter "tap", like I have heard in the past, more like a knock, I don't know if lifters can make that kind of sound. (I can swap engines in my sleep, I just never tore deep into one before).

When I first start it, it will run smooth (sometimes knock sometimes not) and about 1 min later, it will be knocking and missing pretty bad, but it will idle by itself. I've heard and seen people drop some tranny fluid in the carb to blow it out, then change the oil, but that would just clean the valves and cylinders right?

I'll pull the valve covers and see what I get. Any other ideas for me to try are very welcome!