Hello everyone, new here, and thanks for any and all help!
I have an 85 Silverado I just built a 350 for. I'm a pretty good mechanic, but this is something I've never seen. engine runs great, I just changed the oil for the first time the other day. had thicker break in oil in it. when I changed it to regular oil I started hearing a noise intermittently that sounds like the oil is being aerated. I pulled the oil cap, and it goes away. there is a lot of internal vacuum, I can set the oil cap back on top of the hole, and it will suck it down! never seen that! this is a 79 model 350 block, .30 over, standard pistons, stock Edelbrock cam, and a set of double hump heads, 194/202 valves. Intake is a Edelbrock Victor jr, air gap. (it has no vac ports) I guess my question is, anyone seen this? and should I change intake? thanks folks


Charlie

 

Acts like you don't have a atmoshere air supply, in other words the opposite of a pcv, needs air as well as vacuum in the crankcase

 

im thinking of trying a vented oil cap, i know it will help, but not sure if it will be enough thanks for the reply