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frank, Chevrolet Technician
Category: Chevy
Satisfied Customers: 3420
Experience:  33 years experience,24 years of Chevroler/GM experience and training .ASE Recertified Master Tech,
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I rebuilt a small block 350 cu in..motor running..blows..dipstick

Resolved Question:

I rebuilt a small block 350 cu in. The engine has been bored 30 over everthing is new. When I got the motor running it blows the oil dipstick out starting around 1000 oil will drip out of the tube. The higher the rpm''s get the worse the engine oil comes out. I changed out the pcv''s and put non restricktive caps in the valve covers and still blows oil out the dipstick. If I pull the cap out of the valve cover it stops oil out of the dipstick, but there is a very large amount of pressure coming out of the cover. I have the motor installed in my boat. I have a edelbrock performer rpm intake, edelbrock 600 cfm marine carb, 3/4 race cam. Every thing else is new. please help me with some possiblities of what to do. At this time I am totally lost. Hoping that do not have to pull the motor out?   thanks larry
Submitted: 9 years ago.
Category: Chevy
Expert:  frank replied 9 years ago.
The dipstick tube is suppose to extend down into the oil,about 8 " lower then the block,is it?
Customer: replied 9 years ago.
Reply to frank's Post: I purchased a new dipstick tube and stick for the motor it is located on the passenger side of the motor looking from the front. The tube has a brace that bolts to side the block under the head. So I'm hoping that it is the correct one?
Expert:  frank replied 9 years ago.
The tube is suppose to go into the oil to keep from oil comeing out of the tube-either the tube will pass thru the block of is flush to the block and a lower tube extendes inside the engine and is seperate-which one do you have.
Customer: replied 9 years ago.
The tube is the one which goes inside of the tube hole, just above the oil pan. As to my knowledge it is the correct one. The only way I can get the oil to quit coming out of the dipstick tube is to pull one of the caps on the valve cover and the back pressure is very high volume of pressure. What causes such a high volume of pressure? I have built motors before and have never seen this before. to me it is very mind boggling!!!!!!!
Expert:  frank replied 9 years ago.
Two things that cause oil to come out of the dipstick tube-crank case pressure from blow by and /or no pcv vacuum of the crank is literally throwing oil up the dip stick.It sounds more like a blow by problem with the rings not seated.If you running a big cam-try the l88 pcv valve which is the same for a chevette-it has a pick elbow on it.
Customer: replied 9 years ago.
This may sound like i'm not very smart but how do get vacuum of the crank. If the rings are not seated will they take time to seat. Is there any thing that I can do to help the rings seat. I took the pcv valve's out and put two chrome caps that has foam inside and a tube to put the pcv hoses to the air cleaner. when I take the pcv valve or the chrome cap out of the valve cover the noise it makes sounds like a cork coming out of a wine bottle?
Expert:  frank replied 9 years ago.
For the pcv to work it needs manifild vacuum run to it-usuaaly from the base of the carb and uses a 3/8 in vacuum hose-How is yours set up.The valve is in the valve cover and the engines vaccum pulls the air thru the valve out of the valve cover
Customer: replied 9 years ago.
The 3/8 line runs from the valve cover to the outside of the air cleaner. the only vacuum line on the engine is behind the carb and is hooked to the dist vac advance. the air cleaner is a marine app. and the hoses for the pcv attach to the outside by two hose adapters that are build to it. this is also an after market intake it's a edelbrock- performer rpm, and a edelbrock carb marine app.
Expert:  frank replied 9 years ago.
There should be a big plug on the base of the carb at the rear-you need to get engine vacuum from a central point below the carb to the pcv valve to get it to work right
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