Knocking! Plz help

[Haulin302]

I took the 4 barrel carb off my 1970 302 to make sure the gasket wasnt leaking. When i started it up it idled fine then after 10 sec something started rattling and knocking. It has never done that before. It wont do while cranking the starter and all the valves move . I removed the sparkplugs and they are fine. I had just been driving it and it drove fine. Other than a little boggy on the low end(thats the reason for removing the carb). What could be making that noise?

[Haulin302]

I put it back together and started it. It ran for a couple seconds without making a noise then it would rattle every so often then it got to the point it did it constantly. I also dont have oil pressure at idle and i haven't revved it to see if there is pressure on throttle. Before it had really good oil pressure. It ran good too. What could start doing that right after startup.

[cep62]

Did you drop a screw or nut or piece of gasket in the intake while it was apart?

What made you think a gasket was leaking?

BTW
welcome to the site.

[DuckRyder]

Did you drop the oil pump drive shaft when you pulled the distributor?

[cep62]

Did you drop the oil pump drive shaft when you pulled the distributor?

Good thought.

[Haulin302]

Did you drop a screw or nut or piece of gasket in the intake while it was apart?

What made you think a gasket was leaking?

BTW
welcome to the site.

Well i ripped the gasket a little bit when i took the carb off a while back and thought i could get away with it. So i thought maybe it was leaking and running really lean when only 2 barrels were activated causing it to bog.

Did you drop the oil pump drive shaft when you pulled the distributor?

I am an idiot. I didnt think i had oil pressure but thats just because my sender unit came unplugged so that was a relief. But now i have taken all the lifters and cleaned them thinking that was the problem. Nothing was collapsed or stuck so I thought it could be leaking down causing the banging. But i have now put it all back together and I still have it along with 2 rocker nuts backing off. Not sure why the studs arent pulling out. Any ideas what is causing this. I think my next step will be to put new lifters in. Cause all my pushrods are straight.

[sargentrs]

Grab a stick, about 1/4"-1/2" dia and cut the ends off smooth. Put your thumb over one end and stick your thumbnail to your ear canal. Shadetree stethoscope. You can hear everything going on in your engine. Run the engine and touch the other end of the stick to various places on your engine. Down the valve covers, between the exhaust manidolds, around the sparkplugs, oil pan, intake, alternator case, power steering pump, anything that rotates. See if you can't narrow down where it's coming from. I had a strange noise on a Toyota one time that turned out to be an exhaust shield cracked at a mounting bolt. Thought the engine was tapping but it was just that shield tapping the manifold at low rpm.

[Twisted_Steel]

Good idea Sarge.. never tried the stick and thumb method. Then again it's easier to buy an automotive stethoscope. They're only about $5.00

[DuckRyder]

A pry bar works too...

[sargentrs]

Then again it's easier to buy an automotive stethoscope. They're only about $5.00

That's true! I always tell myself I'm going to get a real one but never do. You should see the looks I get when I'm checking out a used car and walk over to the nearest tree and cut off a branch

[Twisted_Steel]

Hahaha... Sarge, you're just too dang funny. I bet that does raise an eyebrow or two